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Bosco L, Yañez O, Schauer A, Maurer C, Cushman SA, Arlettaz R, Jacot A, Seuberlich T, Neumann P, Schläppi D. Landscape structure affects temporal dynamics in the bumble bee virome: Landscape heterogeneity supports colony resilience. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 946:174280. [PMID: 38942311 DOI: 10.1016/j.scitotenv.2024.174280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 06/23/2024] [Accepted: 06/23/2024] [Indexed: 06/30/2024]
Abstract
Virus spillovers from managed honey bees, Apis mellifera, are thought to contribute to the decline of wild pollinators, including bumble bees. However, data on the impact of such viruses on wild pollinators remain scarce, and the influence of landscape structure on virus dynamics is poorly understood. In this study, we deployed bumble bee colonies in an agricultural landscape and studied changes in the bumble bee virome during field placement under varying habitat composition and configuration using a multiscale analytical framework. We estimated prevalence of viruses and viral loads (i.e. number of viral genomic equivalent copies) in bumble bees before and after placing them in the field using next generation sequencing and quantitative PCR. The results show that viral loads and number of different viruses present increased during placement in the field and that the virus composition of the colonies shifted from an initial dominance of honey bee associated viruses to a higher number (in both viral loads and number of viruses present) of bumble bee associated viruses. Especially DWV-B, typical for honey bees, drastically decreased after the time in the field. Viral loads prior to placing colonies in the field showed no effect on colony development, suggesting low impacts of these viruses in field settings. Notably, we further demonstrate that increased habitat diversity results in a lower number of different viruses present in Bombus colonies, while colonies in areas with well-connected farmland patches decreased in their total viral load after field placement. Our results emphasize the importance of landscape heterogeneity and connectivity for wild pollinator health and that these influences predominate at fine spatial scales.
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Affiliation(s)
- Laura Bosco
- LUOMUS - Finnish Museum of Natural History, PL 17 - P.O. Box 17, 00014, University of Helsinki, Finland; Division of Conservation Biology, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland.
| | - Orlando Yañez
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Schwarzenburgstrasse 161, 3003 Bern, Switzerland.
| | - Alexandria Schauer
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Schwarzenburgstrasse 161, 3003 Bern, Switzerland.
| | - Corina Maurer
- Division of Conservation Biology, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland; Agroecology and Environment, Agroscope, Reckenholzstrasse 191, 8046 Zürich, Switzerland; Ecosystems Landscape Evolution, Institute of Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zürich, 8092 Zürich, Switzerland.
| | - Samuel A Cushman
- Wildlife Conservation Research Unit, Department of Biology, University of Oxford, Oxford, United Kingdom
| | - Raphaël Arlettaz
- Division of Conservation Biology, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland.
| | - Alain Jacot
- Division of Conservation Biology, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland; Swiss Ornithological Institute, Regional Office Valais, 1950 Sion, Switzerland.
| | - Torsten Seuberlich
- Division of Neurological Sciences, University of Bern, Bern, Switzerland.
| | - Peter Neumann
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Schwarzenburgstrasse 161, 3003 Bern, Switzerland.
| | - Daniel Schläppi
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Schwarzenburgstrasse 161, 3003 Bern, Switzerland; School of Biological Sciences, University of Bristol, Life Science Building, 24 Tyndall Avenue, BS8 1TQ Bristol, United Kingdom.
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2
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Krüger J, Buchholz S, Schmitt S, Blankenhaus K, Pernat N, Ott D, Hollens‐Kuhr H. You are what you eat - The influence of polyphagic and monophagic diet on the flight performance of bees. Ecol Evol 2024; 14:e70256. [PMID: 39224153 PMCID: PMC11368496 DOI: 10.1002/ece3.70256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 08/12/2024] [Accepted: 08/17/2024] [Indexed: 09/04/2024] Open
Abstract
Movement performance of insects is an important measure of physiological fitness and is likely affected by novel stressors associated with global change. Reduced fitness can lead to smaller foraging areas and thus to decreasing abundance, diversity and nutritional quality, which could weaken insect populations and contribute to global insect decline. Here, we combined two different methods: An experimental semi-field design applying treatments in outdoor flight cages and a follow-up experiment conducted in the laboratory, in which different parameters of movement performance, such as (a) velocity, (b) duration and (c) distance of an insect's flight can be quantified. We kept colonies of the bumblebee Bombus terrestris under contrasting nutritional conditions and measured treatment effects on the movement performance of individuals. Monophagously fed bumblebees showed reduced movement performance than polyphagously fed bumblebees. In particular, they stopped more frequently during flight, flew shorter distances and showed less often flight duration of 20 min. Our results suggest that nutritional deficiency due to a monophagic diet leads to reduced flight performance, which can have dramatic negative consequences for bees. Reduced flight performance may result in decreased availability of host plants, which may negatively affect stress resistance of bees and brood provisioning, facilitating extinction of insects. Although food of great nutritional value is an important compensator for the negative effects of different novel stressor, such as pesticides, it is not much known how to compensate for the effects of nutritional stress, especially in landscapes dominated by monocultures. However, our experimental approach with semi-field and laboratory components has high potential for further studies investigating the impact of different stressors on the physiological fitness of insects but also body mass, or reproductive success and to find factors that may mitigate or even overcome the negative effect of stressors on insects.
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Affiliation(s)
| | - Sascha Buchholz
- Institute of Landscape Ecology, University of MünsterMünsterGermany
- Centre for Integrative Biodiversity Research and Applied EcologyUniversity of MünsterMünsterGermany
| | - Sophie Schmitt
- Institute of Landscape Ecology, University of MünsterMünsterGermany
| | | | - Nadja Pernat
- Institute of Landscape Ecology, University of MünsterMünsterGermany
- Centre for Integrative Biodiversity Research and Applied EcologyUniversity of MünsterMünsterGermany
| | - David Ott
- Centre for Biodiversity Monitoring and Conservation ScienceLeibniz Institute for the Analysis of Biodiversity ChangeBonnGermany
| | - Hilke Hollens‐Kuhr
- Institute of Landscape Ecology, University of MünsterMünsterGermany
- Centre for Integrative Biodiversity Research and Applied EcologyUniversity of MünsterMünsterGermany
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3
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Zhao X, Jiang J, Pang Z, Ma W, Jiang Y, Fu Y, Liu Y. Tracking Existing Factors Directly Affecting the Reproduction of Bumblebees: Current Knowledge. INSECTS 2024; 15:654. [PMID: 39336622 PMCID: PMC11432074 DOI: 10.3390/insects15090654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2024] [Revised: 08/24/2024] [Accepted: 08/28/2024] [Indexed: 09/30/2024]
Abstract
Bumblebees are primary social insects and a vital class of pollinating insects. Their distinctive reproductive mode is characterized by the independent initiation and construction of the nest by the queen and the subsequent production of sufficient workers, males, and gynes following colony development. After successful mating, the queen transitions to the first phase of its annual life cycle. The reproductive processes are directly influenced by environmental factors, including floral resources and pesticides. Moreover, the reproductive level is regulated by biological factors, particularly the role of workers, who participate in egg laying and pass on their genetic material to the next generation of queens. Successful reproduction can only be achieved by maintaining colony development under natural or artificial breeding conditions. Consequently, understanding the known factors that influence bumblebee reproduction is essential for developing conservation strategies for wild bumblebees and for successfully breeding diverse bumblebee species. Breeding various bumblebee species is crucial for in-depth research into known factors and for further exploration of other potential factors, which will also help to meet the demand for pollination in agricultural facilities globally.
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Affiliation(s)
- Xiaomeng Zhao
- College of Animal Sciences, Shanxi Agricultural University, Taigu, Jinzhong 030801, China; (X.Z.); (J.J.); (Z.P.); (Y.J.)
| | - Jingxin Jiang
- College of Animal Sciences, Shanxi Agricultural University, Taigu, Jinzhong 030801, China; (X.Z.); (J.J.); (Z.P.); (Y.J.)
| | - Zilin Pang
- College of Animal Sciences, Shanxi Agricultural University, Taigu, Jinzhong 030801, China; (X.Z.); (J.J.); (Z.P.); (Y.J.)
| | - Weihua Ma
- College of Horticulture, Shanxi Agricultural University, Taiyuan 030031, China;
| | - Yusuo Jiang
- College of Animal Sciences, Shanxi Agricultural University, Taigu, Jinzhong 030801, China; (X.Z.); (J.J.); (Z.P.); (Y.J.)
| | - Yanfang Fu
- HeBei Provincial Animal Husbandry Station, Shijiazhuang 050035, China;
| | - Yanjie Liu
- College of Animal Sciences, Shanxi Agricultural University, Taigu, Jinzhong 030801, China; (X.Z.); (J.J.); (Z.P.); (Y.J.)
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4
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Straub L, Sittisorn T, Butdee J, Promsart W, Rueangwong A, Camenzind D, Maitip J. Age-dependent hypopharyngeal gland size and protein content of stingless bee workers, Tetragonula pagdeni. PLoS One 2024; 19:e0308950. [PMID: 39150928 PMCID: PMC11329107 DOI: 10.1371/journal.pone.0308950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Accepted: 08/01/2024] [Indexed: 08/18/2024] Open
Abstract
Eusocial insects, such as stingless bees (Meliponini), depend on division of labour, overlapping generations, and collaborative brood care to ensure the functionality and success of their colony. Female workers transition through a range of age-specific tasks during their lifespan (i.e., age-polyethism) and play a central role in the success of a colony. These age-specific tasks (e.g., brood care or foraging) often closely coincide with key physiological changes necessary to ensure optimal performance. However, our understanding of how nutrition, age, and polyethism may affect the development of such physiological traits in stingless bees remains limited. Here we show that pollen consumption and age-polyethism govern hypopharyngeal gland (HPG) acini size and protein content in Tetragonula pagdeni. By conducting a controlled laboratory experiment we monitored the effect of pollen consumption on worker bee survival as well as assessed how a pollen diet and age affected their HPG acini width and protein content. Further, we sampled nurses and foragers from field colonies to measure the effect of age-polyethism on HPG acini width. We found that pollen consumption enhanced survival and led to increased HPG acini width and protein content and that HPG acini were as expected largest in nurse bees. Our findings highlight the beneficial effects of an adequate diet for physiological development and health in stingless bees and reveal that age-polyethism is the key factor governing HPG size in worker bees. As HPGs are imperative for collaborative brood care-an essential component of eusociality-the data provide a foundation for future studies to investigate the impact of potential environmental stressors on a critical physiological trait in stingless bees which may serve as a proxy to understand the effects at the colony level.
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Affiliation(s)
- Lars Straub
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Faculty of Science, Energy and Environment, King Mongkut's University of Technology North Bangkok, Rayong, Thailand
- Centre for Ecology, Evolution, and Behaviour, Department of Biological Sciences, Royal Holloway University of London, Egham, United Kingdom
| | - Tanatip Sittisorn
- Faculty of Science, Energy and Environment, King Mongkut's University of Technology North Bangkok, Rayong, Thailand
| | - Jinatchaya Butdee
- Faculty of Science, Energy and Environment, King Mongkut's University of Technology North Bangkok, Rayong, Thailand
| | - Woranika Promsart
- Faculty of Science, Energy and Environment, King Mongkut's University of Technology North Bangkok, Rayong, Thailand
| | - Athitta Rueangwong
- Faculty of Science, Energy and Environment, King Mongkut's University of Technology North Bangkok, Rayong, Thailand
| | - Domenic Camenzind
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Jakkrawut Maitip
- Faculty of Science, Energy and Environment, King Mongkut's University of Technology North Bangkok, Rayong, Thailand
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5
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Bernauer OM, Jain A, de Bivort B, Holbrook NM, Myers SS, Ziska LH, Crall JD. Elevated atmospheric CO 2 has small, species-specific effects on pollen chemistry and plant growth across flowering plant species. Sci Rep 2024; 14:13760. [PMID: 38877021 PMCID: PMC11178917 DOI: 10.1038/s41598-024-63967-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 06/04/2024] [Indexed: 06/16/2024] Open
Abstract
Elevated atmospheric carbon dioxide (eCO2) can affect plant growth and physiology, which can, in turn, impact herbivorous insects, including by altering pollen or plant tissue nutrition. Previous research suggests that eCO2 can reduce pollen nutrition in some species, but it is unknown whether this effect is consistent across flowering plant species. We experimentally quantified the effects of eCO2 across multiple flowering plant species on plant growth in 9 species and pollen chemistry (%N an estimate for protein content and nutrition in 12 species; secondary chemistry in 5 species) in greenhouses. For pollen nutrition, only buckwheat significantly responded to eCO2, with %N increasing in eCO2; CO2 treatment did not affect pollen amino acid composition but altered secondary metabolites in buckwheat and sunflower. Plant growth under eCO2 exhibited two trends across species: plant height was taller in 44% of species and flower number was affected for 63% of species (3 species with fewer and 2 species with more flowers). The remaining growth metrics (leaf number, above-ground biomass, flower size, and flowering initiation) showed divergent, species-specific responses, if any. Our results indicate that future eCO2 is unlikely to uniformly change pollen chemistry or plant growth across flowering species but may have the potential to alter ecological interactions, or have particularly important effects on specialized pollinators.
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Affiliation(s)
- Olivia M Bernauer
- Department of Entomology, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI, 53706, USA.
| | - Anupreksha Jain
- Department of Entomology, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI, 53706, USA
- Department of Organismic and Evolutionary Biology, Harvard University, 52 Oxford Street, Cambridge, MA, 02138, USA
| | - Benjamin de Bivort
- Department of Organismic and Evolutionary Biology, Harvard University, 52 Oxford Street, Cambridge, MA, 02138, USA
| | - N Michele Holbrook
- Department of Organismic and Evolutionary Biology, Harvard University, 52 Oxford Street, Cambridge, MA, 02138, USA
| | - Samuel S Myers
- Bloomberg School of Public Health, Johns Hopkins University, 615 N Wolfe St, Baltimore, MD, 21205, USA
| | - Lewis H Ziska
- Mailman School of Public Health, Columbia University, 722 W. 168Th Street, New York, NY, 10032, USA
| | - James D Crall
- Department of Entomology, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI, 53706, USA
- Department of Organismic and Evolutionary Biology, Harvard University, 52 Oxford Street, Cambridge, MA, 02138, USA
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6
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Han L, Chang ZM, Ren CS, Chen XS, Smagghe G, Yuan YG, Long JK. Colony performance of three native bumblebee species from South China and association with their gut microbiome. INSECT SCIENCE 2024. [PMID: 38516802 DOI: 10.1111/1744-7917.13351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 01/09/2024] [Accepted: 02/02/2024] [Indexed: 03/23/2024]
Abstract
Bumblebees play an important ecological economic role as pollinators in nature and agriculture. For reasons of biosecurity, many countries promote the cultivation of native bumblebee species for crop pollination instead of importing "alien" species. In South China, a few bumblebee species are considered useful in this way, particularly, Bombus atripes, Bombus bicoloratus and Bombus breviceps. However, whether they are suitable for artificial rearing and forming healthy colonies for pollination, remains unknown. In this project, queens from the 3 native species of Guizhou Province were collected and colonies were started under standardized conditions. The colonies were scored based on 19 parameters, including the stage of colony development, number and weight of offspring, and diet consumed. The data revealed that B. breviceps had the best performance, produced more workers and consumed the smallest diet. Next, we performed 16S rDNA sequencing of the bacterial communities found in the guts of offspring workers, and then a correlation analysis between colony performance and gut bacteria was conducted. Here, B. breviceps showed the highest diversity in gut bacterial composition, dominated by the bacteria Gilliamella, Snodgrassella, Enterobacter, and Lactobacillus Firm5. The higher the abundance of Snodgrassella, the better the performance of the colony in the foundation stage, and later Lactobacillus Firm5, Apibacter and Bifidobacterium were beneficial during the stages of rapid growth and colony decline. Although we do not understand all of the interactions yet, these correlations explain why B. breviceps demonstrated better colony performance. Our data provide valuable information for breeding local Bombus species and will contribute to developing strong colonies for crop pollination.
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Affiliation(s)
- Lei Han
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education/College of Animal Science, Guizhou University, Guiyang, China
| | - Zhi-Min Chang
- Institute of Entomology/Provincial Special Key Laboratory for Developing and Utilization of Insect Resources, Guizhou University, Guiyang, China
| | - Chang-Shi Ren
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education/College of Animal Science, Guizhou University, Guiyang, China
| | - Xiang-Sheng Chen
- Institute of Entomology/Provincial Special Key Laboratory for Developing and Utilization of Insect Resources, Guizhou University, Guiyang, China
| | - Guy Smagghe
- Institute of Entomology/Provincial Special Key Laboratory for Developing and Utilization of Insect Resources, Guizhou University, Guiyang, China
| | - Yi-Ge Yuan
- Institute of Entomology/Provincial Special Key Laboratory for Developing and Utilization of Insect Resources, Guizhou University, Guiyang, China
| | - Jian-Kun Long
- Institute of Entomology/Provincial Special Key Laboratory for Developing and Utilization of Insect Resources, Guizhou University, Guiyang, China
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Graham KK, Milbrath MO, Killewald M, Soehnlen A, Zhang Y, Isaacs R. Identity and diversity of pollens collected by two managed bee species while in blueberry fields for pollination. ENVIRONMENTAL ENTOMOLOGY 2023; 52:907-917. [PMID: 37498984 DOI: 10.1093/ee/nvad072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/26/2023] [Accepted: 07/10/2023] [Indexed: 07/29/2023]
Abstract
The nutritional needs and foraging behavior of managed bees often lead to pollen collection from flowers other than the focal crop during crop pollination. To understand the pollen needs and preferences of managed bees during blueberry pollination, we identified pollen collected by Apis mellifera Linnaeus, 1758 (Hymenoptera: Apidae) and Bombus impatiens Cresson, 1863 (Hymenoptera: Apidae) colonies across two years. Bumble bees collected a wider diversity of pollens compared to honey bees, whereas honey bees were more focused on abundant resources. Despite blueberries being the most abundant resource in the landscape, it was not the most collected pollen by either bee species in 2018. However, it was the most collected pollen by bumble bees in 2019 and they collected substantially more blueberry pollen than honey bees in both years. In 2018, buckthorn, Rhamnus L. (Rosales: Rhamnaceae) or Frangula Mill. (Rosales: Rhamnaceae), and willow, Salix L. (Malpighiales: Salicaceae), pollens were abundantly collected by both bee species. In 2019, cherry, Prunus L. (Rosales: Rosaceae), and willow (Salix) pollens were collected at high proportions by both species. Brambles, Rubus L. (Rosales: Rosaceae), and white clover, Trifolium repens L. (Fabales: Fabaceae), were also common pollen sources for honey bees, whereas oak, Quercus L. (Fagales: Fagaceae), was collected by bumble bees. Landscape analyses also revealed that certain land cover types were positively correlated with the collection of preferred pollen types. Herbaceous wetlands were associated with collection of buckthorn (Rhamnus/Frangula), willow (Salix), and cherry (Prunus) pollen, which were primary pollen resources for both bee species. There was no correlation between landscape diversity and pollen diversity, suggesting that colonies forage based on nutritional requirements rather than resource availability.
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Affiliation(s)
- Kelsey K Graham
- Department of Entomology, Michigan State University, 202 CIPS, 578 Wilson Road, East Lansing, MI 48824, USA
- Present Affiliation: U.S. Department of Agriculture - Agricultural Research Service, Pollinating Insect - Biology, Management, Systematics Research Unit, 1410 N. 800 E., Logan, UT 84341, USA
| | - Meghan O Milbrath
- Department of Entomology, Michigan State University, 202 CIPS, 578 Wilson Road, East Lansing, MI 48824, USA
| | - Michael Killewald
- Department of Entomology, Michigan State University, 202 CIPS, 578 Wilson Road, East Lansing, MI 48824, USA
- Department of Entomology, University of Manitoba, 12 Dafoe Road, Winnipeg, MB R3T 2N2, Canada
| | - Annuet Soehnlen
- Department of Entomology, Michigan State University, 202 CIPS, 578 Wilson Road, East Lansing, MI 48824, USA
| | - Yajun Zhang
- Department of Entomology, Michigan State University, 202 CIPS, 578 Wilson Road, East Lansing, MI 48824, USA
| | - Rufus Isaacs
- Department of Entomology, Michigan State University, 202 CIPS, 578 Wilson Road, East Lansing, MI 48824, USA
- Program in Ecology, Evolutionary Biology, and Behavior, Michigan State University, East Lansing, MI 48824, USA
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8
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Straub F, Birkenbach M, Leonhardt SD, Ruedenauer FA, Kuppler J, Wilfert L, Ayasse M. Land-use-associated stressors interact to reduce bumblebee health at the individual and colony level. Proc Biol Sci 2023; 290:20231322. [PMID: 37817596 PMCID: PMC10565366 DOI: 10.1098/rspb.2023.1322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 09/08/2023] [Indexed: 10/12/2023] Open
Abstract
In agricultural landscapes, bees face a variety of stressors, including insecticides and poor-quality food. Although both stressors individually have been shown to affect bumblebee health negatively, few studies have focused on stressor interactions, a scenario expected in intensively used agricultural landscapes. Using the bumblebee Bombus terrestris, a key pollinator in agricultural landscapes, we conducted a fully factorial laboratory experiment starting at nest initiation. We assessed the effects of food quality and insecticides, alone and in interaction, on health traits at various levels, some of which have been rarely studied. Pollen with a diluted nutrient content (low quality) reduced ovary size and delayed colony development. Wing asymmetry, indicating developmental stress, was increased during insecticide exposure and interactions with poor food, whereas both stressors reduced body size. Both stressors and their interaction changed the workers' chemical profile and reduced worker interactions and the immune response. Our findings suggest that insecticides combined with nutritional stress reduce bumblebee health at the individual and colony levels, thus possibly affecting colony performance, such as development and reproduction, and the stability of plant-pollinator networks. The synergistic effects highlight the need of combining stressors in risk assessments and when studying the complex effects of anthropogenic stressors on health outcomes.
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Affiliation(s)
- Florian Straub
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Markus Birkenbach
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Sara D. Leonhardt
- Plant-Insect-Interactions, Research Department Life Science Systems, Technical University of Munich, Hans-Carl-von-Carlowitz-Platz 2, 85354 Freising, Germany
| | - Fabian A. Ruedenauer
- Plant-Insect-Interactions, Research Department Life Science Systems, Technical University of Munich, Hans-Carl-von-Carlowitz-Platz 2, 85354 Freising, Germany
| | - Jonas Kuppler
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Lena Wilfert
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Manfred Ayasse
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
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9
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Martinez A, Calhoun AC, Sadd BM. Investigating the influence of diet diversity on infection outcomes in a bumble bee ( Bombus impatiens) and microsporidian ( Nosema bombi) host-pathogen system. FRONTIERS IN INSECT SCIENCE 2023; 3:1207058. [PMID: 38469464 PMCID: PMC10926413 DOI: 10.3389/finsc.2023.1207058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 08/01/2023] [Indexed: 03/13/2024]
Abstract
Diet can have an array of both direct and indirect effects on an organism's health and fitness, which can influence the outcomes of host-pathogen interactions. Land use changes, which could impact diet quantity and quality, have imposed foraging stress on important natural and agricultural pollinators. Diet related stress could exacerbate existing negative impacts of pathogen infection. Accounting for most of its nutritional intake in terms of protein and many micronutrients, pollen can influence bee health through changes in immunity, infection, and various aspects of individual and colony fitness. We investigate how adult pollen consumption, pollen type, and pollen diversity influence bumble bee Bombus impatiens survival and infection outcomes for a microsporidian pathogen Nosema (Vairimorpha) bombi. Experimental pathogen exposures of larvae occurred in microcolonies and newly emerged adult workers were given one of three predominantly monofloral, polyfloral, or no pollen diets. Workers were assessed for size, pollen consumption, infection 8-days following adult-eclosion, survival, and the presence of extracellular microsporidian spores at death. Pollen diet treatment, specifically absence of pollen, and infection independently reduced survival, but we saw no effects of pollen, pollen type, or pollen diet diversity on infection outcomes. The latter suggests infection outcomes were likely already set, prior to differential diets. Although infection outcomes were not altered by pollen diet in our study, it highlights both pathogen infection and pollen availability as important for bumble bee health, and these factors may interact at different stages of bumble bee development, at the colony level, or under different dietary regimes.
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Affiliation(s)
| | | | - Ben M. Sadd
- School of Biological Sciences, Illinois State University, Normal, IL, United States
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10
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Johansson J, Arce AN, Gill RJ. How competition between overlapping generations can influence optimal egg-laying strategies in annual social insects. Oecologia 2023; 202:535-547. [PMID: 37428254 PMCID: PMC10386978 DOI: 10.1007/s00442-023-05411-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 06/15/2023] [Indexed: 07/11/2023]
Abstract
Annual social insects are an integral functional group of organisms, particularly in temperate environments. An emblematic part of their annual cycle is the social phase, during which the colony-founding queen rears workers that later assist her in rearing sexual progeny (gynes and drones). In many annual social insects, such as species of bees, wasps, and other groups, developing larvae are provisioned gradually as they develop (progressive provisioning) leading to multiple larval generations being reared simultaneously. We present a model for how the queen in such cases should optimize her egg-laying rate throughout the social phase depending on number-size trade-offs, colony age-structure, and energy balance. Complementing previous theory on optimal allocation between workers vs. sexuals in annual social insects and on temporal egg-laying patterns in solitary insects, we elucidate how resource competition among overlapping larval generations can influence optimal egg-laying strategies. With model parameters informed by knowledge of a common bumblebee species, the optimal egg-laying schedule consists of two temporally separated early broods followed by a more continuous rearing phase, matching empirical observations. However, eggs should initially be laid continuously at a gradually increasing rate when resources are scarce or mortality risks high and in cases where larvae are fully supplied with resources at the egg-laying stage (mass-provisioning). These factors, alongside sexual:worker body size ratios, further determine the overall trend in egg-laying rates over the colony cycle. Our analysis provides an inroad to study and mechanistically understand variation in colony development strategies within and across species of annual social insects.
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Affiliation(s)
- Jacob Johansson
- Department of Biology, Lund University, Sölvegatan 37, 22362, Lund, Sweden.
- Department of Life Sciences, Georgina Mace Centre for the Living Planet, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire, SL5 7PY, UK.
| | - Andres N Arce
- Department of Life Sciences, Georgina Mace Centre for the Living Planet, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire, SL5 7PY, UK
- School of Engineering, Arts, Science and Technology, University of Suffolk, 19 Neptune Quay, Ipswich, IP4 1QJ, UK
| | - Richard J Gill
- Department of Life Sciences, Georgina Mace Centre for the Living Planet, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire, SL5 7PY, UK
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11
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Russo L, Ruedenauer F, Gronert A, Van de Vreken I, Vanderplanck M, Michez D, Klein A, Leonhardt S, Stout JC. Fertilizer and herbicide alter nectar and pollen quality with consequences for pollinator floral choices. PeerJ 2023; 11:e15452. [PMID: 37334137 PMCID: PMC10269573 DOI: 10.7717/peerj.15452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 05/03/2023] [Indexed: 06/20/2023] Open
Abstract
Background Pollinating insects provide economically and ecologically valuable services, but are threatened by a variety of anthropogenic changes. The availability and quality of floral resources may be affected by anthropogenic land use. For example, flower-visiting insects in agroecosystems rely on weeds on field edges for foraging resources, but these weeds are often exposed to agrochemicals that may compromise the quality of their floral resources. Methods We conducted complementary field and greenhouse experiments to evaluate the: (1) effect of low concentrations of agrochemical exposure on nectar and pollen quality and (2) relationship between floral resource quality and insect visitation. We applied the same agrochemcial treatments (low concentrations of fertilizer, low concentrations of herbicide, a combination of both, and a control of just water) to seven plant species in the field and greenhouse. We collected data on floral visitation by insects in the field experiment for two field seasons and collected pollen and nectar from focal plants in the greenhouse to avoid interfering with insect visitation in the field. Results We found pollen amino acid concentrations were lower in plants exposed to low concentrations of herbicide, and pollen fatty acid concentrations were lower in plants exposed to low concentrations of fertilizer, while nectar amino acids were higher in plants exposed to low concentrations of either fertilizer or herbicide. Exposure to low fertilizer concentrations also increased the quantity of pollen and nectar produced per flower. The responses of plants exposed to the experimental treatments in the greenhouse helped explain insect visitation in the field study. The insect visitation rate correlated with nectar amino acids, pollen amino acids, and pollen fatty acids. An interaction between pollen protein and floral display suggested pollen amino acid concentrations drove insect preference among plant species when floral display sizes were large. We show that floral resource quality is sensitive to agrochemical exposure and that flower-visiting insects are sensitive to variation in floral resource quality.
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Affiliation(s)
- Laura Russo
- University of Tennessee, Knoxville, United States of America
- Trinity College Dublin, Dublin, Ireland
| | | | - Angela Gronert
- Chair of Nature Conservation and Landscape Ecology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | | | | | | | - Alexandra Klein
- Chair of Nature Conservation and Landscape Ecology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
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12
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Nebauer CA, Schleifer MC, Ruedenauer FA, Leonhardt SD, Spaethe J. Perception, regulation, and fitness effects of pollen phytosterols in the bumble bee, Bombus terrestris. AMERICAN JOURNAL OF BOTANY 2023:e16165. [PMID: 37071779 DOI: 10.1002/ajb2.16165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 06/19/2023]
Abstract
PREMISE Many flowering plants depend on insects for pollination and thus attract pollinators by offering rewards, mostly nectar and pollen. Bee pollinators rely on pollen as their main nutrient source. Pollen provides all essential micro- and macronutrients including substances that cannot be synthesized by bees themselves, such as sterols, which bees need for processes such as hormone production. Variations in sterol concentrations may consequently affect bee health and reproductive fitness. We therefore hypothesized that (1) these variations in pollen sterols affect longevity and reproduction in bumble bees and (2) can thus be perceived via the bees' antennae before consumption. METHODS We studied the effect of sterols on longevity and reproduction of Bombus terrestris workers in feeding experiments and investigated sterol perception using chemotactile proboscis extension response (PER) conditioning. RESULTS Workers could perceive several sterols (cholesterol, cholestenone, desmosterol, stigmasterol, β-sitosterol) via their antennae but not differentiate between them. However, when sterols were presented in pollen, and not as a single compound, the bees were unable to differentiate between pollen differing in sterol content. Additionally, different sterol concentrations in pollen neither affected pollen consumption nor brood development or worker longevity. CONCLUSIONS Since we used both natural concentrations and concentrations higher than those found in pollen, our results indicate that bumble bees may not need to pay specific attention to pollen sterol content beyond a specific threshold. Naturally encountered concentrations might fully support their sterol requirements and higher concentrations do not seem to have negative effects.
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Affiliation(s)
- Carmen A Nebauer
- Plant-Insect Interactions, Department of Life Science Systems, Technical University of Munich, Freising, Germany
| | - Marielle C Schleifer
- Department of Behavioral Physiology and Sociobiology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Fabian A Ruedenauer
- Plant-Insect Interactions, Department of Life Science Systems, Technical University of Munich, Freising, Germany
| | - Sara D Leonhardt
- Plant-Insect Interactions, Department of Life Science Systems, Technical University of Munich, Freising, Germany
| | - Johannes Spaethe
- Department of Behavioral Physiology and Sociobiology, Biocenter, University of Würzburg, Würzburg, Germany
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13
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Malfi RL, McFrederick QS, Lozano G, Irwin RE, Adler LS. Sunflower plantings reduce a common gut pathogen and increase queen production in common eastern bumblebee colonies. Proc Biol Sci 2023; 290:20230055. [PMID: 37015273 PMCID: PMC10072944 DOI: 10.1098/rspb.2023.0055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 03/10/2023] [Indexed: 04/06/2023] Open
Abstract
Community diversity can reduce the prevalence and spread of disease, but certain species may play a disproportionate role in diluting or amplifying pathogens. Flowers act as both sources of nutrition and sites of pathogen transmission, but the effects of specific plant species in shaping bee disease dynamics are not well understood. We evaluated whether plantings of sunflower (Helianthus annuus), whose pollen reduces infection by some pathogens when fed to bees in captivity, lowered pathogen levels and increased reproduction in free-foraging bumblebee colonies (Bombus impatiens). Sunflower abundance reduced the prevalence of a common gut pathogen, Crithidia bombi, and reduced infection intensity, with an order of magnitude lower infection intensity at high sunflower sites compared with sites with little to no sunflower. Sunflower abundance was also positively associated with greater queen production in colonies. Sunflower did not affect prevalence of other detected pathogens. This work demonstrates that a single plant species can drive disease dynamics in foraging B. impatiens, and that sunflower plantings can be used as a tool for mitigating a prevalent pathogen while also increasing reproduction of an agriculturally important bee species.
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Affiliation(s)
- Rosemary L. Malfi
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
| | | | - Giselle Lozano
- Department of Entomology, University of California, Riverside, CA 92521, USA
| | - Rebecca E. Irwin
- Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695, USA
| | - Lynn S. Adler
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
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14
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Giacomini JJ, Adler LS, Reading BJ, Irwin RE. Differential bumble bee gene expression associated with pathogen infection and pollen diet. BMC Genomics 2023; 24:157. [PMID: 36991318 DOI: 10.1186/s12864-023-09143-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 01/18/2023] [Indexed: 03/31/2023] Open
Abstract
BACKGROUND Diet and parasitism can have powerful effects on host gene expression. However, how specific dietary components affect host gene expression that could feed back to affect parasitism is relatively unexplored in many wild species. Recently, it was discovered that consumption of sunflower (Helianthus annuus) pollen reduced severity of gut protozoan pathogen Crithidia bombi infection in Bombus impatiens bumble bees. Despite the dramatic and consistent medicinal effect of sunflower pollen, very little is known about the mechanism(s) underlying this effect. However, sunflower pollen extract increases rather than suppresses C. bombi growth in vitro, suggesting that sunflower pollen reduces C. bombi infection indirectly via changes in the host. Here, we analyzed whole transcriptomes of B. impatiens workers to characterize the physiological response to sunflower pollen consumption and C. bombi infection to isolate the mechanisms underlying the medicinal effect. B. impatiens workers were inoculated with either C. bombi cells (infected) or a sham control (un-infected) and fed either sunflower or wildflower pollen ad libitum. Whole abdominal gene expression profiles were then sequenced with Illumina NextSeq 500 technology. RESULTS Among infected bees, sunflower pollen upregulated immune transcripts, including the anti-microbial peptide hymenoptaecin, Toll receptors and serine proteases. In both infected and un-infected bees, sunflower pollen upregulated putative detoxification transcripts and transcripts associated with the repair and maintenance of gut epithelial cells. Among wildflower-fed bees, infected bees downregulated immune transcripts associated with phagocytosis and the phenoloxidase cascade. CONCLUSIONS Taken together, these results indicate dissimilar immune responses between sunflower- and wildflower-fed bumble bees infected with C. bombi, a response to physical damage to gut epithelial cells caused by sunflower pollen, and a strong detoxification response to sunflower pollen consumption. Identifying host responses that drive the medicinal effect of sunflower pollen in infected bumble bees may broaden our understanding of plant-pollinator interactions and provide opportunities for effective management of bee pathogens.
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Affiliation(s)
- Jonathan J Giacomini
- Department of Applied Ecology, North Carolina State University, Raleigh, NC, 27695, USA.
| | - Lynn S Adler
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Benjamin J Reading
- Department of Applied Ecology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Rebecca E Irwin
- Department of Applied Ecology, North Carolina State University, Raleigh, NC, 27695, USA
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15
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Vanderplanck M, Marin L, Michez D, Gekière A. Pollen as Bee Medicine: Is Prevention Better than Cure? BIOLOGY 2023; 12:497. [PMID: 37106698 PMCID: PMC10135463 DOI: 10.3390/biology12040497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/20/2023] [Accepted: 03/23/2023] [Indexed: 03/29/2023]
Abstract
To face environmental stressors such as infection, animals may display behavioural plasticity to improve their physiological status through ingestion of specific food. In bees, the significance of medicating pollen may be limited by their ability to exploit it. Until now, studies have focused on the medicinal effects of pollen and nectar after forced-feeding experiments, overlooking spontaneous intake. Here, we explored the medicinal effects of different pollen on Bombus terrestris workers infected by the gut parasite Crithidia bombi. First, we used a forced-feeding experimental design allowing for the distinction between prophylactic and therapeutic effects of pollen, considering host tolerance and resistance. Then, we assessed whether bumble bees favoured medicating resources when infected to demonstrate potential self-medicative behaviour. We found that infected bumble bees had a lower fitness but higher resistance when forced to consume sunflower or heather pollen, and that infection dynamics was more gradual in therapeutic treatments. When given the choice between resources, infected workers did not target medicating pollen, nor did they consume more medicating pollen than uninfected ones. These results emphasize that the access to medicating resources could impede parasite dynamics, but that the cost-benefit trade-off could be detrimental when fitness is highly reduced.
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Affiliation(s)
| | - Lucie Marin
- Laboratory of Zoology, Research Institute for Biosciences, University of Mons, 7000 Mons, Belgium
| | - Denis Michez
- Laboratory of Zoology, Research Institute for Biosciences, University of Mons, 7000 Mons, Belgium
| | - Antoine Gekière
- Laboratory of Zoology, Research Institute for Biosciences, University of Mons, 7000 Mons, Belgium
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16
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Ren CS, Chang ZM, Han L, Chen XS, Long JK. Higher Essential Amino Acid and Crude Protein Contents in Pollen Accelerate the Oviposition and Colony Foundation of Bombus breviceps (Hymenoptera: Apidae). INSECTS 2023; 14:203. [PMID: 36835772 PMCID: PMC9965574 DOI: 10.3390/insects14020203] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/11/2023] [Accepted: 02/15/2023] [Indexed: 06/18/2023]
Abstract
Pollen is an important source of nutrition for bumblebees to survive, reproduce, and raise their offspring. To explore the nutritional requirements for the egg laying and hatching of queenright Bombus breviceps colonies, camellia pollen, oilseed rape pollen, apricot pollen, and mixtures of two or three types of pollen in equal proportions were used to feed the queens in this study. The results showed that the camellia pollen with a higher essential amino acid content was superior to the pollen with a lower essential amino acid content in the initial egg-laying time (p < 0.05), egg number (p < 0.05), larval ejection (p < 0.01), time of first worker emergence (p < 0.05), and the average weight of workers in the first batch (p < 0.01). It took less time for colonies under the camellia pollen and camellia-oilseed rape-apricot pollen mix treatments, both with a higher crude protein content, to reach ten workers in the colony (p < 0.01). On the contrary, the queens fed apricot pollen never laid an egg, and larvae fed oilseed rape pollen were all ejected-both pollens with a lower essential amino acid content. The results emphasize that the diet should be rationally allocated to meet the nutritional needs of local bumblebees at various stages when guiding them to lay eggs, hatch, and develop a colony.
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Affiliation(s)
- Chang-Shi Ren
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education/College of Animal Science, Guizhou University, Guiyang 550025, China
| | - Zhi-Min Chang
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education/College of Animal Science, Guizhou University, Guiyang 550025, China
- Institute of Entomology/Special Key Laboratory for Developing and Utilizing of Insect Resources, Guizhou University, Guiyang 550025, China
| | - Lei Han
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education/College of Animal Science, Guizhou University, Guiyang 550025, China
| | - Xiang-Sheng Chen
- Institute of Entomology/Special Key Laboratory for Developing and Utilizing of Insect Resources, Guizhou University, Guiyang 550025, China
| | - Jian-Kun Long
- Institute of Entomology/Special Key Laboratory for Developing and Utilizing of Insect Resources, Guizhou University, Guiyang 550025, China
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17
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Leroy C, Brunet JL, Henry M, Alaux C. Using physiology to better support wild bee conservation. CONSERVATION PHYSIOLOGY 2023; 11:coac076. [PMID: 36632323 PMCID: PMC9825782 DOI: 10.1093/conphys/coac076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 11/17/2022] [Accepted: 11/19/2022] [Indexed: 06/17/2023]
Abstract
There is accumulating evidence that wild bees are experiencing a decline in terms of species diversity, abundance or distribution, which leads to major concerns about the sustainability of both pollination services and intrinsic biodiversity. There is therefore an urgent need to better understand the drivers of their decline, as well as design conservation strategies. In this context, the current approach consists of linking observed occurrence and distribution data of species to environmental features. While useful, a highly complementary approach would be the use of new biological metrics that can link individual bee responses to environmental alteration with population-level responses, which could communicate the actual bee sensitivity to environmental changes and act as early warning signals of bee population decline or sustainability. We discuss here through several examples how the measurement of bee physiological traits or performance can play this role not only in better assessing the impact of anthropogenic pressures on bees, but also in guiding conservation practices with the help of the documentation of species' physiological needs. Last but not least, because physiological changes generally occur well in advance of demographic changes, we argue that physiological traits can help in predicting and anticipating future population trends, which would represent a more proactive approach to conservation. In conclusion, we believe that future efforts to combine physiological, ecological and population-level knowledge will provide meaningful contributions to wild bee conservation-based research.
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Affiliation(s)
| | - Jean-Luc Brunet
- INRAE, UR 406 Abeilles et Environnement, 84 914 Avignon, France
| | - Mickael Henry
- INRAE, UR 406 Abeilles et Environnement, 84 914 Avignon, France
| | - Cedric Alaux
- INRAE, UR 406 Abeilles et Environnement, 84 914 Avignon, France
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18
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Perez R, Benbachir M, Decroo C, Mascolo C, Wattiez R, Aron S. Cataglyphis desert ants use distinct behavioral and physiological adaptations to cope with extreme thermal conditions. J Therm Biol 2023; 111:103397. [PMID: 36585078 DOI: 10.1016/j.jtherbio.2022.103397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 10/25/2022] [Accepted: 11/22/2022] [Indexed: 11/29/2022]
Abstract
Some ant species live in hot and arid environments, such as deserts and savannas. Worker polymorphism-variation in worker size and/or morphology within colonies-is adaptive in such ecosystems because it enhances resistance to heat stress and increases the efficiency of resource exploitation. However, species with small, monomorphic workers are also frequently found in these environments. How species with distinct worker size and degrees of polymorphism deal with such stressful environments remains poorly studied. We investigated the behavioral, physiological, and molecular adaptations that may enhance heat and desiccation tolerance in two sympatric species of Cataglyphis desert ants that differ dramatically in worker size and polymorphism: C. viatica is polymorphic, while C. cubica is small and monomorphic. We found that worker size, water content, water loss, and protein regulation play a key role in thermal resistance. (i) Large C. viatica workers better tolerated heat and desiccation stress than did small C. viatica or C. cubica workers. The former had greater water content and lost proportionally less water to evaporation under thermal stress. (ii) Despite their similar size distribution, workers of C. cubica are more heat tolerant than small C. viatica. This higher degree of tolerance likely stemmed from C. cubica workers having greater relative water content. (iii) Under thermal stress, small C. viatica workers metabolized larger quantities of fat and differentially expressed proteins involved in cellular homeostasis. In contrast, C. cubica downregulated the expression of numerous proteins involved in mitochondrial respiration likely reducing ROS accumulation. (iv) Consistent with these results, large C. viatica workers remained active throughout the day; C. cubica workers displayed a bimodal activity pattern, and small C. viatica remained poorly active outside the nest. Our study shows that ecologically similar ant species with different degrees of worker size polymorphism evolved distinct strategies for coping with extreme heat conditions.
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Affiliation(s)
- Rémy Perez
- Department of Evolutionary Biology & Ecology, Université Libre de Bruxelles, B-1050, Brussels, Belgium.
| | - Mohammed Benbachir
- Department of Evolutionary Biology & Ecology, Université Libre de Bruxelles, B-1050, Brussels, Belgium
| | - Corentin Decroo
- Department of Proteomics and Microbiology, Université de Mons, B-7000, Mons, Belgium
| | - Cyril Mascolo
- Department of Proteomics and Microbiology, Université de Mons, B-7000, Mons, Belgium
| | - Ruddy Wattiez
- Department of Proteomics and Microbiology, Université de Mons, B-7000, Mons, Belgium
| | - Serge Aron
- Department of Evolutionary Biology & Ecology, Université Libre de Bruxelles, B-1050, Brussels, Belgium
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19
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Gekière A, Michez D, Vanderplanck M. Bumble Bee Breeding on Artificial Pollen Substitutes. JOURNAL OF ECONOMIC ENTOMOLOGY 2022; 115:1423-1431. [PMID: 36000563 DOI: 10.1093/jee/toac126] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Indexed: 06/15/2023]
Abstract
Bumble bees are important pollinators for many temperate crops. Because of the growing demand for food from entomophilous crops, bumble bee colonies are commercially reared and placed in fields or greenhouses to guarantee sufficient pollination services. Besides, commercial colonies are increasingly used in laboratories for various bioassays under controlled conditions. For both usages, bumble bee colonies are commonly provided with sugar solution and honey bee-collected pollen pellets. However, the latter display several disadvantages since they may contain pollutants, pathogens, or toxic phytochemicals. Consequently, companies have developed pollen-free artificial diets to sustain colonies. Such diets are designed to boost worker health in the field, in complement of floral pollen collected by workers outside the colonies, but their suitability in 'closed' systems without access to floral pollen, such as in laboratory bioassays, is arguable. Here, we used microcolonies of the commercially important bumble bee Bombus terrestris L. (Hymenoptera: Apidae) to assess the suitability of five artificial pollen substitutes and three mixed diets. We also assessed the evaporation rate of the different diets as it could impact their suitability. At the end of the bioassays, microcolonies fed the artificial diets showed a reduced offspring development when compared to microcolonies fed natural pollen, which was partly offset by mixing these diets with natural pollen. By contrast, the artificial diets did not have deleterious effects on worker's health. We discuss the potential nutritional and physical causes of artificial diets unsuitability for offspring development and encourage further research to accordingly establish appropriate pollen-free diets for bumble bee breeding.
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Affiliation(s)
- Antoine Gekière
- Laboratory de Zoology, Research institute for Biosciences, University of Mons, Mons, Belgium
| | - Denis Michez
- Laboratory de Zoology, Research institute for Biosciences, University of Mons, Mons, Belgium
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20
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Quesada-Béjar V, Contreras-Garduño J, Calvillo LKA, García EC. Survival, Body Condition, and Immune System of Apis mellifera liguistica Fed Avocado, Maize, and Polyfloral Pollen Diet. NEOTROPICAL ENTOMOLOGY 2022; 51:583-592. [PMID: 35708899 DOI: 10.1007/s13744-022-00974-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 05/18/2022] [Indexed: 06/15/2023]
Abstract
Nutritional stress is the major factor contributing to decline in the honey bee (Apis mellifera L.) populations given the high degree of dependence on floral resources, and due to the habitat loss. In this sense, monocultures of maize and avocado have great extensions in Mexico, but their impact on the physiology and morphology of A. mellifera is unknown. This research evaluated the effect of total protein content in monofloral (maize or avocado pollen diets) and polyfloral (using five types of pollen: Persea americana Mill., Zea mays L., Melampodium perfoliatum Cav., Drymaria villosa Cham Schltdl., and Lopezia racemosa Cav.) on their survival, body condition (controlled density, head mass, and development of hypopharyngeal glands; protein content in hemolymph), and immune response [lytic activity and activity of prophenoloxidase in the hemolymph (proPO)]. Corbicular pollen of P. americana had the highest protein content, followed by the corbicular pollen of Z. mays, M. perfoliatum, D. villosa, and L. racemosa. Polyfloral diet seems to be better for A. mellifera than the monofloral maize and avocado. Bees fed polyfloral pollen diet showed a high content of protein in the hemolymph in comparison with that fed maize or avocado pollen diets. Bees fed polyfloral and avocado pollen diet had the highest lytic activity but showed a decrease in proPO activity. In conclusion, polyfloral diets seem to be better for A. mellifera than the monofloral maize and avocado.
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Affiliation(s)
- Venecia Quesada-Béjar
- Facultad de Agrobiología, Univ Michoacana de San Nicolás de Hidalgo, Uruapan, Michoacán, México.
| | - Jorge Contreras-Garduño
- Escuela Nacional de Estudios Superiores, Univ Autónoma de México, Morelia, Michoacán, México
| | - L Karina Adame Calvillo
- Facultad de Agrobiología, Univ Michoacana de San Nicolás de Hidalgo, Uruapan, Michoacán, México
| | - Eduardo Cuevas García
- Facultad de Biología, Univ Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, México
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21
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Tuerlings T, Buydens L, Smagghe G, Piot N. The impact of mass-flowering crops on bee pathogen dynamics. Int J Parasitol Parasites Wildl 2022; 18:135-147. [PMID: 35586790 PMCID: PMC9108762 DOI: 10.1016/j.ijppaw.2022.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 04/29/2022] [Accepted: 05/01/2022] [Indexed: 11/24/2022]
Abstract
Nearly two fifths of the Earth's land area is currently used for agriculture, substantially impacting the environment and ecosystems. Besides the direct impact through land use change, intensive agriculture can also have an indirect impact, for example by changing wildlife epidemiology. We review here the potential effects of mass-flowering crops (MFCs), which are rapidly expanding in global cropping area, on the epidemiology of known pathogens in bee pollinators. We bring together the fifty MFCs with largest global area harvested and give an overview of their pollination dependency as well as their impact on bee pollinators. When in bloom these crops provide an abundance of flowers, which can provide nutrition for bees and increase bee reproduction. After their short bloom peak, however, the fields turn into green deserts. These big changes in floral availability strongly affect the plant-pollinator network, which in turn affects the pathogen transmission network, mediated by shared flowers. We address this dual role of flowers provided by MFCs, serving as nutritional resources as well as pathogen transmission spots, and bring together the current knowledge to assess how MFCs could affect pathogen prevalence in bee pollinator communities.
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Affiliation(s)
| | | | - Guy Smagghe
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Coupure links 653, Ghent University, Ghent, Belgium
| | - Niels Piot
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Coupure links 653, Ghent University, Ghent, Belgium
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22
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Wintermantel D, Pereira-Peixoto MH, Warth N, Melcher K, Faller M, Feurer J, Allan MJ, Dean R, Tamburini G, Knauer AC, Schwarz JM, Albrecht M, Klein AM. Flowering resources modulate the sensitivity of bumblebees to a common fungicide. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 829:154450. [PMID: 35276144 DOI: 10.1016/j.scitotenv.2022.154450] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/12/2022] [Accepted: 03/06/2022] [Indexed: 06/14/2023]
Abstract
Bees are exposed to various stressors, including pesticides and lack of flowering resources. Despite potential interactions between these stressors, the impacts of pesticides on bees are generally assumed to be consistent across bee-attractive crops, and regulatory risk assessments of pesticides neglect interactions with flowering resources. Furthermore, impacts of fungicides on bees are rarely examined in peer-reviewed studies, although these are often the pesticides that bees are most exposed to. In a full-factorial semi-field experiment with 39 large flight cages, we assessed the single and combined impacts of the globally used azoxystrobin-based fungicide Amistar® and three types of flowering resources (Phacelia, buckwheat, and a floral mix) on Bombus terrestris colonies. Although Amistar is classified as bee-safe, Amistar exposure through Phacelia monocultures reduced adult worker body mass and colony growth (including a 55% decline in workers and an 88% decline in males), while the fungicide had no impact on colonies in buckwheat or the floral mix cages. Furthermore, buckwheat monocultures hampered survival and fecundity irrespective of fungicide exposure. This shows that bumblebees require access to complementary flowering species to gain both fitness and fungicide tolerance and that Amistar impacts are flowering resource-dependent. Our findings call for further research on how different flowering plants affect bees and their pesticide tolerance to improve guidelines for regulatory pesticide risk assessments and inform the choice of plants that are cultivated to safeguard pollinators.
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Affiliation(s)
- Dimitry Wintermantel
- University of Freiburg, Nature Conservation and Landscape Ecology, Freiburg, Germany.
| | | | - Nadja Warth
- University of Freiburg, Nature Conservation and Landscape Ecology, Freiburg, Germany
| | - Kristin Melcher
- University of Freiburg, Nature Conservation and Landscape Ecology, Freiburg, Germany
| | - Michael Faller
- University of Freiburg, Nature Conservation and Landscape Ecology, Freiburg, Germany
| | - Joachim Feurer
- University of Freiburg, Nature Conservation and Landscape Ecology, Freiburg, Germany
| | | | - Robin Dean
- Red Beehive Company, Bishops Waltham, United Kingdom
| | - Giovanni Tamburini
- University of Bari, Department of Soil, Plant and Food Sciences (DiSSPA - Entomology), Bari, Italy
| | - Anina C Knauer
- Agroscope, Agroecology and Environment, Zurich, Switzerland
| | | | | | - Alexandra-Maria Klein
- University of Freiburg, Nature Conservation and Landscape Ecology, Freiburg, Germany
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23
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Lehmann DM. Protocol for Initiating and Monitoring Bumble Bee Microcolonies with Bombus impatiens (Hymenoptera: Apidae). Bio Protoc 2022; 12:e4451. [PMID: 35864899 PMCID: PMC9257840 DOI: 10.21769/bioprotoc.4451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 05/22/2022] [Accepted: 05/25/2022] [Indexed: 12/29/2022] Open
Abstract
Populations of some bumble bee species are in decline, prompting the need to better understand bumble bee biology and for assessing the effects of environmental stressors on these important pollinators. Microcolonies have been successfully used for investigating a range of endpoints, including behavior, gut microbiome, nutrition, development, pathogens, and the effects of pesticide exposure on bumble bee health. Here, we present a step-by-step protocol for initiating, maintaining, and monitoring microcolonies with Bombus impatiens . This protocol has been successfully used in two pesticide exposure-effects studies and can be easily expanded to investigate other aspects of bumble bee biology.
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Affiliation(s)
- David M. Lehmann
- Center for Public Health and Environmental Assessment (CPHEA), Health and Environmental Effects Assessment Division, Integrated Health Assessment Branch, U.S. - Environmental Protection Agency, Research Triangle Park, NC, 27711, USA
,
*For correspondence:
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24
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Fowler AE, Sadd BM, Bassingthwaite T, Irwin RE, Adler LS. Consuming sunflower pollen reduced pathogen infection but did not alter measures of immunity in bumblebees. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210160. [PMID: 35491606 PMCID: PMC9058531 DOI: 10.1098/rstb.2021.0160] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 11/23/2021] [Indexed: 11/12/2022] Open
Abstract
Certain diets can benefit bee health by reducing pathogens, but the mechanism(s) driving these medicinal effects are largely unexplored. Recent research found that sunflower (Helianthus annuus) pollen reduces the gut pathogen Crithidia bombi in the common eastern bumblebee (Bombus impatiens). Here, we tested the effects of sunflower pollen and infection on two bee immune metrics to determine whether sunflower pollen diet drives changes in host immunity that can explain this medicinal effect. Bees were infected with C. bombi or not and given either sunflower or wildflower pollen. Subsequently, bees received a benign immune challenge or were left naive to test the induced and constitutive immune responses, respectively. We measured haemolymph phenoloxidase activity, involved in the melanization cascade, and antibacterial activity. Sunflower pollen reduced C. bombi infection, but we found no significant pollen diet effect on either immune measure. Phenoloxidase activity was also not affected by C. bombi infection status; however, uninfected bees were more likely to have measurable constitutive antibacterial activity, while infected bees had higher induced antibacterial activity. Overall, we found that sunflower pollen does not significantly affect the immune responses we measured, suggesting that the mechanisms underlying its medicinal effect do not involve these bee immune parameters. This article is part of the theme issue 'Natural processes influencing pollinator health: from chemistry to landscapes'.
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Affiliation(s)
- Alison E. Fowler
- Department of Biology, University of Massachusetts Amherst, 221 Morrill Science Center South, 611 North Pleasant Street, Amherst, MA 01003, USA
| | - Ben M. Sadd
- School of Biological Sciences, Illinois State University, Normal, IL 61790, USA
| | - Toby Bassingthwaite
- School of Biological Sciences, Illinois State University, Normal, IL 61790, USA
| | - Rebecca E. Irwin
- Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695, USA
| | - Lynn S. Adler
- Department of Biology, University of Massachusetts Amherst, 221 Morrill Science Center South, 611 North Pleasant Street, Amherst, MA 01003, USA
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25
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Weitekamp CA, Koethe RW, Lehmann DM. A Comparison of Pollen and Syrup Exposure Routes in Bombus impatiens (Hymenoptera: Apidae) Microcolonies: Implications for Pesticide Risk Assessment. ENVIRONMENTAL ENTOMOLOGY 2022; 51:613-620. [PMID: 35512429 PMCID: PMC9926532 DOI: 10.1093/ee/nvac026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Indexed: 06/14/2023]
Abstract
Bumble bees are important pollinators for both native plants and managed agricultural systems. Accumulating evidence has shown that pesticides, including neonicotinoids, can have a range of adverse effects on bumble bee health. Most laboratory studies that assess the effects of chronic neonicotinoid exposure on bumble bees use syrup as the delivery vehicle, rather than pollen. However, in the field, it is likely that bumble bees are exposed to neonicotinoids in both nectar (syrup) and pollen. To examine the potential for different effects based on the vehicle, we compared two studies of chronic exposure to the neonicotinoid acetamiprid in Bombus impatiens microcolonies. We examined correlations between microcolony endpoints and identified associations between the timing of colony pollen and syrup consumption and drone production. Furthermore, in line with previous results, we found that average drone weight was affected at a range of doses only when microcolonies were exposed to acetamiprid via pollen. In general, our analyses point to the importance of the treatment vehicle and suggest that critical effects on developing brood could be missed when neonicotinoid exposure occurs only through syrup.
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Affiliation(s)
- Chelsea A. Weitekamp
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC
| | - Robert W. Koethe
- Region 1 Office, Land Chemicals and Redevelopment Division RCRA, Waste Management and Pesticides Section, U.S. Environmental Protection Agency, Boston, MA
| | - David M. Lehmann
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC
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26
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El-Seedi HR, Ahmed HR, El-Wahed AAA, Saeed A, Algethami AF, Attia NF, Guo Z, Musharraf SG, Khatib A, Alsharif SM, Naggar YA, Khalifa SAM, Wang K. Bee Stressors from an Immunological Perspective and Strategies to Improve Bee Health. Vet Sci 2022; 9:vetsci9050199. [PMID: 35622727 PMCID: PMC9146872 DOI: 10.3390/vetsci9050199] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/11/2022] [Accepted: 04/14/2022] [Indexed: 02/06/2023] Open
Abstract
Honeybees are the most prevalent insect pollinator species; they pollinate a wide range of crops. Colony collapse disorder (CCD), which is caused by a variety of biotic and abiotic factors, incurs high economic/ecological loss. Despite extensive research to identify and study the various ecological stressors such as microbial infections, exposure to pesticides, loss of habitat, and improper beekeeping practices that are claimed to cause these declines, the deep understanding of the observed losses of these important insects is still missing. Honeybees have an innate immune system, which includes physical barriers and cellular and humeral responses to defend against pathogens and parasites. Exposure to various stressors may affect this system and the health of individual bees and colonies. This review summarizes and discusses the composition of the honeybee immune system and the consequences of exposure to stressors, individually or in combinations, on honeybee immune competence. In addition, we discuss the relationship between bee nutrition and immunity. Nutrition and phytochemicals were highlighted as the factors with a high impact on honeybee immunity.
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Affiliation(s)
- Hesham R. El-Seedi
- Pharmacognosy Group, Department of Pharmaceutical Biosciences, Uppsala University, Biomedical Centre, P.O. Box 591, SE 751 24 Uppsala, Sweden
- International Research Center for Food Nutrition and Safety, Jiangsu University, Zhenjiang 212013, China
- International Joint Research Laboratory of Intelligent Agriculture and Agri-Products Processing (Jiangsu University), Jiangsu Education Department, Nanjing 210024, China
- Department of Chemistry, Faculty of Science, Menoufia University, Shebin El-Kom 32512, Egypt;
- Correspondence: (H.R.E.-S.); (K.W.); Tel.: +46-700-43-43-43 (H.R.E.-S.); +86-10-62596625 (K.W.)
| | - Hanan R. Ahmed
- Department of Chemistry, Faculty of Science, Menoufia University, Shebin El-Kom 32512, Egypt;
| | - Aida A. Abd El-Wahed
- Department of Bee Research, Plant Protection Research Institute, Agricultural Research Centre, Giza 12627, Egypt;
| | - Aamer Saeed
- Department of Chemistry, Quaid-I-Azam University, Islamabad 45320, Pakistan;
| | - Ahmed F. Algethami
- Al nahal al jwal Foundation Saudi Arabia, P.O. Box 617, Al Jumum, Makkah 21926, Saudi Arabia;
| | - Nour F. Attia
- Chemistry Division, National Institute of Standards, 136, Giza 12211, Egypt;
| | - Zhiming Guo
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China;
| | - Syed G. Musharraf
- H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan;
| | - Alfi Khatib
- Department of Pharmaceutical Chemistry, Kulliyyah of Pharmacy, International Islamic Univetsity Malaysia, Kuantan 25200, Malaysia;
- Faculty of Pharmacy, Universitas Airlangga, Surabaya 60155, Indonesia
| | - Sultan M. Alsharif
- Biology Department, Faculty of Science, Taibah University, Al Madinah 887, Saudi Arabia;
| | - Yahya Al Naggar
- Zoology Department, Faculty of Science, Tanta University, Tanta 31527, Egypt;
- General Zoology, Institute for Biology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle, Germany
| | - Shaden A. M. Khalifa
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE 106 91 Stockholm, Sweden;
| | - Kai Wang
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing 100093, China
- Correspondence: (H.R.E.-S.); (K.W.); Tel.: +46-700-43-43-43 (H.R.E.-S.); +86-10-62596625 (K.W.)
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27
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Pang C, Dong K, Guo Y, Ding G, Lu Y, Guo Z, Wu J, Huang J. Effects of Three Types of Pollen on the Growth and Development of Honey Bee Larvae (Hymenoptera, Apidae). Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.870081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Pollen serves as an essential protein source for honey bee larvae. The nutrients in pollen greatly influence larval growth and development. Here, the survival, prepupal weight, developmental stage, pollen digestibility and midgut cells in honey bee (Apis mellifera L.) larvae were evaluated by performing in vitro and 5-ethynyl-2′-deoxyuridine (EdU) assays on larvae reared on three single pollens (Brassica napus L., Armeniaca sibirica L., and Pyrus bretschneideri Rehd.) and a pollen mixture (mixture of the three pollens in equal proportions). The results showed that the survival rate of larvae fed 10 mg of rape pollen was lowest (P < 0.05), but there were no notable differences in the survival rate among the groups receiving the other types and doses of pollen (P > 0.05). The prepupal weight of larvae fed apricot pollen was significantly lower than those of the other groups (P < 0.05). The digestibility of rape pollen and the pollen mixture were dramatically higher than those of apricot and pear pollen (P < 0.05). Pear and mixed pollen exerted negative effects on the nuclear area of midgut cells in the early larval stage (P < 0.05). In conclusion, detection of larval midgut cells using the EdU assay might be an effective method to assess the pollen nutritive value in honey bees. Compared to apricot and pear pollen, rape pollen was more beneficial in larval honey bee growth and development.
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Gekière A, Semay I, Gérard M, Michez D, Gerbaux P, Vanderplanck M. Poison or Potion: Effects of Sunflower Phenolamides on Bumble Bees and Their Gut Parasite. BIOLOGY 2022; 11:545. [PMID: 35453744 PMCID: PMC9030180 DOI: 10.3390/biology11040545] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 03/28/2022] [Accepted: 03/30/2022] [Indexed: 11/29/2022]
Abstract
Specific floral resources may help bees to face environmental challenges such as parasite infection, as recently shown for sunflower pollen. Whereas this pollen diet is known to be unsuitable for the larval development of bumble bees, it has been shown to reduce the load of a trypanosomatid parasite (Crithidia bombi) in the bumble bee gut. Recent studies suggested it could be due to phenolamides, a group of compounds commonly found in flowering plants. We, therefore, decided to assess separately the impacts of sunflower pollen and its phenolamides on a bumble bee and its gut parasite. We fed Crithidia-infected and -uninfected microcolonies of Bombus terrestris either with a diet of willow pollen (control), a diet of sunflower pollen (natural diet) or a diet of willow pollen supplemented with sunflower phenolamides (supplemented diet). We measured several parameters at both microcolony (i.e., food collection, parasite load, brood development and stress responses) and individual (i.e., fat body content and phenotypic variation) levels. As expected, the natural diet had detrimental effects on bumble bees but surprisingly, we did not observe any reduction in parasite load, probably because of bee species-specific outcomes. The supplemented diet also induced detrimental effects but by contrast to our a priori hypothesis, it led to an increase in parasite load in infected microcolonies. We hypothesised that it could be due to physiological distress or gut microbiota alteration induced by phenolamide bioactivities. We further challenged the definition of medicinal effects and questioned the way to assess them in controlled conditions, underlining the necessity to clearly define the experimental framework in this research field.
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Affiliation(s)
- Antoine Gekière
- Laboratoire de Zoologie, Research Institute for Biosciences, University of Mons, 7000 Mons, Belgium;
| | - Irène Semay
- Organic Synthesis and Mass Spectrometry Laboratory, Research Institute for Biosciences, University of Mons, 7000 Mons, Belgium; (I.S.); (P.G.)
| | - Maxence Gérard
- Insect Lab., Division of Functional Morphology, Department of Zoology, Stockholm University, 11418 Stockholm, Sweden;
| | - Denis Michez
- Laboratoire de Zoologie, Research Institute for Biosciences, University of Mons, 7000 Mons, Belgium;
| | - Pascal Gerbaux
- Organic Synthesis and Mass Spectrometry Laboratory, Research Institute for Biosciences, University of Mons, 7000 Mons, Belgium; (I.S.); (P.G.)
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29
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Memory-guided foraging and landscape design interact to determine ecosystem services. J Theor Biol 2022; 534:110958. [PMID: 34748733 DOI: 10.1016/j.jtbi.2021.110958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 10/22/2021] [Accepted: 10/31/2021] [Indexed: 11/23/2022]
Abstract
Many studies examine how the landscape affects memory-informed movement patterns, but very few examine how memory-informed foragers influence the landscape. This reverse relationship is an important factor in preventing the continued decline of many ecosystem services. We investigate this question in the context of crop pollination services by wild bees, a critical ecosystem service that is in steep decline. Many studies suggest that adding wild flower patches near crops can result in higher crop pollination services, but specific advice pertaining to the optimal location and density of these wild flower patches is lacking, as well as any estimate of the expected change in crop pollination services. In this work, we seek to understand what is the optimal placement of a flower patch relative to a single crop field, during crop bloom and considering spatial factors alone. We develop an individual based model of memory-based foraging by bumble bees to simulate bee movement from a single nest while the crop is in bloom, and measure the resulting crop pollination services. We consider a single crop field enhanced with a wild flower patch in a variable location, and measure crop flower visitation over the course of a single day. We analyze the pollination intensity and spatial distribution of flower visits to determine optimal wild flower patch placement for an isolated crop field. We find that the spatial arrangement of crop and wild flower patch have a significant effect on the number of crop flower visits, and that these effects arise from the memory-informed foraging pattern. The most effective planting locations are either in the centre of the crop field or on the far side of the crop field, away from the single bumble bee nest.
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30
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Barraud A, Barascou L, Lefebvre V, Sene D, Le Conte Y, Alaux C, Grillenzoni FV, Corvucci F, Serra G, Costa C, Vanderplanck M, Michez D. Variations in Nutritional Requirements Across Bee Species. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2022. [DOI: 10.3389/fsufs.2022.824750] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
With 2,000 species currently recorded in Europe, bees are a highly diversified and efficient group of pollinating insects. They obtain their nutrients from nectar and pollen of flowers. However, the chemical composition of these resources, especially of pollen (e.g., protein, lipid, amino acids, fatty acids, or sterol content), is highly variable among plant species. While it is well-known that bees show interspecific variation in their floral choices, there is a lack of information on the nutritional requirements of different bee species. We therefore developed original experiments in laboratory conditions to evaluate the interspecific variations in bee nutritional requirements. We analyzed the chemical content of eight pollen blends, different in terms of protein, lipid, amino acids, and sterols total concentration and profiles. Each pollen blend was provided to four different bee model species: honey bees (Apis mellifera), bumblebees (Bombus terrestris), mason bees (Osmia bicornis and Osmia cornuta). For each species, specific protocols were used to monitor their development (e.g., weight, timing, survival) and resource collection. Overall, we found that the nutritional requirements across those species are different, and that a low-quality diet for one species is not necessarily low-quality for another one. While honey bees are negatively impacted by diets with a high protein content (~40%), bumblebees and mason bees develop normally on these diets but struggle on diets with a low total amino acid and sterol content, specifically with low concentrations of 24-methylenecholesterol and β-sitosterol. Overall, our study supports the need of conserving and/or introducing plant diversity into managed ecosystems to meet the natural nutritional preferences of bees at species and community level.
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31
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Honey bees and climate explain viral prevalence in wild bee communities on a continental scale. Sci Rep 2022; 12:1904. [PMID: 35115568 PMCID: PMC8814194 DOI: 10.1038/s41598-022-05603-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 12/23/2021] [Indexed: 01/10/2023] Open
Abstract
Viruses are omnipresent, yet the knowledge on drivers of viral prevalence in wild host populations is often limited. Biotic factors, such as sympatric managed host species, as well as abiotic factors, such as climatic variables, are likely to impact viral prevalence. Managed and wild bees, which harbor several multi-host viruses with a mostly fecal-oral between-species transmission route, provide an excellent system with which to test for the impact of biotic and abiotic factors on viral prevalence in wild host populations. Here we show on a continental scale that the prevalence of three broad host viruses: the AKI-complex (Acute bee paralysis virus, Kashmir bee virus and Israeli acute paralysis virus), Deformed wing virus, and Slow bee paralysis virus in wild bee populations (bumble bees and solitary bees) is positively related to viral prevalence of sympatric honey bees as well as being impacted by climatic variables. The former highlights the need for good beekeeping practices, including Varroa destructor management to reduce honey bee viral infection and hive placement. Furthermore, we found that viral prevalence in wild bees is at its lowest at the extreme ends of both temperature and precipitation ranges. Under predicted climate change, the frequency of extremes in precipitation and temperature will continue to increase and may hence impact viral prevalence in wild bee communities.
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32
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Giacomini JJ, Moore N, Adler LS, Irwin RE. Sunflower pollen induces rapid excretion in bumble bees: Implications for host-pathogen interactions. JOURNAL OF INSECT PHYSIOLOGY 2022; 137:104356. [PMID: 35016876 DOI: 10.1016/j.jinsphys.2022.104356] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 12/08/2021] [Accepted: 01/05/2022] [Indexed: 06/14/2023]
Abstract
Host diet can have a profound effect on host-pathogen interactions, including indirect effects on pathogens mediated through host physiology. In bumble bees (Bombus impatiens), the consumption of sunflower (Helianthus annuus) pollen dramatically reduces infection by the gut protozoan pathogen Crithidia bombi. One hypothesis for the medicinal effect of sunflower pollen is that consumption changes host gut physiological function, causing rapid excretion that flushes C. bombi from the system. We tested the effect of pollen diet and C. bombi infection on gut transit properties using a 2x2 factorial experiment in which bees were infected with C. bombi or not and fed sunflower or wildflower pollen diet. We measured several non-mutually exclusive physiological processes that underlie the insect excretory system, including gut transit time, bi-hourly excretion rate, the total number of excretion events and the total volume of excrement. Sunflower pollen significantly reduced gut transit time in uninfected bees, and increased the total number of excretion events and volume of excrement by 66 % and 68 %, respectively, in both infected and uninfected bees. Here we show that a sunflower pollen diet can affect host physiology gut function, causing more rapid and greater excretion. These results provide important insight into a mechanism that could underlie the medicinal effect of sunflower pollen for bumble bees.
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Affiliation(s)
- Jonathan J Giacomini
- Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695 USA.
| | - Nicholas Moore
- Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695 USA
| | - Lynn S Adler
- Department of Biology, University of Massachusetts Amherst, Amherst, MA 01003 USA
| | - Rebecca E Irwin
- Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695 USA
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33
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Straub L, Minnameyer A, Camenzind D, Kalbermatten I, Tosi S, Van Oystaeyen A, Wäckers F, Neumann P, Strobl V. Thiamethoxam as an inadvertent anti-aphrodisiac in male bees. Toxicol Rep 2022; 9:36-45. [PMID: 34987978 PMCID: PMC8693414 DOI: 10.1016/j.toxrep.2021.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 12/03/2021] [Accepted: 12/04/2021] [Indexed: 12/03/2022] Open
Abstract
There is consensus that neonicotinoids can impact non-target animal fertility. Thiamethoxam reduced both mating success and sperm physiology in bumblebees. Queens mated by exposed males had 50% less total living sperm in their spermatheca. Thiamethoxam may act as anti-aphrodisiac, thereby limiting conservation efforts.
Sexual reproduction is common to almost all multi-cellular organisms and can be compromised by environmental pollution, thereby affecting entire populations. Even though there is consensus that neonicotinoid insecticides can impact non-target animal fertility, their possible impact on male mating success is currently unknown in bees. Here, we show that sublethal exposure to a neonicotinoid significantly reduces both mating success and sperm traits of male bumblebees. Sexually mature male Bombus terrestris exposed to a field-realistic concentration of thiamethoxam (20 ng g−1) or not (controls) were mated with virgin gynes in the laboratory. The results confirm sublethal negative effects of thiamethoxam on sperm quantity and viability. While the latency to mate was reduced, mating success was significantly impaired in thiamethoxam-exposed males by 32% probably due to female choice. Gynes mated by exposed males revealed impaired sperm traits compared to their respective controls, which may lead to severe constraints for colony fitness. Our laboratory findings demonstrate for the first time that neonicotinoid insecticides can negatively affect male mating success in bees. Given that holds true for the field, this provides a plausible mechanism contributing to declines of wild bee populations globally. The widespread prophylactic use of neonicotinoids may therefore have previously overlooked inadvertent anti-aphrodisiac effects on non-target animals, thereby limiting conservation efforts.
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Affiliation(s)
- Lars Straub
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland.,Agroscope, Swiss Bee Research Centre, Bern, Switzerland
| | - Angela Minnameyer
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Domenic Camenzind
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | | | - Simone Tosi
- Department of Agricultural, Forest, and Food Sciences, University of Turin, Italy
| | | | | | - Peter Neumann
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland.,Agroscope, Swiss Bee Research Centre, Bern, Switzerland
| | - Verena Strobl
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
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34
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Watrobska CM, Ramos Rodrigues A, Arce AN, Clarke J, Gill RJ. Pollen Source Richness May Be a Poor Predictor of Bumblebee ( Bombus terrestris) Colony Growth. FRONTIERS IN INSECT SCIENCE 2021; 1:741349. [PMID: 38468876 PMCID: PMC10926443 DOI: 10.3389/finsc.2021.741349] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 10/27/2021] [Indexed: 03/13/2024]
Abstract
Agricultural intensification has drastically altered foraging landscapes for bees, with large-scale crop monocultures associated with floral diversity loss. Research on bumblebees and honeybees has shown individuals feeding on pollen from a low richness of floral sources can experience negative impacts on health and longevity relative to higher pollen source richness of similar protein concentrations. Florally rich landscapes are thus generally assumed to better support social bees. Yet, little is known about whether the effects of reduced pollen source richness can be mitigated by feeding on pollen with higher crude protein concentration, and importantly how variation in diet affects whole colony growth, rearing decisions and sexual production. Studying queen-right bumblebee (Bombus terrestris) colonies, we monitored colony development under a polyfloral pollen diet or a monofloral pollen diet with 1.5-1.8 times higher crude protein concentration. Over 6 weeks, we found monofloral colonies performed better for all measures, with no apparent long-term effects on colony mass or worker production, and a higher number of pupae in monofloral colonies at the end of the experiment. Unexpectedly, polyfloral colonies showed higher mortality, and little evidence of any strategy to counteract the effects of reduced protein; with fewer and lower mass workers being reared, and males showing a similar trend. Our findings (i) provide well-needed daily growth dynamics of queenright colonies under varied diets, and (ii) support the view that pollen protein content in the foraging landscape rather than floral species richness per se is likely a key driver of colony health and success.
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Affiliation(s)
| | | | | | | | - Richard J. Gill
- Department of Life Sciences, Imperial College London, Silwood Park Campus, London, United Kingdom
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Sculfort O, Gérard M, Gekière A, Nonclercq D, Gerbaux P, Duez P, Vanderplanck M. Specialized Metabolites in Floral Resources: Effects and Detection in Buff-Tailed Bumblebees. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.669352] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The selection of appropriate food resources by bees is a critical aspect for the maintenance of their populations, especially in the current context of global change and pollinator decline. Wild bees have a sophisticated ability to forage selectively on specific resources, and can assess the quality of pollen using contact chemosensory perception (taste). While numerous studies have investigated the detection of pollen macronutrients in bees and their impact on bee health and reproductive success, only a few studies have described the gustatory responses of bees toward specialized metabolites. In addition, these studies mostly focused on the response to nectar and neglected pollen, which is the main food resource for both bee imagines and larvae. Whether bees have the ability to detect specialized toxic metabolites in pollen and then rapidly adapt their foraging behavior to avoid them is very little studied. In this study, we tested whether pollen specialized metabolites affect bumblebees at both the micro-colony and individual levels (i.e., bioassays using supplemented pollen), and whether foragers detect these specialized metabolites and potentially display an avoidance behavior (i.e., preference tests using supplemented syrup). Bumblebees were fed with either amygdalin-, scopolamine- or sinigrin-supplemented pollen diets in ratios that mimic 50%, 100%, and 200% of naturally occurring concentrations. We found no effect of these specialized metabolites on resource collection, reproductive success and stress response at the micro-colony level. At the individual level, bumblebees fed on 50%-amygdalin or 50%-scopolamine diets displayed the highest scores for damage to their digestive systems. Interestingly, during the preference tests, the solution with 50%-scopolamine displayed a phagostimulatory activity, whereas solution with 50%-amygdalin had a deterrent effect and could trigger an active avoidance behavior in bumblebees, with a faster proboscis retraction. Our results suggest that regulation of toxin intake is not as well-established and effective as the regulation of nutrient intake in bees. Bees are therefore not equally adapted to all specialized pollen metabolites that they can come into contact with.
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Using Matching Traits to Study the Impacts of Land-Use Intensification on Plant-Pollinator Interactions in European Grasslands: A Review. INSECTS 2021; 12:insects12080680. [PMID: 34442246 PMCID: PMC8396669 DOI: 10.3390/insects12080680] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/17/2021] [Accepted: 07/23/2021] [Indexed: 11/29/2022]
Abstract
Simple Summary Permanent grasslands are main habitats for many plant species and pollinators. Their destruction as well as their intensification has a major impact on plant and pollinator biodiversity, which has a cascading effect on pollination. However, we lack an understanding of these effects, thereby limiting our ability to predict them. In this review, we synthesised the literature on the mechanisms behind this cascade to provide new insights into the relationship between land-use intensification and pollination. By matching functional traits that mediate the relationship between the two trophic levels, we identified major knowledge gaps about how land-use intensification affects plant–pollinator interactions and how it favours plants with generalised floral traits, which are likely harmful to pollination. Abstract Permanent grasslands are suitable habitats for many plant and animal species, among which are pollinating insects that provide a wide range of ecosystem services. A global crisis in pollination ecosystem service has been highlighted in recent decades, partly the result of land-use intensification. At the grassland scale, however, the underlying mechanisms of land-use intensification that affect plant–pollinator interactions and pollination remain understudied. In this review, we first synthesise the literature to provide new insights into the relationships between land-use intensification and pollination by using matching community and interaction traits. We then identify knowledge gaps and summarise how land-use intensification of grassland influences floral traits that may in turn be associated with modifications to pollinator matching traits. Last, we summarise how these modifications may affect pollination function on permanent grasslands. Overall, land-use intensification may lead to a shift in flower colour, a decrease in mean nectar tube depth and a decrease in reward production and pollen quality at the community level. This, in turn, may generate a decrease in pollinator mouthparts length and body size, that may favour pollinators that require a low amount of floral reward. We found no study citing the effect of land-use intensification on volatile organic compounds emitted by flowers despite the importance of these molecules in pollinator community composition. Overall, our review highlighted major knowledge gaps about the effects of land-use intensification on plant–pollinator interactions, and suggests that land-use intensification could favour plants with generalised floral traits that adversely affect pollination.
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Giacomini JJ, Connon SJ, Marulanda D, Adler LS, Irwin RE. The costs and benefits of sunflower pollen diet on bumble bee colony disease and health. Ecosphere 2021. [DOI: 10.1002/ecs2.3663] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Jonathan J. Giacomini
- Department of Applied Ecology North Carolina State University Raleigh North Carolina 27695 USA
| | - Sara J. Connon
- Department of Applied Ecology North Carolina State University Raleigh North Carolina 27695 USA
| | - Daniel Marulanda
- Department of Applied Ecology North Carolina State University Raleigh North Carolina 27695 USA
| | - Lynn S. Adler
- Department of Biology University of Massachusetts Amherst Amherst Massachusetts 01003 USA
| | - Rebecca E. Irwin
- Department of Applied Ecology North Carolina State University Raleigh North Carolina 27695 USA
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Vesga P, Augustiny E, Keel C, Maurhofer M, Vacheron J. Phylogenetically closely related pseudomonads isolated from arthropods exhibit differential insect-killing abilities and genetic variations in insecticidal factors. Environ Microbiol 2021; 23:5378-5394. [PMID: 34190383 PMCID: PMC8519069 DOI: 10.1111/1462-2920.15623] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 05/12/2021] [Accepted: 06/02/2021] [Indexed: 01/07/2023]
Abstract
Strains belonging to the Pseudomonas protegens and Pseudomonas chlororaphis species are able to control soilborne plant pathogens and to kill pest insects by producing virulence factors such as toxins, chitinases, antimicrobials or two‐partner secretion systems. Most insecticidal Pseudomonas described so far were isolated from roots or soil. It is unknown whether these bacteria naturally occur in arthropods and how they interact with them. Therefore, we isolated P. protegens and P. chlororaphis from various healthy insects and myriapods, roots and soil collected in an agricultural field and a neighbouring grassland. The isolates were compared for insect killing, pathogen suppression and host colonization abilities. Our results indicate that neither the origin of isolation nor the phylogenetic position mirror the degree of insecticidal activity. Pseudomonas protegens strains appeared homogeneous regarding phylogeny, biocontrol and insecticidal capabilities, whereas P. chlororaphis strains were phylogenetically and phenotypically more heterogenous. A phenotypic and genomic analysis of five closely related P. chlororaphis isolates displaying varying levels of insecticidal activity revealed variations in genes encoding insecticidal factors that may account for the reduced insecticidal activity of certain isolates. Our findings point towards an adaption to insects within closely related pseudomonads and contribute to understand the ecology of insecticidal Pseudomonas.
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Affiliation(s)
- Pilar Vesga
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland.,Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Eva Augustiny
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Christoph Keel
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Monika Maurhofer
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Jordan Vacheron
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
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Ruedenauer FA, Biewer NW, Nebauer CA, Scheiner M, Spaethe J, Leonhardt SD. Honey Bees Can Taste Amino and Fatty Acids in Pollen, but Not Sterols. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.684175] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The nutritional composition of food is often complex as resources contain a plethora of different chemical compounds, some of them more, some less meaningful to consumers. Plant pollen, a major food source for bees, is of particular importance as it comprises nearly all macro- and micronutrients required by bees for successful development and reproduction. However, perceiving and evaluating all nutrients may be tedious and impair quick foraging decisions. It is therefore likely that nutrient perception is restricted to specific nutrients or nutrient groups. To better understand the role of taste in pollen quality assessment by bees we investigated nutrient perception in the Western honey bee, Apis mellifera. We tested if the bees were able to perceive concentration differences in amino acids, fatty acids, and sterols, three highly important nutrient groups in pollen, via antennal reception. By means of proboscis extension response (PER) experiments with chemotactile stimulation, we could show that honey bees can distinguish between pollen differing in amino and fatty acid concentration, but not in sterol concentration. Bees were also not able to perceive sterols when presented alone. Our finding suggests that assessment of pollen protein and lipid content is prioritized over sterol content.
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Watrous KM, Costa CP, Diaz YR, Woodard SH. Flexibility in the Critical Period of Nutrient Sequestration in Bumble Bee Queens. Integr Org Biol 2021; 3:obab009. [PMID: 34104874 PMCID: PMC8179628 DOI: 10.1093/iob/obab009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Synopsis Bumble bee queens undergo a nutrient storage period prior to entering diapause wherein they sequester glycogen and lipids that are metabolized during overwintering. In the laboratory under optimal food availability conditions, the majority of nutrients are sequestered during the first few days of adulthood. However, if food resources are scarce during this narrow window of time, wild queen bumble bees might be limited in their ability to obtain adequate food resources for overwintering. Here we used a laboratory experiment to examine whether queen bumble bees exhibit flexibility in the timing of pre-overwintering nutrient sequestration, by limiting their access to either nectar (artificial) or pollen, the two primary foods for bumble bees, for varying periods of time. In response to these treatments, we quantified queen survival, changes in weight, and glycogen and lipids levels. We found evidence that queens are able to recuperate almost entirely from food resource limitation, with respect to nutrient storage, especially when it is experienced for shorter durations (up to 6 days). This study sheds light on how bumble bee queens are impacted by food resource availability at a critical life stage. Portuguese As abelhas rainhas do gênero Bombus armazenam nutrientes antes de entrarem em diapausa, sequestrando o glicogênio e os lipídios que serão metabolizados durante o inverno. Em condições ideais de disponibilidade de alimento no laboratório, a maioria dos nutrientes é sequestrada nos primeiros dias de vida adulta. No entanto, em condições de escassez de alimento na natureza, as rainhas podem sofrer limitações em sua capacidade de obter recursos para o inverno. Nesse contexto, em condições controladas, examinamos se as rainhas exibem variações no sequestro de nutrientes, limitando o acesso ao néctar (artificial) ou pólen, seus principais alimentos, em diferentes intervalos de tempo. Em resposta a esses tratamentos, quantificamos a taxa de sobrevivência das rainhas, as mudanças no peso e os níveis de glicogênio e lipídios. Encontramos evidências de que as rainhas são capazes de recuperar a capacidade de armazenar nutrientes quase inteiramente, especialmente em períodos mais curtos de escassez de alimento (até 6 dias). Este estudo lança luz sobre como as rainhas são afetadas pela variação na disponibilidade de recursos alimentares em um estágio crítico da vida. Spanish Las abejas reinas de generó Bombus, mejor conocidas como reinas de abejorro se someten a un período de almacenamiento de nutrientes antes de entrar en diapausa, en el cual secuestran glucógeno y lípidos que se metabolizan durante el invierno. En el laboratorio, en condiciones óptimas de disponibilidad de alimentos, la mayoría de los nutrientes se secuestran durante los primeros días de la edad adulta. Sin embargo, si los recursos alimenticios son escasos durante esta estrecha ventana de tiempo, las abejas reinas silvestres podrían verse limitadas en su capacidad para obtener recursos alimenticios adecuados para pasar el invierno. Aquí utilizamos un experimento de laboratorio para examinar si las abejas reinas exhiben flexibilidad en el momento del secuestro de nutrientes antes de la hibernación, al limitar su acceso al néctar (artificial) o al polen, los dos alimentos principales de los abejorros, durante períodos variables. En respuesta a estos tratamientos, cuantificamos la supervivencia de la reina, los cambios de peso y los niveles de glucógeno y lípidos. Encontramos evidencia de que las reinas pueden recuperarse casi por completo de la limitación de los recursos alimenticios, con respecto al almacenamiento de nutrientes, especialmente cuando se experimenta por períodos más cortos (hasta 6 días). Este estudio arroja luz sobre cómo las abejas reinas se ven afectadas por la disponibilidad de recursos alimenticios en una etapa crítica de la vida.
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Affiliation(s)
- Kristal M Watrous
- Department of Entomology, The University of California, Riverside, CA 92521, USA
| | - Claudinéia P Costa
- Department of Entomology, The University of California, Riverside, CA 92521, USA
| | - Yadira R Diaz
- Department of Entomology, The University of California, Riverside, CA 92521, USA
| | - S Hollis Woodard
- Department of Entomology, The University of California, Riverside, CA 92521, USA
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Vanderplanck M, Michez D, Albrecht M, Attridge E, Babin A, Bottero I, Breeze T, Brown M, Chauzat MP, Cini E, Costa C, De la Rua P, de Miranda J, Di Prisco G, Dominik C, Dzul D, Fiordaliso W, Gennaux S, Ghisbain G, Hodge S, Klein AM, Knapp J, Knauer A, Laurent M, Lefebvre V, Mänd M, Martinet B, Martinez-Lopez V, Medrzycki P, Pereira Peixoto MH, Potts S, Przybyla K, Raimets R, Rundlöf M, Schweiger O, Senapathi D, Serrano J, Stout J, Straw E, Tamburini G, Toktas Y, Gérard M. Monitoring bee health in European agro-ecosystems using wing morphology and fat bodies. ONE ECOSYSTEM 2021. [DOI: 10.3897/oneeco.6.e63653] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Current global change substantially threatens pollinators, which directly impacts the pollination services underpinning the stability, structure and functioning of ecosystems. Amongst these threats, many synergistic drivers, such as habitat destruction and fragmentation, increasing use of agrochemicals, decreasing resource diversity, as well as climate change, are known to affect wild and managed bees. Therefore, reliable indicators for pollinator sensitivity to such threats are needed. Biological traits, such as phenotype (e.g. shape, size and asymmetry) and storage reserves (e.g. fat body size), are important pollinator traits linked to reproductive success, immunity, resilience and foraging efficiency and, therefore, could serve as valuable markers of bee health and pollination service potential.
This data paper contains an extensive dataset of wing morphology and fat body content for the European honeybee (Apis mellifera) and the buff-tailed bumblebee (Bombus terrestris) sampled at 128 sites across eight European countries in landscape gradients dominated by two major bee-pollinated crops (apple and oilseed rape), before and after focal crop bloom and potential pesticide exposure. The dataset also includes environmental metrics of each sampling site, namely landscape structure and pesticide use. The data offer the opportunity to test whether variation in the phenotype and fat bodies of bees is structured by environmental factors and drivers of global change. Overall, the dataset provides valuable information to identify which environmental threats predominantly contribute to the modification of these traits.
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Descamps C, Boubnan N, Jacquemart AL, Quinet M. Growing and Flowering in a Changing Climate: Effects of Higher Temperatures and Drought Stress on the Bee-Pollinated Species Impatiens glandulifera Royle. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10050988. [PMID: 34063542 PMCID: PMC8156011 DOI: 10.3390/plants10050988] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 05/10/2021] [Accepted: 05/14/2021] [Indexed: 05/27/2023]
Abstract
Drought and higher temperatures caused by climate change are common stress conditions affecting plant growth and development. The reproductive phase is particularly sensitive to stress, but plants also need to allocate their limited resources to produce floral traits and resources to attract pollinators. We investigated the physiological and floral consequences of abiotic stress during the flowering period of Impatiens glandulifera, a bee-pollinated species. Plants were exposed to three temperatures (21, 24, 27 °C) and two watering regimes (well-watered, water stress) for 3 weeks. Not all parameters measured responded in the same manner to drought and/or heat stress. Drought stress induced leaf senescence, decreasing leaf number by 15-30% depending on growth temperature. Drought also reduced photosynthetic output, while temperature rise affected stomatal conductance. The number of flowers produced dropped 40-90% in response to drought stress, while higher temperatures shortened flower life span. Both stresses affected floral traits, but flower resources diminished in response to higher temperatures, with lower nectar volume and pollen protein content. We conclude that increased temperatures and drought stress, which are becoming more frequent with climate change, can negatively affect flowering, even if plants deploy physiological resistance strategies.
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Descamps C, Quinet M, Jacquemart AL. Climate Change-Induced Stress Reduce Quantity and Alter Composition of Nectar and Pollen From a Bee-Pollinated Species ( Borago officinalis, Boraginaceae). FRONTIERS IN PLANT SCIENCE 2021; 12:755843. [PMID: 34707633 PMCID: PMC8542702 DOI: 10.3389/fpls.2021.755843] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 09/20/2021] [Indexed: 05/14/2023]
Abstract
In temperate ecosystems, elevated temperatures, and drought occur especially during spring and summer, which are crucial periods for flowering, pollination, and reproduction of a majority of temperate plants. While many mechanisms may underlie pollinator decline in the wake of climate change, the interactive effects of temperature and water stress on the quantity and quality of floral nectar and pollen resources remain poorly studied. We investigated the impact of temperature rise (+3 and +6°C) and water stress (soil humidity lower than 15%) on the floral resources produced by the bee-pollinated species Borago officinalis. Nectar volume decreased with both temperature rise and water stress (6.1 ± 0.5 μl per flower under control conditions, 0.8 ± 0.1 μl per flower under high temperature and water stress conditions), resulting in a 60% decrease in the total quantity of nectar sugars (mg) produced per flower. Temperature rise but not water stress also induced a 50% decrease in pollen weight per flower but a 65% increase in pollen polypeptide concentration. Both temperature rise and water stress increased the total amino acid concentration and the essential amino acid percentage in nectar but not in pollen. In both pollen and nectar, the relative percentage of the different amino acids were modified under stresses. We discuss these modifications in floral resources in regards to plant-pollinator interactions and consequences on plant pollination success and on insect nutritional needs.
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OneHealth implications of infectious diseases of wild and managed bees. J Invertebr Pathol 2020; 186:107506. [PMID: 33249062 DOI: 10.1016/j.jip.2020.107506] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 10/27/2020] [Accepted: 11/20/2020] [Indexed: 01/23/2023]
Abstract
The OneHealth approach aims to further our understanding of the drivers of human, animal and environmental health, and, ultimately, to improve them by combining approaches and knowledge from medicine, biology and fields beyond. Wild and managed bees are essential pollinators of crops and wild flowers. Their health thus directly impacts on human and environmental health. At the same time, these bee species represent highly amenable and relevant model organisms for a OneHealth approach that aims to study fundamental epidemiological questions. In this review, we focus on how infectious diseases of wild and managed bees can be used as a OneHealth model system, informing fundamental questions on ecological immunology and disease transmission, while addressing how this knowledge can be used to tackle the issues facing pollinator health.
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Contribution of Extensive Farming Practices to the Supply of Floral Resources for Pollinators. INSECTS 2020; 11:insects11110818. [PMID: 33233506 PMCID: PMC7699504 DOI: 10.3390/insects11110818] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 11/13/2020] [Accepted: 11/17/2020] [Indexed: 11/17/2022]
Abstract
Simple Summary One of the causes of pollinator decline is the decreased availability of flower resources, that constitute their nutritional requirements. In particular, the intensification of agricultural practices has led to a loss of flower resources. For many years, as part of the Common Agricultural Policy and the efforts to preserve biodiversity, several Agri-Environmental Schemes (AESs) and extensive farming practices have been promoted in Europe. To assess the relative contribution of extensive farming practices such as hedgerows, organic crops and extensive grasslands, we compared pairs of agricultural landscapes in Belgium. We recorded the densities of the insect-pollinated plant species per biotope and per month, the abundance and diversity of the main visiting insects. In April, hedgerows and forest edges constituted the main nectar resources. In May, most of the nectar resources were produced by grasslands and mass-flowering crops. In June, extensive grasslands and organic crops contributed to nectar resources, contrarily to intensive agricultural elements. Extensive and diverse agricultural practices should therefore be encouraged to provide less fluctuating nectar resources on a landscape scale. Abstract Intensification of agricultural practices leads to a loss of floral resources and drives pollinator decline. Extensive agricultural practices are encouraged in Europe and contribute to the preservation of biodiversity. We compared three agricultural landscapes without extensive farming practices with three adjacent landscapes containing organic crops and extensively managed grasslands in Belgium. Nectar resource availability and plant–pollinator interactions were monitored from April to June. Flower density per plant species and plant–pollinator interactions were recorded in different landscape elements. In April, the main nectar resources were provided by linear elements such as hedgerows and forest edges. Nectar production peaked in May, driven by intensive grasslands and mass-flowering crops. Occurrence of extensive grasslands and organic crops significantly alleviated the nectar resource gap observed in June. Our results underscore the importance of maintaining landscape heterogeneity for continuous flower resources and highlight the specific role of extensive grasslands and organic crops in June.
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Global warming and plant-pollinator mismatches. Emerg Top Life Sci 2020; 4:77-86. [PMID: 32558904 PMCID: PMC7326340 DOI: 10.1042/etls20190139] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 03/05/2020] [Accepted: 03/16/2020] [Indexed: 12/13/2022]
Abstract
The mutualism between plants and their pollinators provides globally important ecosystem services, but it is likely to be disrupted by global warming that can cause mismatches between both halves of this interaction. In this review, we summarise the available evidence on (i) spatial or (ii) phenological shifts of one or both of the actors of this mutualism. While the occurrence of future spatial mismatches is predominantly theoretical and based on predictive models, there is growing empirical evidence of phenological mismatches occurring at the present day. Mismatches may also occur when pollinators and their host plants are still found together. These mismatches can arise due to (iii) morphological modifications and (iv) disruptions to host attraction and foraging behaviours, and it is expected that these mismatches will lead to novel community assemblages. Overall plant-pollinator interactions seem to be resilient biological networks, particularly because generalist species can buffer these changes due to their plastic behaviour. However, we currently lack information on where and why spatial mismatches do occur and how they impact the fitness of plants and pollinators, in order to fully assess if adaptive evolutionary changes can keep pace with global warming predictions.
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Parasite defense mechanisms in bees: behavior, immunity, antimicrobials, and symbionts. Emerg Top Life Sci 2020; 4:59-76. [PMID: 32558901 DOI: 10.1042/etls20190069] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 11/14/2019] [Accepted: 11/26/2019] [Indexed: 12/11/2022]
Abstract
Parasites are linked to the decline of some bee populations; thus, understanding defense mechanisms has important implications for bee health. Recent advances have improved our understanding of factors mediating bee health ranging from molecular to landscape scales, but often as disparate literatures. Here, we bring together these fields and summarize our current understanding of bee defense mechanisms including immunity, immunization, and transgenerational immune priming in social and solitary species. Additionally, the characterization of microbial diversity and function in some bee taxa has shed light on the importance of microbes for bee health, but we lack information that links microbial communities to parasite infection in most bee species. Studies are beginning to identify how bee defense mechanisms are affected by stressors such as poor-quality diets and pesticides, but further research on this topic is needed. We discuss how integrating research on host traits, microbial partners, and nutrition, as well as improving our knowledge base on wild and semi-social bees, will help inform future research, conservation efforts, and management.
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Aguirre LA, Davis JK, Stevenson PC, Adler LS. Herbivory and Time Since Flowering Shape Floral Rewards and Pollinator-Pathogen Interactions. J Chem Ecol 2020; 46:978-986. [PMID: 32876829 DOI: 10.1007/s10886-020-01213-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 08/07/2020] [Accepted: 08/24/2020] [Indexed: 10/23/2022]
Abstract
Herbivory can induce chemical changes throughout plant tissues including flowers, which could affect pollinator-pathogen interactions. Pollen is highly defended compared to nectar, but no study has examined whether herbivory affects pollen chemistry. We assessed the effects of leaf herbivory on nectar and pollen alkaloids in Nicotiana tabacum, and how herbivory-induced changes in nectar and pollen affect pollinator-pathogen interactions. We damaged leaves of Nicotiana tabacum using the specialist herbivore Manduca sexta and compared nicotine and anabasine concentrations in nectar and pollen. We then pooled nectar and pollen by collection periods (within and after one month of flowering), fed them in separate experiments to bumble bees (Bombus impatiens) infected with the gut pathogen Crithidia bombi, and assessed infections after seven days. We did not detect alkaloids in nectar, and leaf damage did not alter the effect of nectar on Crithidia counts. In pollen, herbivory induced higher concentrations of anabasine but not nicotine, and alkaloid concentrations rose and then fell as a function of days since flowering. Bees fed pollen from damaged plants had Crithidia counts 15 times higher than bees fed pollen from undamaged plants, but only when pollen was collected after one month of flowering, indicating that both damage and time since flowering affected interaction outcomes. Within undamaged treatments, bees fed late-collected pollen had Crithidia counts 10 times lower than bees fed early-collected pollen, also indicating the importance of time since flowering. Our results emphasize the role of herbivores in shaping pollen chemistry, with consequences for interactions between pollinators and their pathogens.
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Affiliation(s)
- Luis A Aguirre
- Department of Biology, University of Massachusetts, Amherst, MA, 01003, USA.
- Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA, 01003, USA.
| | - Julie K Davis
- Department of Entomology, Cornell University, Ithaca, NY, 14850, USA
| | - Philip C Stevenson
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Surrey, TW9 3AB, UK
- Natural Resources Institute, University of Greenwich, Chatham, Kent, ME4 4TB, UK
| | - Lynn S Adler
- Department of Biology, University of Massachusetts, Amherst, MA, 01003, USA
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Adler LS, Barber NA, Biller OM, Irwin RE. Flowering plant composition shapes pathogen infection intensity and reproduction in bumble bee colonies. Proc Natl Acad Sci U S A 2020; 117:11559-11565. [PMID: 32393622 PMCID: PMC7261119 DOI: 10.1073/pnas.2000074117] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Pathogens pose significant threats to pollinator health and food security. Pollinators can transmit diseases during foraging, but the consequences of plant species composition for infection is unknown. In agroecosystems, flowering strips or hedgerows are often used to augment pollinator habitat. We used canola as a focal crop in tents and manipulated flowering strip composition using plant species we had previously shown to result in higher or lower bee infection in short-term trials. We also manipulated initial colony infection to assess impacts on foraging behavior. Flowering strips using high-infection plant species nearly doubled bumble bee colony infection intensity compared to low-infection plant species, with intermediate infection in canola-only tents. Both infection treatment and flowering strips reduced visits to canola, but we saw no evidence that infection treatment shifted foraging preferences. Although high-infection flowering strips increased colony infection intensity, colony reproduction was improved with any flowering strips compared to canola alone. Effects of flowering strips on colony reproduction were explained by nectar availability, but effects of flowering strips on infection intensity were not. Thus, flowering strips benefited colony reproduction by adding floral resources, but certain plant species also come with a risk of increased pathogen infection intensity.
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Affiliation(s)
- Lynn S Adler
- Department of Biology, University of Massachusetts, Amherst, MA 01003;
| | - Nicholas A Barber
- Ecology Program Area, Department of Biology, San Diego State University, San Diego, CA 92182
| | - Olivia M Biller
- Department of Occupational Therapy, Thomas Jefferson University, Philadelphia, PA 19107
| | - Rebecca E Irwin
- Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695
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The Effect of Foraging on Bumble Bees, Bombus terrestris, Reared under Laboratory Conditions. INSECTS 2020; 11:insects11050321. [PMID: 32456127 PMCID: PMC7290516 DOI: 10.3390/insects11050321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 04/06/2020] [Accepted: 05/21/2020] [Indexed: 11/16/2022]
Abstract
Bumble bees are important pollinators broadly used by farmers in greenhouses and under conditions in which honeybee pollination is limited. As such, bumble bees are increasingly being reared for commercial purposes, which brings into question whether individuals reared under laboratory conditions are fully capable of physiological adaptation to field conditions. To understand the changes in bumble bee organism caused by foraging, we compared the fundamental physiological and immunological parameters of Bombus terrestris workers reared under constant optimal laboratory conditions with workers from sister colonies that were allowed to forage for two weeks in the field. Nutritional status and immune response were further determined in wild foragers of B.terrestris that lived under the constant influence of natural stressors. Both wild and laboratory-reared workers subjected to the field conditions had a lower protein concentration in the hemolymph and increased antimicrobial activity, the detection of which was limited in the non-foragers. However, in most of the tested parameters, specifically the level of carbohydrates, antioxidants, total hemocyte concentration in the hemolymph and melanization response, we did not observe any significant differences between bumble bee workers produced in the laboratory and wild animals, nor between foragers and non-foragers. Our results show that bumble bees reared under laboratory conditions can mount a sufficient immune response to potential pathogens and cope with differential food availability in the field, similarly to the wild bumble bee workers.
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