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Eldridge DS, Khalil A, Moulton JK, Russo L. Do local and landscape context affect the attractiveness of flower gardens to bees? PLoS One 2024; 19:e0309000. [PMID: 39231092 PMCID: PMC11373812 DOI: 10.1371/journal.pone.0309000] [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: 03/08/2024] [Accepted: 08/02/2024] [Indexed: 09/06/2024] Open
Abstract
Planting floral resources is a common strategy for increasing the abundance and diversity of beneficial flower-visiting insects in human-modified systems. However, the context of the local area and surrounding landscape may affect the attractiveness of these floral resource provisioning plots. We compared the relative effects of local floral resources and surrounding urban land-use on the abundance of bees on flowering plants in common gardens in eastern Tennessee, USA. We planted four types of common garden plots at each of five different landscapes representing a variety of surrounding land use: 1) Urban Garden, 2) Forage Grassland, 3) Mixed Agriculture, 4) Forest, and 5) Organic Farm. Each common garden plot type had a fixed plant community representing one of three plant families (Asteraceae, Fabaceae, Lamiaceae) or a mix of all three, and all four common gardens were replicated at all the sites. We concurrently sampled bees in the garden plots and in a 50 m radius (local area) around the garden plots. We found that the size of the floral display (i.e. the visual display size of flowers) and diversity of flowers in the local area did not affect bee abundance or species richness in the garden plots. Although there was a significant positive association between developed land use in a 2 km radius and bee abundance in the gardens, the effect was small, and there was no relationship between land use and bee abundance or species richness in the local area. There were significant differences in the composition of the bee community between the local area and garden plots, but the largest determinants of bee community composition and species richness in the gardens were floral display size and variation in the garden plant species in bloom. This finding is promising for anyone wishing to promote pollinator populations by providing more floral resources.
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Affiliation(s)
- Devon S Eldridge
- Department of Ecology & Evolutionary Biology, University of Tennessee, Knoxville, TN, United States of America
| | - Amani Khalil
- Department of Ecology & Evolutionary Biology, University of Tennessee, Knoxville, TN, United States of America
| | - John K Moulton
- Department of Entomology & Plant Pathology, University of Tennessee, Knoxville, TN, United States of America
| | - Laura Russo
- Department of Ecology & Evolutionary Biology, University of Tennessee, Knoxville, TN, United States of America
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2
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Delphia CM, Burkle LA, Botti-Anderson JM, O’Neill KM. Seasonality and alternative floral resources affect reproductive success of the alfalfa leafcutting bee, Megachile rotundata. PeerJ 2024; 12:e17902. [PMID: 39161964 PMCID: PMC11332388 DOI: 10.7717/peerj.17902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Accepted: 07/22/2024] [Indexed: 08/21/2024] Open
Abstract
Background Managed populations of the alfalfa leafcutting bee (ALCB), Megachile rotundata (F.), are often not sustainable. In addition to numerous mortality factors that contribute to this, the dense bee populations used to maximize alfalfa pollination quickly deplete floral resources available to bees later in the summer. Providing alternative floral resources as alfalfa declines may help to improve ALCB reproduction. Methods We examined the relationship between floral resource availability and ALCB reproduction and offspring condition via (1) a field study using alfalfa plots with and without late-blooming wildflower strips to supply food beyond alfalfa bloom, and (2) a field-cage study in which we provided bees with alfalfa, wildflowers, or both as food resources. Results In the field study, bee cell production closely followed alfalfa floral density with an initial peak followed by large declines prior to wildflower bloom. Few bees visited wildflower strips, whose presence or absence was not associated with any measure of bee reproduction. However, we found that female offspring from cells provisioned earlier in the season, when alfalfa predominated as a source of provisions, eclosed with greater body sizes and proportion body lipids relative to total body mass. For bees restricted to cages, the proportion of offspring that survived to adults was highest on pure alfalfa diets. Adding wildflowers to cages with alfalfa did not affect adult offspring production or female offspring body size and lipid content. Furthermore, although similar numbers of adults were produced on wildflowers alone as with alfalfa alone, females eclosed with smaller body sizes and lower proportion body lipids on wildflowers despite the higher protein content we estimated for wildflower pollen. We found no evidence that adding the late-season wildflower species that we chose to plant enhanced ALCB offspring numbers. Our results highlight the importance of considering multiple measures of reproductive success, including offspring body size and lipid stores, when designing and evaluating floral resource management strategies for agroecosystems.
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Affiliation(s)
- Casey M. Delphia
- Montana Entomology Collection, Montana State University, Bozeman, Montana, United States
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, Montana, United States
| | - Laura A. Burkle
- Ecology Department, Montana State University, Bozeman, Montana, United States
| | - Joshua M. Botti-Anderson
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, Montana, United States
- Fenner School of Environment and Society, Australian National University, Acton, Australian Capital Territory, Australia
| | - Kevin M. O’Neill
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, Montana, United States
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3
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Hamon LE, Kilpatrick LD, Billeisen TL. The Impact of Wildflower Habitat on Insect Functional Group Abundance in Turfgrass Systems. INSECTS 2024; 15:520. [PMID: 39057253 PMCID: PMC11277235 DOI: 10.3390/insects15070520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2024] [Revised: 06/26/2024] [Accepted: 07/09/2024] [Indexed: 07/28/2024]
Abstract
Urbanization is rapidly influencing the abundance and diversity of arthropods. Within urban systems, managed turfgrass is a prominent land cover which can support only a limited number of arthropod groups. To allow for more arthropod biodiversity and to support beneficial insects within turfgrass, increasing numbers of land managers are choosing to partially convert turf habitat to wildflower habitat using commercially available seed mixes. However, the population dynamics of arthropod groups in these systems are poorly known, with consequentially little information on best long-term practices for managing wildflower habitats in turfgrass systems. To address this gap, we sampled insects using pan traps in turfgrass systems pre- and post-implementation of wildflower habitats and examined the change in abundance of several insect families and functional guilds. Insect groups had variable responses to wildflower habitat implementation, with some groups such as sweat bees and skipper butterflies showing a decline two years post-implementation. Other groups, such as predatory flies, were relatively more abundant one and two years post-implementation. These variable responses point to the need for more research on the long-term effects of wildflower habitats on beneficial insects in turfgrass habitats.
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Affiliation(s)
- Laura E. Hamon
- Department of Entomology & Plant Pathology, North Carolina State University, Raleigh, NC 27695, USA;
| | - Lauren D. Kilpatrick
- Department of Horticulture, North Carolina State University, Raleigh, NC 27695, USA;
| | - Terri L. Billeisen
- Department of Entomology & Plant Pathology, North Carolina State University, Raleigh, NC 27695, USA;
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4
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Knauer A, Naef C, Albrecht M. Pesticide hazard, floral resource availability and natural enemies interactively drive the fitness of bee species depending on their crop fidelity. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 922:171058. [PMID: 38378056 DOI: 10.1016/j.scitotenv.2024.171058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 12/20/2023] [Accepted: 02/15/2024] [Indexed: 02/22/2024]
Affiliation(s)
- Anina Knauer
- Agroecology and Environment, Agroscope, Zürich, Switzerland.
| | - Carmen Naef
- Agroecology and Environment, Agroscope, Zürich, Switzerland
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5
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Kohl PL, Rutschmann B, Sikora LG, Wimmer N, Zahner V, D'Alvise P, Hasselmann M, Steffan-Dewenter I. Parasites, depredators, and limited resources as potential drivers of winter mortality of feral honeybee colonies in German forests. Oecologia 2023:10.1007/s00442-023-05399-6. [PMID: 37365409 PMCID: PMC10386939 DOI: 10.1007/s00442-023-05399-6] [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: 02/28/2023] [Accepted: 06/02/2023] [Indexed: 06/28/2023]
Abstract
Wild honeybees (Apis mellifera) are considered extinct in most parts of Europe. The likely causes of their decline include increased parasite burden, lack of high-quality nesting sites and associated depredation pressure, and food scarcity. In Germany, feral honeybees still colonize managed forests, but their survival rate is too low to maintain viable populations. Based on colony observations collected during a monitoring study, data on parasite prevalence, experiments on nest depredation, and analyses of land cover maps, we explored whether parasite pressure, depredation or expected landscape-level food availability explain feral colony winter mortality. Considering the colony-level occurrence of 18 microparasites in the previous summer, colonies that died did not have a higher parasite burden than colonies that survived. Camera traps installed at cavity trees revealed that four woodpecker species, great tits, and pine martens act as nest depredators. In a depredator exclusion experiment, the winter survival rate of colonies in cavities with protected entrances was 50% higher than that of colonies with unmanipulated entrances. Landscapes surrounding surviving colonies contained on average 6.4 percentage points more cropland than landscapes surrounding dying colonies, with cropland being known to disproportionately provide forage for bees in our study system. We conclude that the lack of spacious but well-protected nesting cavities and the shortage of food are currently more important than parasites in limiting populations of wild-living honeybees in German forests. Increasing the density and diversity of large tree cavities and promoting bee forage plants in forests will probably promote wild-living honeybees despite parasite pressure.
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Affiliation(s)
- Patrick L Kohl
- Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, Würzburg, Germany.
| | - Benjamin Rutschmann
- Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, Würzburg, Germany.
| | | | - Norbert Wimmer
- Bayerische Landesanstalt Für Wald Und Forstwirtschaft, Freising, Germany
| | - Volker Zahner
- Forest Ecology and Management, University of Applied Sciences Weihenstephan-Triesdorf, Freising, Germany
| | - Paul D'Alvise
- Department of Livestock Population Genomics, Institute of Animal Science, University of Hohenheim, Stuttgart, Germany
- Institute for Medical Microbiology and Hygiene, University Hospital Tübingen, Tübingen, Germany
| | - Martin Hasselmann
- Department of Livestock Population Genomics, Institute of Animal Science, University of Hohenheim, Stuttgart, Germany
| | - Ingolf Steffan-Dewenter
- Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, Würzburg, Germany
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6
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Marcacci G, Grass I, Rao VS, Kumar S S, Tharini KB, Belavadi VV, Nölke N, Tscharntke T, Westphal C. Functional diversity of farmland bees across rural-urban landscapes in a tropical megacity. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2022; 32:e2699. [PMID: 35751512 DOI: 10.1002/eap.2699] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 04/18/2022] [Accepted: 05/13/2022] [Indexed: 06/15/2023]
Abstract
Urbanization poses a major threat to biodiversity and food security, as expanding cities, especially in the Global South, increasingly compete with natural and agricultural lands. However, the impact of urban expansion on agricultural biodiversity in tropical regions is overlooked. Here we assess how urbanization affects the functional response of farmland bees, the most important pollinators for crop production. We sampled bees across three seasons in 36 conventional vegetable-producing farms spread along an urbanization gradient in Bengaluru, an Indian megacity. We investigated how landscape and local environmental drivers affected different functional traits (sociality, nesting behavior, body size, and specialization) and functional diversity (functional dispersion) of bee communities. We found that the functional responses to urbanization were trait specific with more positive than negative effects of gray area (sealed surfaces and buildings) on species richness, functional diversity, and abundance of most functional groups. As expected, larger, solitary, cavity-nesting, and, surprisingly, specialist bees benefited from urbanization. In contrast to temperate cities, the abundance of ground nesters increased in urban areas, presumably because larger patches of bare soil were still available beside roads and buildings. However, overall bee abundance and the abundance of social bees (85% of all bees) decreased with urbanization, threatening crop pollination. Crop diversity promotes taxonomic and functional diversity of bee communities. Locally, flower resources promote the abundance of all functional groups, and natural vegetation can maintain diverse pollinator communities throughout the year, especially during the noncropping season. However, exotic plants decrease functional diversity and bee specialization. To safeguard bees and their pollination services in urban farms, we recommend (1) preserving seminatural vegetation (hedges) around cropping fields to provide nesting opportunities for aboveground nesters, (2) promoting farm-level crop diversification of beneficial crops (e.g., pulses, vegetables, and spices), (3) maintaining native natural vegetation along field margins, and (4) controlling and removing invasive exotic plants that disrupt native plant-pollinator interactions. Overall, our results suggest that urban agriculture can maintain functionally diverse bee communities and, if managed in a sustainable manner, be used to develop win-win solutions for biodiversity conservation of pollinators and food security in and around cities.
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Affiliation(s)
- Gabriel Marcacci
- Functional Agrobiodiversity, Department of Crop Sciences, University of Göttingen, Göttingen, Germany
| | - Ingo Grass
- Ecology of Tropical Agricultural Systems, University of Hohenheim, Stuttgart, Germany
| | - Vikas S Rao
- Agricultural Entomology, University of Agricultural Sciences, Bangalore, India
| | - Shabarish Kumar S
- Department of Apiculture, University of Agricultural Sciences, Bangalore, India
| | - K B Tharini
- Agricultural Entomology, University of Agricultural Sciences, Bangalore, India
| | - Vasuki V Belavadi
- Agricultural Entomology, University of Agricultural Sciences, Bangalore, India
| | - Nils Nölke
- Forest Inventory and Remote Sensing, Faculty of Forest Sciences and Forest Ecology, University of Göttingen, Göttingen, Germany
| | - Teja Tscharntke
- Agroecology, Department of Crop Sciences, University of Göttingen, Göttingen, Germany
- Centre of Biodiversity and Sustainable Land Use (CBL), University of Göttingen, Göttingen, Germany
| | - Catrin Westphal
- Functional Agrobiodiversity, Department of Crop Sciences, University of Göttingen, Göttingen, Germany
- Centre of Biodiversity and Sustainable Land Use (CBL), University of Göttingen, Göttingen, Germany
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7
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Castiglioni S, Stefano M, Astolfi P, Pisani M, Carloni P. Characterisation of Bee Pollen from the Marche Region (Italy) According to the Botanical and Geographical Origin with Analysis of Antioxidant Activity and Colour, Using a Chemometric Approach. Molecules 2022; 27:7996. [PMID: 36432097 PMCID: PMC9692707 DOI: 10.3390/molecules27227996] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/11/2022] [Accepted: 11/15/2022] [Indexed: 11/19/2022] Open
Abstract
Attempts have often been made to isolate and characterise monofloral pollens to correlate nutritional with botanical properties. Nevertheless, pollen harvested in a particular area that can have a high biodiversity could have healthier properties. In addition, the analysis of the pollen's botanical composition can be important for characterising the typical flora of a specific geographical area. On this basis, various pollens collected in different locations of the Marche region (Italy) and in different harvesting periods were analyzed for botanical composition and antioxidant (total phenolic content, ABTS, DPPH and ORAC tests), granulometry and colour (CIE L*a*b*) properties to evaluate the biodiversity of pollen sources within a particular geographical area and to correlate this to the nutraceutical characteristics. Antioxidant activity results showed values generally higher than those of monofloral pollens harvested in the same areas but manually separated according to colour, shape and size. This suggests that even the floral species present in low percentages may have an influence on the nutraceutical properties of these products. The multivariate statistical elaboration of the obtained results permitted the separation of samples containing a prevalent botanical species and the grouping of all the samples into separate clusters corresponding to different areas of Marche.
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Affiliation(s)
- Sara Castiglioni
- Department of Agricultural, Food and Environmental Sciences—D3A, Università Politecnica delle Marche, Via Brecce Bianche, I-60131 Ancona, Italy
| | - Mariassunta Stefano
- Amap Marche Agricoltura Pesca—Agenzia per l’Innovazione nel Settore Agroalimentare e della Pesca, Centro Agrochimico Regionale, I-60035 Jesi, Italy
| | - Paola Astolfi
- Department of Materials, Environmental Sciences and Urban Planning—SIMAU, Università Politecnica delle Marche, Via Brecce Bianche, I-60131 Ancona, Italy
| | - Michela Pisani
- Department of Materials, Environmental Sciences and Urban Planning—SIMAU, Università Politecnica delle Marche, Via Brecce Bianche, I-60131 Ancona, Italy
| | - Patricia Carloni
- Department of Agricultural, Food and Environmental Sciences—D3A, Università Politecnica delle Marche, Via Brecce Bianche, I-60131 Ancona, Italy
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8
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Gardein H, Fabian Y, Westphal C, Tscharntke T, Hass A. Ground-nesting bees prefer bare ground areas on calcareous grasslands. Glob Ecol Conserv 2022. [DOI: 10.1016/j.gecco.2022.e02289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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9
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Knauer AC, Alaux C, Allan MJ, Dean RR, Dievart V, Glauser G, Kiljanek T, Michez D, Schwarz JM, Tamburini G, Wintermantel D, Klein AM, Albrecht M. Nutritional stress exacerbates impact of a novel insecticide on solitary bees' behaviour, reproduction and survival. Proc Biol Sci 2022; 289:20221013. [PMID: 36476004 PMCID: PMC9554715 DOI: 10.1098/rspb.2022.1013] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Pesticide exposure and food stress are major threats to bees, but their potential synergistic impacts under field-realistic conditions remain poorly understood and are not considered in current pesticide risk assessments. We conducted a semi-field experiment to examine the single and interactive effects of the novel insecticide flupyradifurone (FPF) and nutritional stress on fitness proxies in the solitary bee Osmia bicornis. Individually marked bees were released into flight cages with monocultures of buckwheat, wild mustard or purple tansy, which were assigned to an insecticide treatment (FPF or control) in a crossed design. Nutritional stress, which was high in bees foraging on buckwheat, intermediate on wild mustard and low on purple tansy, modulated the impact of insecticide exposure. Within the first day after application of FPF, mortality of bees feeding on buckwheat was 29 times higher compared with control treatments, while mortality of FPF exposed and control bees was similar in the other two plant species. Moreover, we found negative synergistic impacts of FPF and nutritional stress on offspring production, flight activity, flight duration and flower visitation frequency. These results reveal that environmental policies and risk assessment schemes that ignore interactions among anthropogenic stressors will fail to adequately protect bees and the pollination services they provide.
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Affiliation(s)
| | - Cedric Alaux
- UR406 Abeilles and Environnement, Site Agroparc, INRAE, Avignon, France
| | | | | | - Virginie Dievart
- UR406 Abeilles and Environnement, Site Agroparc, INRAE, Avignon, France
| | - Gaétan Glauser
- Neuchâtel Platform of Analytical Chemistry, University of Neuchâtel, Neuchâtel, Switzerland
| | - Tomasz Kiljanek
- Department of Pharmacology and Toxicology, National Veterinary Research Institute, Pulawy, Poland
| | - Denis Michez
- Institute for Biosciences, University of Mons, Mons, Belgium
| | | | - Giovanni Tamburini
- Department of Soil, Plant and Food Sciences (DiSSPA—Entomology), University of Bari, Bari, Italy
| | - Dimitry Wintermantel
- Nature Conservation and Landscape Ecology, University of Freiburg, Freiburg, Germany
| | - Alexandra-Maria Klein
- Nature Conservation and Landscape Ecology, University of Freiburg, Freiburg, Germany
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10
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Neumüller U, Burger H, Mayr AV, Hopfenmüller S, Krausch S, Herwig N, Burger R, Diestelhorst O, Emmerich K, Haider M, Kiefer M, Konicek J, Kornmilch JC, Moser M, Saure C, Schanowski A, Scheuchl E, Sing J, Wagner M, Witter J, Schwenninger HR, Ayasse M. Artificial Nesting Hills Promote Wild Bees in Agricultural Landscapes. INSECTS 2022; 13:726. [PMID: 36005351 PMCID: PMC9409424 DOI: 10.3390/insects13080726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/09/2022] [Accepted: 08/11/2022] [Indexed: 06/15/2023]
Abstract
The availability of nesting resources influences the persistence and survival of bee communities. Although a positive effect of artificial nesting structures has frequently been shown for aboveground cavity-nesting wild bees, studies on below ground-nesting bees are rare. Artificial nesting hills designed to provide nesting habitats for ground-nesting bees were therefore established within the BienABest project in 20 regions across Germany. Wild bee communities were monitored for two consecutive years, accompanied by recordings of landscape and abiotic nest site variables. Bee activity and species richness increased from the first to the second year after establishment; this was particularly pronounced in landscapes with a low cover of semi-natural habitat. The nesting hills were successively colonized, indicating that they should exist for many years, thereby promoting a species-rich bee community. We recommend the construction of nesting hills on sun-exposed sites with a high thermal gain of the substrate because the bees prefer south-facing sites with high soil temperatures. Although the soil composition of the nesting hills plays a minor role, we suggest using local soil to match the needs of the local bee community. We conclude that artificial nesting structures for ground-nesting bees act as a valuable nesting resource for various bee species, particularly in highly degraded landscapes. We offer a construction and maintenance guide for the successful establishment of nesting hills for bee conservation.
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Affiliation(s)
- Ulrich Neumüller
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, 89081 Ulm, Germany
| | - Hannah Burger
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, 89081 Ulm, Germany
| | - Antonia V. Mayr
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, 89081 Ulm, Germany
| | - Sebastian Hopfenmüller
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, 89081 Ulm, Germany
| | - Sabrina Krausch
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, 89081 Ulm, Germany
| | - Nadine Herwig
- Institute for Ecological Chemistry, Plant Analysis and Stored Product Protection, Julius Kühn-Institute, 14195 Berlin, Germany
| | - Ronald Burger
- Independent Researcher, IFAUN-Faunistik und Funktionale Artenvielfalt, 67246 Dirmstein, Germany
| | | | | | - Mare Haider
- Independent Researcher, Institut für Landschaftsökologie und Naturschutz Bühl, 77815 Bühl, Germany
| | - Manuel Kiefer
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, 89081 Ulm, Germany
| | - Jonas Konicek
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, 89081 Ulm, Germany
| | | | - Marina Moser
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, 89081 Ulm, Germany
| | - Christoph Saure
- Independent Researcher, Büro für Tierökologische Studien, 12167 Berlin, Germany
| | - Arno Schanowski
- Independent Researcher, Institut für Landschaftsökologie und Naturschutz Bühl, 77815 Bühl, Germany
| | | | - Julia Sing
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, 89081 Ulm, Germany
| | - Max Wagner
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, 89081 Ulm, Germany
| | - Julia Witter
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, 89081 Ulm, Germany
| | - Hans R. Schwenninger
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, 89081 Ulm, Germany
- Independent Researcher, Kompetenzzentrum Wildbienen gGmbH, 67433 Neustadt an der Weinstraße, Germany
| | - Manfred Ayasse
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, 89081 Ulm, Germany
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11
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Straub L, Strobl V, Bruckner S, Camenzind DW, Van Oystaeyen A, Wäckers F, Williams GR, Neumann P. Buffered fitness components: Antagonism between malnutrition and an insecticide in bumble bees. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 833:155098. [PMID: 35398139 DOI: 10.1016/j.scitotenv.2022.155098] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/30/2022] [Accepted: 04/03/2022] [Indexed: 06/14/2023]
Abstract
Global insect biodiversity declines due to reduced fitness are linked to interactions between environmental stressors. In social insects, inclusive fitness depends on successful mating of reproductives, i.e. males and queens, and efficient collaborative brood care by workers. Therefore, interactive effects between malnutrition and environmental pollution on sperm and feeding glands (hypopharyngeal glands (HPGs)) would provide mechanisms for population declines, unless buffered against due to their fitness relevance. However, while negative effects for bumble bee colony fitness are known, the effects of malnutrition and insecticide exposure singly and in combination on individuals are poorly understood. Here we show, in a fully-crossed laboratory experiment, that malnutrition and insecticide exposure result in neutral or antagonistic interactions for spermatozoa and HPGs of bumble bees, Bombus terrestris, suggesting strong selection to buffer key colony fitness components. No significant effects were observed for mortality and consumption, but significant negative effects were revealed for spermatozoa traits and HPGs. The combined effects on these parameters were not higher than the individual stressor effects, which indicates an antagonistic interaction between both. Despite the clear potential for additive effects, due to the individual stressors impairing muscle quality and neurological control, simultaneous malnutrition and insecticide exposure surprisingly did not reveal an increased impact compared to individual stressors, probably due to key fitness traits being resilient. Our data support that stressor interactions require empirical tests on a case-by-case basis and need to be regarded in context to understand underlying mechanisms and so adequately mitigate the ongoing decline of the entomofauna.
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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.
| | - Verena Strobl
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Selina Bruckner
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, USA
| | - Domenic W Camenzind
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | | | | | - Geoffrey R Williams
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, USA
| | - Peter Neumann
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland; Agroscope, Swiss Bee Research Centre, Bern, Switzerland
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12
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Straub L, Strobl V, Yañez O, Albrecht M, Brown MJ, Neumann P. Do pesticide and pathogen interactions drive wild bee declines? Int J Parasitol Parasites Wildl 2022; 18:232-243. [PMID: 35800107 PMCID: PMC9253050 DOI: 10.1016/j.ijppaw.2022.06.001] [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: 12/22/2021] [Revised: 06/03/2022] [Accepted: 06/05/2022] [Indexed: 11/20/2022]
Abstract
There is clear evidence for wild insect declines globally. Habitat loss, climate change, pests, pathogens and environmental pollution have all been shown to cause detrimental effects on insects. However, interactive effects between these stressors may be the key to understanding reported declines. Here, we review the literature on pesticide and pathogen interactions for wild bees, identify knowledge gaps, and suggest avenues for future research fostering mitigation of the observed declines. The limited studies available suggest that effects of pesticides most likely override effects of pathogens. Bees feeding on flowers and building sheltered nests, are likely less adapted to toxins compared to other insects, which potential susceptibility is enhanced by the reduced number of genes encoding detoxifying enzymes compared with other insect species. However, to date all 10 studies using a fully-crossed design have been conducted in the laboratory on social bees using Crithidia spp. or Nosema spp., identifying an urgent need to test solitary bees and other pathogens. Similarly, since laboratory studies do not necessarily reflect field conditions, semi-field and field studies are essential if we are to understand these interactions and their potential effects in the real-world. In conclusion, there is a clear need for empirical (semi-)field studies on a range of pesticides, pathogens, and insect species to better understand the pathways and mechanisms underlying their potential interactions, in particular their relevance for insect fitness and population dynamics. Such data are indispensable to drive forward robust modelling of interactive effects in different environmental settings and foster predictive science. This will enable pesticide and pathogen interactions to be put into the context of other stressors more broadly, evaluating their relative importance in driving the observed declines of wild bees and other insects. Ultimately, this will enable the development of more effective mitigation measures to protect bees and the ecosystem services they supply.
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Affiliation(s)
- Lars Straub
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Verena Strobl
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Orlando Yañez
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | | | - Mark J.F. Brown
- Department of Biological Sciences, Royal Holloway University of London, Egham, UK
| | - Peter Neumann
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Swiss Bee Research Centre, Agroscope, Bern, Switzerland
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Balfour NJ, Ratnieks FLW. The disproportionate value of ‘weeds’ to pollinators and biodiversity. J Appl Ecol 2022. [DOI: 10.1111/1365-2664.14132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Nicholas J. Balfour
- Laboratory of Apiculture & Social Insects, School of Life Sciences University of Sussex Brighton UK
| | - Francis L. W. Ratnieks
- Laboratory of Apiculture & Social Insects, School of Life Sciences University of Sussex Brighton UK
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14
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Reeg J, Strigl L, Jeltsch F. Agricultural buffer zone thresholds to safeguard functional bee diversity: Insights from a community modeling approach. Ecol Evol 2022; 12:e8748. [PMID: 35342570 PMCID: PMC8933324 DOI: 10.1002/ece3.8748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 02/18/2022] [Accepted: 03/03/2022] [Indexed: 11/10/2022] Open
Abstract
Wild bee species are important pollinators in agricultural landscapes. However, population decline was reported over the last decades and is still ongoing. While agricultural intensification is a major driver of the rapid loss of pollinating species, transition zones between arable fields and forest or grassland patches, i.e., agricultural buffer zones, are frequently mentioned as suitable mitigation measures to support wild bee populations and other pollinator species. Despite the reported general positive effect, it remains unclear which amount of buffer zones is needed to ensure a sustainable and permanent impact for enhancing bee diversity and abundance. To address this question at a pollinator community level, we implemented a process-based, spatially explicit simulation model of functional bee diversity dynamics in an agricultural landscape. More specifically, we introduced a variable amount of agricultural buffer zones (ABZs) at the transition of arable to grassland, or arable to forest patches to analyze the impact on bee functional diversity and functional richness. We focused our study on solitary bees in a typical agricultural area in the Northeast of Germany. Our results showed positive effects with at least 25% of virtually implemented agricultural buffer zones. However, higher amounts of ABZs of at least 75% should be considered to ensure a sufficient increase in Shannon diversity and decrease in quasi-extinction risks. These high amounts of ABZs represent effective conservation measures to safeguard the stability of pollination services provided by solitary bee species. As the model structure can be easily adapted to other mobile species in agricultural landscapes, our community approach offers the chance to compare the effectiveness of conservation measures also for other pollinator communities in future.
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Affiliation(s)
- Jette Reeg
- Department of Ecology/MacroecologyInstitute of Biochemistry and BiologyUniversity of PotsdamPotsdamGermany
- Berlin‐Brandenburg Institute of Advanced Biodiversity ResearchBerlinGermany
| | - Lea Strigl
- Berlin‐Brandenburg Institute of Advanced Biodiversity ResearchBerlinGermany
- Department of Plant Ecology and Nature ConservationInstitute of Biochemistry and BiologyUniversity of PotsdamPotsdamGermany
| | - Florian Jeltsch
- Berlin‐Brandenburg Institute of Advanced Biodiversity ResearchBerlinGermany
- Department of Plant Ecology and Nature ConservationInstitute of Biochemistry and BiologyUniversity of PotsdamPotsdamGermany
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15
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Knauer AC, Gallmann J, Albrecht M. Bee Tracker-an open-source machine learning-based video analysis software for the assessment of nesting and foraging performance of cavity-nesting solitary bees. Ecol Evol 2022; 12:e8575. [PMID: 35342575 PMCID: PMC8928898 DOI: 10.1002/ece3.8575] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/21/2021] [Accepted: 12/30/2021] [Indexed: 11/10/2022] Open
Abstract
The foraging and nesting performance of bees can provide important information on bee health and is of interest for risk and impact assessment of environmental stressors. While radiofrequency identification (RFID) technology is an efficient tool increasingly used for the collection of behavioral data in social bee species such as honeybees, behavioral studies on solitary bees still largely depend on direct observations, which is very time-consuming. Here, we present a novel automated methodological approach of individually and simultaneously tracking and analyzing foraging and nesting behavior of numerous cavity-nesting solitary bees. The approach consists of monitoring nesting units by video recording and automated analysis of videos by machine learning-based software. This Bee Tracker software consists of four trained deep learning networks to detect bees that enter or leave their nest and to recognize individual IDs on the bees' thorax and the IDs of their nests according to their positions in the nesting unit. The software is able to identify each nest of each individual nesting bee, which permits to measure individual-based measures of reproductive success. Moreover, the software quantifies the number of cavities a female enters until it finds its nest as a proxy of nest recognition, and it provides information on the number and duration of foraging trips. By training the software on 8 videos recording 24 nesting females per video, the software achieved a precision of 96% correct measurements of these parameters. The software could be adapted to various experimental setups by training it according to a set of videos. The presented method allows to efficiently collect large amounts of data on cavity-nesting solitary bee species and represents a promising new tool for the monitoring and assessment of behavior and reproductive success under laboratory, semi-field, and field conditions.
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Carvell C, Mitschunas N, McDonald R, Hulmes S, Hulmes L, O'Connor RS, Garratt MP, Potts SG, Fountain MT, Sadykova D, Edwards M, Nowakowski M, Pywell RF, Redhead JW. Establishment and management of wildflower areas for insect pollinators in commercial orchards. Basic Appl Ecol 2022; 58:2-14. [PMID: 35115899 PMCID: PMC8752464 DOI: 10.1016/j.baae.2021.11.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 11/07/2021] [Indexed: 11/17/2022]
Abstract
Sown wildflower areas are increasingly recommended as an agri-environmental intervention measure, but evidence for their success is limited to particular insect groups or hampered by the challenges of establishing seed mixes and maintaining flower abundance over time. We conducted a replicated experiment to establish wildflower areas to support insect pollinators in apple orchards. Over three years, and across 23 commercial UK orchards with and without sown wildflowers, we conducted 828 transect surveys across various non-crop habitats. We found that the abundance of flower-visiting solitary bees, bumblebees, honeybees, and beetles was increased in sown wildflower areas, compared with existing non-crop habitats in control orchards, from the second year following floral establishment. Abundance of hoverflies and other non-syrphid flies was increased in wildflower areas from the first year. Beyond the effect of wildflower areas, solitary bee abundance was also positively related to levels of floral cover in other local habitats within orchards, but neither local nor wider landscape-scale context affected abundance of other studied insect taxa within study orchards. There was a change in plant community composition on the sown wildflower areas between years, and in patterns of flowering within and between years, showing a succession from unsown weedy species towards a dominance of sown species over time. We discuss how the successful establishment of sown wildflower areas and delivery of benefits for different insect taxa relies on appropriate and reactive management practices as a key component of any such agri-environment scheme.
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Schuberta LF, Hellwigb N, Kirmera A, Schmid-Eggerc C, Schmidta A, Diekerb P, Tischewa S. Habitat quality and surrounding landscape structures influence wild bee occurrence in perennial wildflower strips. Basic Appl Ecol 2021. [DOI: 10.1016/j.baae.2021.12.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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18
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Hoffmann H, Peter F, Donath TW, Diekötter T. Landscape- and time-dependent benefits of wildflower areas to ground-dwelling arthropods. Basic Appl Ecol 2021. [DOI: 10.1016/j.baae.2021.12.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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19
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Time since establishment drives bee and hoverfly diversity, abundance of crop-pollinating bees and aphidophagous hoverflies in perennial wildflower strips. Basic Appl Ecol 2021. [DOI: 10.1016/j.baae.2021.10.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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