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Zaharieva A, Rusanov K, Rusanova M, Paunov M, Yordanova Z, Mantovska D, Tsacheva I, Petrova D, Mishev K, Dobrev PI, Lacek J, Filepová R, Zehirov G, Vassileva V, Mišić D, Motyka V, Chaneva G, Zhiponova M. Uncovering the Interrelation between Metabolite Profiles and Bioactivity of In Vitro- and Wild-Grown Catmint ( Nepeta nuda L.). Metabolites 2023; 13:1099. [PMID: 37887424 PMCID: PMC10609352 DOI: 10.3390/metabo13101099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/14/2023] [Accepted: 10/18/2023] [Indexed: 10/28/2023] Open
Abstract
Nepeta nuda L. is a medicinal plant enriched with secondary metabolites serving to attract pollinators and deter herbivores. Phenolics and iridoids of N. nuda have been extensively investigated because of their beneficial impacts on human health. This study explores the chemical profiles of in vitro shoots and wild-grown N. nuda plants (flowers and leaves) through metabolomic analysis utilizing gas chromatography and mass spectrometry (GC-MS). Initially, we examined the differences in the volatiles' composition in in vitro-cultivated shoots comparing them with flowers and leaves from plants growing in natural environment. The characteristic iridoid 4a-α,7-β,7a-α-nepetalactone was highly represented in shoots of in vitro plants and in flowers of plants from nature populations, whereas most of the monoterpenes were abundant in leaves of wild-grown plants. The known in vitro biological activities encompassing antioxidant, antiviral, antibacterial potentials alongside the newly assessed anti-inflammatory effects exhibited consistent associations with the total content of phenolics, reducing sugars, and the identified metabolic profiles in polar (organic acids, amino acids, alcohols, sugars, phenolics) and non-polar (fatty acids, alkanes, sterols) fractions. Phytohormonal levels were also quantified to infer the regulatory pathways governing phytochemical production. The overall dataset highlighted compounds with the potential to contribute to N. nuda bioactivity.
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Affiliation(s)
- Anna Zaharieva
- Department of Plant Physiology, Faculty of Biology, Sofia University “St. Kliment Ohridski”, 1164 Sofia, Bulgaria; (A.Z.); (Z.Y.); (D.M.); (D.P.); (G.C.)
| | - Krasimir Rusanov
- Department of Agrobiotechnology, Agrobioinstitute, Agricultural Academy, 1164 Sofia, Bulgaria; (K.R.)
| | - Mila Rusanova
- Department of Agrobiotechnology, Agrobioinstitute, Agricultural Academy, 1164 Sofia, Bulgaria; (K.R.)
| | - Momchil Paunov
- Department of Biophysics and Radiobiology, Faculty of Biology, Sofia University, 1164 Sofia, Bulgaria;
| | - Zhenya Yordanova
- Department of Plant Physiology, Faculty of Biology, Sofia University “St. Kliment Ohridski”, 1164 Sofia, Bulgaria; (A.Z.); (Z.Y.); (D.M.); (D.P.); (G.C.)
| | - Desislava Mantovska
- Department of Plant Physiology, Faculty of Biology, Sofia University “St. Kliment Ohridski”, 1164 Sofia, Bulgaria; (A.Z.); (Z.Y.); (D.M.); (D.P.); (G.C.)
| | - Ivanka Tsacheva
- Department of Biochemistry, Faculty of Biology, Sofia University, 1164 Sofia, Bulgaria;
| | - Detelina Petrova
- Department of Plant Physiology, Faculty of Biology, Sofia University “St. Kliment Ohridski”, 1164 Sofia, Bulgaria; (A.Z.); (Z.Y.); (D.M.); (D.P.); (G.C.)
| | - Kiril Mishev
- Department of Molecular Biology and Genetics, Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (K.M.); (G.Z.); (V.V.)
| | - Petre I. Dobrev
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany of the Czech Academy of Sciences, 165 02 Praha, Czech Republic; (P.I.D.); (J.L.); (R.F.); (V.M.)
| | - Jozef Lacek
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany of the Czech Academy of Sciences, 165 02 Praha, Czech Republic; (P.I.D.); (J.L.); (R.F.); (V.M.)
| | - Roberta Filepová
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany of the Czech Academy of Sciences, 165 02 Praha, Czech Republic; (P.I.D.); (J.L.); (R.F.); (V.M.)
| | - Grigor Zehirov
- Department of Molecular Biology and Genetics, Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (K.M.); (G.Z.); (V.V.)
| | - Valya Vassileva
- Department of Molecular Biology and Genetics, Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (K.M.); (G.Z.); (V.V.)
| | - Danijela Mišić
- Department of Plant Physiology, Institute for Biological Research “Siniša Stanković”, National Institute of the Republic of Serbia, University of Belgrade, 11060 Belgrade, Serbia;
| | - Václav Motyka
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany of the Czech Academy of Sciences, 165 02 Praha, Czech Republic; (P.I.D.); (J.L.); (R.F.); (V.M.)
| | - Ganka Chaneva
- Department of Plant Physiology, Faculty of Biology, Sofia University “St. Kliment Ohridski”, 1164 Sofia, Bulgaria; (A.Z.); (Z.Y.); (D.M.); (D.P.); (G.C.)
| | - Miroslava Zhiponova
- Department of Plant Physiology, Faculty of Biology, Sofia University “St. Kliment Ohridski”, 1164 Sofia, Bulgaria; (A.Z.); (Z.Y.); (D.M.); (D.P.); (G.C.)
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Jones PL, Martin KR, Prachand SV, Hastings AP, Duplais C, Agrawal AA. Compound-Specific Behavioral and Enzymatic Resistance to Toxic Milkweed Cardenolides in a Generalist Bumblebee Pollinator. J Chem Ecol 2023; 49:418-427. [PMID: 36745328 DOI: 10.1007/s10886-023-01408-3] [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: 12/28/2022] [Revised: 01/26/2023] [Accepted: 01/27/2023] [Indexed: 02/07/2023]
Abstract
Plant secondary metabolites that defend leaves from herbivores also occur in floral nectar. While specialist herbivores often have adaptations providing resistance to these compounds in leaves, many social insect pollinators are generalists, and therefore are not expected to be as resistant to such compounds. The milkweeds, Asclepias spp., contain toxic cardenolides in all tissues including floral nectar. We compared the concentrations and identities of cardenolides between tissues of the North American common milkweed Asclepias syriaca, and then studied the effect of the predominant cardenolide in nectar, glycosylated aspecioside, on an abundant pollinator. We show that a generalist bumblebee, Bombus impatiens, a common pollinator in eastern North America, consumes less nectar with experimental addition of ouabain (a standard cardenolide derived from Apocynacid plants native to east Africa) but not with addition of glycosylated aspecioside from milkweeds. At a concentration matching that of the maximum in the natural range, both cardenolides reduced activity levels of bees after four days of consumption, demonstrating toxicity despite variation in behavioral deterrence (i.e., consumption). In vitro enzymatic assays of Na+/K+-ATPase, the target site of cardenolides, showed lower toxicity of the milkweed cardenolide than ouabain for B. impatiens, indicating that the lower deterrence may be due to greater tolerance to glycosylated aspecioside. In contrast, there was no difference between the two cardenolides in toxicity to the Na+/K+-ATPase from a control insect, the fruit fly Drosophila melanogaster. Accordingly, this work reveals that even generalist pollinators such as B. impatiens may have adaptations to reduce the toxicity of specific plant secondary metabolites that occur in nectar, despite visiting flowers from a wide variety of plants over the colony's lifespan.
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Affiliation(s)
| | - Kyle R Martin
- Department of Biology, Bowdoin College, Brunswick, ME, USA
| | | | - Amy P Hastings
- Department of Ecology & Evolutionary Biology, Cornell University, Ithaca, NY, USA
| | - Christophe Duplais
- Department of Entomology, Cornell AgriTech, Cornell University, Geneva, NY, USA
| | - Anurag A Agrawal
- Department of Ecology & Evolutionary Biology, Cornell University, Ithaca, NY, USA
- Department of Entomology, Cornell AgriTech, Cornell University, Geneva, NY, USA
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3
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Dahake A, Raguso RA, Goyret J. Context and the functional use of information in insect sensory ecology. CURRENT OPINION IN INSECT SCIENCE 2023; 58:101058. [PMID: 37217002 DOI: 10.1016/j.cois.2023.101058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 03/26/2023] [Accepted: 05/18/2023] [Indexed: 05/24/2023]
Abstract
Context-specific behaviors emerge from the interaction between an animal's internal state and its external environment. Although the importance of context is acknowledged in the field of insect sensory ecology, there is a lack of synthesis on this topic stemming from challenges in conceptualizing 'context'. We address this challenge by gleaning over the recent findings on the sensory ecology of mosquitoes and other insect pollinators. We discuss internal states and their temporal dynamics, from those lasting minutes to hours (host-seeking) to those lasting days to weeks (diapause, migration). Of the many patterns reviewed, at least three were common to all taxa studied. First, different sensory cues gain prominence depending on the insect's internal state. Second, similar sensory circuits between related species can result in different behavioral outcomes. And third, ambient conditions can dramatically alter internal states and behaviors.
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Affiliation(s)
- Ajinkya Dahake
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, USA
| | - Robert A Raguso
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, USA
| | - Joaquin Goyret
- Department of Biological Sciences, University of Tennessee Martin, Martin, TN, USA.
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Ivers NA, Jha S. Biogeography, climate, and land use create a mosaic of parasite risk in native bumble bees. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 868:161545. [PMID: 36649773 DOI: 10.1016/j.scitotenv.2023.161545] [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: 11/11/2022] [Revised: 01/06/2023] [Accepted: 01/07/2023] [Indexed: 06/17/2023]
Abstract
Host-parasite interactions are crucial to the regulation of host population growth, as they often impact both long-term population stability and ecological functioning. Animal hosts navigate a number of environmental conditions, including local climate, anthropogenic land use, and varying degrees of spatial isolation, all of which can mediate parasitism exposure. Despite this, we know little about the potential for these environmental conditions to impact pathogen prevalence at biogeographic scales, especially for key ecosystem service-providing animals. Bees are essential pollination providers that may be particularly sensitive to biogeography, climate, and land-use as these factors are known to limit bee dispersal and contribute to underlying population genetic variation, which may also impact host-parasite interactions. Importantly, many native bumble bee species have recently shown geographic range contractions, reduced genetic diversity, and increased parasitism rates, highlighting the potential importance of interacting and synergistic stressors. In this study, we incorporate spatially explicit environmental, biogeographic, and land-use data in combination with genetically derived host population data to conduct a large-scale epidemiological assessment of the drivers of pathogen prevalence across >1000 km for a keystone western US pollinator, the bumble bee Bombus vosnesenskii. We found high rates of infection from Crithidia bombi and C. expoekii, which show strong spatial autocorrelation and which were more prevalent in northern latitudes. We also show that land use barriers best explained differences in parasite prevalence and parasite community composition, while precipitation, elevation, and B. vosnesenskii nesting density were important drivers of parasite prevalence. Overall, our results demonstrate that human land use can impact critical host-parasite interactions for native bees at massive spatial scales. Further, our work indicates that disease-related survey and conservation measures should take into account the independent and interacting influences of climate, biogeography, land use, and local population dynamics.
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Affiliation(s)
- Nicholas A Ivers
- University of Texas at Austin, Dept. Integrative Biology, United States of America.
| | - Shalene Jha
- University of Texas at Austin, Dept. Integrative Biology, United States of America
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5
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Jones P, Agrawal AA. Caffeine and ethanol in nectar interact with flower color impacting bumblebee behavior. Behav Ecol Sociobiol 2022. [DOI: 10.1007/s00265-022-03208-3] [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]
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6
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Kleindorfer S, Colombelli‐Négrel D, Common LK, O’Connor JA, Peters KJ, Katsis AC, Dudaniec RY, Sulloway FJ, Adreani NM. Functional traits and foraging behaviour: avian vampire fly larvae change the beak and fitness of their Darwin’s finch hosts. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14061] [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)
- Sonia Kleindorfer
- College of Science and Engineering Flinders University Adelaide Australia
- Konrad Lorenz Research Center for Behavior and Cognition and Department of Behavioral and Cognitive Biology University of Vienna Vienna Austria
| | | | - Lauren K. Common
- College of Science and Engineering Flinders University Adelaide Australia
| | | | - Katharina J. Peters
- College of Science and Engineering Flinders University Adelaide Australia
- Evolutionary Genetics Group, Department of Anthropology University of Zurich Zurich Switzerland
- School of Earth and Environment Christchurch New Zealand
| | - Andrew C. Katsis
- College of Science and Engineering Flinders University Adelaide Australia
| | | | | | - Nicolas M. Adreani
- Konrad Lorenz Research Center for Behavior and Cognition and Department of Behavioral and Cognitive Biology University of Vienna Vienna Austria
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7
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Fitch G, Figueroa LL, Koch H, Stevenson PC, Adler LS. Understanding effects of floral products on bee parasites: Mechanisms, synergism, and ecological complexity. Int J Parasitol Parasites Wildl 2022; 17:244-256. [PMID: 35299588 PMCID: PMC8920997 DOI: 10.1016/j.ijppaw.2022.02.011] [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: 12/21/2021] [Revised: 02/24/2022] [Accepted: 02/25/2022] [Indexed: 12/27/2022]
Abstract
Floral nectar and pollen commonly contain diverse secondary metabolites. While these compounds are classically thought to play a role in plant defense, recent research indicates that they may also reduce disease in pollinators. Given that parasites have been implicated in ongoing bee declines, this discovery has spurred interest in the potential for 'medicinal' floral products to aid in pollinator conservation efforts. We review the evidence for antiparasitic effects of floral products on bee diseases, emphasizing the importance of investigating the mechanism underlying antiparasitic effects, including direct or host-mediated effects. We discuss the high specificity of antiparasitic effects of even very similar compounds, and highlight the need to consider how nonadditive effects of multiple compounds, and the post-ingestion transformation of metabolites, mediate the disease-reducing capacity of floral products. While the bulk of research on antiparasitic effects of floral products on bee parasites has been conducted in the lab, we review evidence for the impact of such effects in the field, and highlight areas for future research at the floral product-bee disease interface. Such research has great potential both to enhance our understanding of the role of parasites in shaping plant-bee interactions, and the role of plants in determining bee-parasite dynamics. This understanding may in turn reveal new avenues for pollinator conservation.
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Affiliation(s)
- Gordon Fitch
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Laura L. Figueroa
- Department of Entomology, Cornell University, Ithaca, NY, 14853, USA
- Department of Environmental Conservation, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Hauke Koch
- Royal Botanic Gardens, Kew Green, Kew, Richmond, Surrey, TW9 3AE, UK
| | - Philip C. Stevenson
- Royal Botanic Gardens, Kew Green, Kew, Richmond, Surrey, TW9 3AE, UK
- Natural Resources Institute, University of Greenwich, Kent, ME4 4TB, UK
| | - Lynn S. Adler
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, 01003, USA
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Palmer-Young EC, Schwarz RS, Chen Y, Evans JD. Punch in the gut: Parasite tolerance of phytochemicals reflects host diet. Environ Microbiol 2022; 24:1805-1817. [PMID: 35315572 DOI: 10.1111/1462-2920.15981] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 03/18/2022] [Accepted: 03/20/2022] [Indexed: 11/30/2022]
Abstract
Gut parasites of plant-eating insects are exposed to antimicrobial phytochemicals that can reduce infection. Trypanosomatid gut parasites infect insects of diverse nutritional ecologies as well as mammals and plants, raising the question of how host diet-associated phytochemicals shape parasite evolution and host specificity. To test the hypothesis that phytochemical tolerance of trypanosomatids reflects the chemical ecology of their hosts, we compared related parasites from honey bees and mosquitoes-hosts that differ in phytochemical consumption-and contrasted our results with previous studies on phylogenetically related, human-parasitic Leishmania. We identified one bacterial and ten plant-derived substances with known antileishmanial activity that also inhibited honey bee parasites associated with colony collapse. Bee parasites exhibited greater tolerance of chrysin-a flavonoid found in nectar, pollen, and plant resin-derived propolis. In contrast, mosquito parasites were more tolerant of cinnamic acid-a product of lignin decomposition present in woody debris-rich larval habitats. Parasites from both hosts tolerated many compounds that inhibit Leishmania, hinting at possible trade-offs between phytochemical tolerance and mammalian infection. Our results implicate the phytochemistry of host diets as a potential driver of insect-trypanosomatid associations, and identify compounds that could be incorporated into colony diets or floral landscapes to ameliorate infection in bees. This article is protected by copyright. All rights reserved.
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Affiliation(s)
| | - Ryan S Schwarz
- Department of Biology, Fort Lewis College, Durango, CO, USA
| | | | - Jay D Evans
- USDA-ARS Bee Research Lab, Beltsville, MD, USA
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Richman SK, Maalouf IM, Smilanich AM, Marquez Sanchez D, Miller SZ, Leonard AS. A neonicotinoid pesticide alters how nectar chemistry affects bees. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | | | - Sharron Z. Miller
- Department of Biology University of Nevada Reno NV 89557 USA
- Department of Entomology Michigan State University Lansing MI 48864 USA
| | - Anne S. Leonard
- Department of Biology University of Nevada Reno NV 89557 USA
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Bartlett LJ, Martinez-Mejia C, Delaplane KS. Honey Bees (Apis mellifera Hymenoptera: Apidae) Preferentially Avoid Sugar Solutions Supplemented with Field-Relevant Concentrations of Hydrogen Peroxide Despite High Tolerance Limits. JOURNAL OF INSECT SCIENCE (ONLINE) 2022; 22:6484925. [PMID: 34958663 PMCID: PMC8711758 DOI: 10.1093/jisesa/ieab102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Indexed: 06/14/2023]
Abstract
Honey bees (Apis mellifera L. Hymeoptera: Apidae) use hydrogen peroxide (synthesized by excreted glucose oxidase) as an important component of social immunity. However, both tolerance of hydrogen peroxide and the production of glucose oxidase in honey is costly. Hydrogen peroxide may also be encountered by honey bees at high concentrations in nectar while foraging, however despite its presence both in their foraged and stored foods, it is unclear if and how bees monitor concentrations of, and their behavioral responses to, hydrogen peroxide. The costs of glucose oxidase production and the presence of hydrogen peroxide in both nectar and honey suggest hypotheses that honey bees preferentially forage on hydrogen peroxide supplemented feed syrups at certain concentrations, and avoid feed syrups supplemented with hydrogen peroxide at concentrations above some tolerance threshold. We test these hypotheses and find that, counter to expectation, honey bees avoid glucose solutions supplemented with field-relevant hydrogen peroxide concentrations and either avoid or don't differentiate supplemented sucrose solutions when given choice assays. This is despite honey bees showing high tolerance for hydrogen peroxide in feed solutions, with no elevated mortality until concentrations of hydrogen peroxide exceed 1% (v/v) in solution, with survival apparent even at concentrations up to 10%. The behavioral interaction of honey bees with hydrogen peroxide during both within-colony synthesis in honey and when foraging on nectar therefore likely relies on interactions with other indicator molecules, and maybe constrained evolutionarily in its plasticity, representing a constitutive immune mechanism.
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Affiliation(s)
- Lewis J Bartlett
- Center for the Ecology of Infectious Diseases, Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
| | | | - Keith S Delaplane
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
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Seasonal Variation in Host Plant Chemistry Drives Sequestration in a Specialist Caterpillar. J Chem Ecol 2021; 48:79-88. [PMID: 34738204 DOI: 10.1007/s10886-021-01321-7] [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: 08/06/2021] [Revised: 09/30/2021] [Accepted: 10/10/2021] [Indexed: 10/19/2022]
Abstract
Sequestration of plant secondary metabolites by herbivores can vary across both host plant phenology and herbivore ontogeny, but few studies have explored how they concurrently change in the field. We explored variation in iridoid glycoside concentration and composition in white turtlehead, Chelone glabra, as well as sequestration of iridoid glycosides by its specialist herbivore, the Baltimore checkerspot, Euphydryas phaeton, across the development of both herbivore and host plant. In 2012 we sampled plants to describe seasonal variation in the concentrations of two iridoid glycosides, aucubin and catalpol. In 2017, we sampled both host plants and caterpillars over an entire growing season and explored the relationship between plant chemistry and herbivore sequestration. We also compared iridoid glycoside concentrations of plants with and without herbivory to gain insight into whether levels of secondary compounds were impacted by herbivory. We found that total plant iridoid glycosides varied across the season and that total sequestered iridoid glycosides in caterpillars closely mirrored concentration patterns in plants. However, the magnitude of sequestration by caterpillars ranged from 2 to 20 times the concentrations in host plants, with different proportions of aucubin and catalpol. In addition, plants with herbivory had lower iridoid glycoside concentrations than plants without herbivory, although this difference changed over time. These results suggest that while variation in host plant secondary metabolites may be a dominant factor driving sequestration, other ecological factors may mitigate the relationship between host plant chemistry and herbivore sequestration.
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Carvalheiro LG, Bartomeus I, Rollin O, Timóteo S, Tinoco CF. The role of soils on pollination and seed dispersal. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200171. [PMID: 34365822 PMCID: PMC8349634 DOI: 10.1098/rstb.2020.0171] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2020] [Indexed: 12/21/2022] Open
Abstract
Ongoing environmental changes are affecting physical, chemical and biological soil components. Evidence of impacts of soil changes on pollinators' and seed dispersers' behaviour, fitness and density is scarce, but growing. Here, we reviewed information on such impacts and on a number of mechanisms that may explain its propagation, taking into account the full range of resources required by the large and diverse number of species of these two important functional groups. We show that while there is substantial evidence on the effects of soil nitrogen enrichment and changes in soil water content on the quality and quantity of floral and fruit resources, little is known on the effects of changes of other soil properties (e.g. soil pH, soil structure, other nutrients). Also, the few studies showing correlations between soil changes and pollinator and seed disperser foraging behaviour or fitness do not clearly identify the mechanisms that explain such correlation. Finally, most studies (including those with nitrogen and water) are local and limited to a small number of species, and it remains unclear how variable such effects are across time and geographical regions, and the strength of interactive effects between soil properties. Increasing research on this topic, taking into consideration how impacts propagate through species interaction networks, will provide essential information to predict impacts of ongoing environmental changes and help guide conservation plans that aim to minimize impacts on ecosystem functioning. This article is part of the theme issue 'The role of soils in delivering Nature's Contributions to People'.
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Affiliation(s)
- Luísa G. Carvalheiro
- Departamento de Ecologia, Universidade Federal de Goiás, 74001-970 Goiânia, Brasil
- Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | | | - Orianne Rollin
- Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Sérgio Timóteo
- Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal
| | - Carla Faleiro Tinoco
- Departamento de Ecologia, Universidade Federal de Goiás, 74001-970 Goiânia, Brasil
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Measuring foraging preferences in bumble bees: a comparison of popular laboratory methods and a test for sucrose preferences following neonicotinoid exposure. Oecologia 2021; 196:963-976. [PMID: 34250559 DOI: 10.1007/s00442-021-04979-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 06/23/2021] [Indexed: 10/20/2022]
Abstract
Animals develop food preferences based on taste, nutritional quality and to avoid environmental toxins. Yet, measuring preferences in an experimental setting can be challenging since ecologically realistic assays can be time consuming, while simplified assays may not capture natural sampling behavior. Field realism is a particular challenge when studying behavioral responses to environmental toxins in lab-based assays, given that toxins can themselves impact sampling behavior, masking our ability to detect preferences. We address these challenges by comparing different experimental methods for measuring sucrose concentration preference in bumble bees (Bombus impatiens), evaluating the utility of two preference chamber-based methods (ad libitum versus a novel restricted-sampling assay) in replicating bees' preferences when they fly freely between artificial flowers in a foraging arena. We find that the restricted-sampling method matched a free-flying scenario more closely than the ad libitum protocol, and we advocate for expanded use of this approach, given its ease of implementation. We then performed a second experiment using the new protocol to ask whether consuming the neonicotinoid pesticide imidacloprid, known to suppress feeding motivation, interfered with the expression of sucrose preferences. After consuming imidacloprid, bees were less likely to choose the higher-quality sucrose even as they gained experience with both options. Thus, we provide evidence that pesticides interfere with bees' ability to discriminate between floral rewards that differ in value. This work highlights a simple protocol for assessing realistic foraging preferences in bees and provides an efficient way for researchers to measure the impacts of anthropogenic factors on preference expression.
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Adler LS, Irwin RE, McArt SH, Vannette RL. Floral traits affecting the transmission of beneficial and pathogenic pollinator-associated microbes. CURRENT OPINION IN INSECT SCIENCE 2021; 44:1-7. [PMID: 32866657 PMCID: PMC7914268 DOI: 10.1016/j.cois.2020.08.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/17/2020] [Accepted: 08/19/2020] [Indexed: 05/22/2023]
Abstract
Flowers provide resources for pollinators, and can also be transmission venues for beneficial or pathogenic pollinator-associated microbes. Floral traits could mediate transmission similarly for beneficial and pathogenic microbes, although some beneficial microbes can grow in flowers while pathogenic microbes may only survive until acquired by a new host. In spite of conceptual similarities, research on beneficial and pathogenic pollinator-associated microbes has progressed mostly independently. Recent advances demonstrate that floral traits are associated with transmission of beneficial and pathogenic microbes, with consequences for pollinator populations and communities. However, there is a near-absence of experimental manipulations of floral traits to determine causal effects on transmission, and a need to understand how floral, microbe and host traits interact to mediate transmission.
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Affiliation(s)
- Lynn S Adler
- Department of Biology, University of Massachusetts, 221 Morrill Science Center, 611 N. Pleasant St., Amherst MA 01002 USA.
| | - Rebecca E Irwin
- Department of Applied Ecology, North Carolina State University, 127 David Clark Labs, 100 Eugene Brooks Ave., Raleigh, NC 27695 USA
| | - Scott H McArt
- Department of Entomology, Cornell University, 4132 Comstock Hall, 129 Garden Ave., Ithaca, NY 14853 USA
| | - Rachel L Vannette
- Department of Entomology and Nematology, University of California, 43 Briggs Hall, Davis CA 95616 USA
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15
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Schmitt A, Roy R, Carter CJ. Nectar antimicrobial compounds and their potential effects on pollinators. CURRENT OPINION IN INSECT SCIENCE 2021; 44:55-63. [PMID: 33771735 DOI: 10.1016/j.cois.2021.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 02/24/2021] [Accepted: 03/15/2021] [Indexed: 06/12/2023]
Abstract
Nectar is a sugary, aqueous solution that plants offer as a reward to animal mutualists for visitation. Since nectars are so nutrient-rich, they often harbor significant microbial communities, which can be pathogenic, benign, or even sometimes beneficial to plant fitness. Through recent advances, it is now clear that these microbes alter nectar chemistry, which in turn influences mutualist behavior (e.g. pollinator visitation). To counteract unwanted microbial growth, nectars often contain antimicrobial compounds, especially in the form of proteins, specialized (secondary) metabolites, and metals. This review covers our current understanding of nectar antimicrobials, as well as their interplay with both microbes and insect visitors.
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Affiliation(s)
- Anthony Schmitt
- Department of Plant & Microbial Biology, University of Minnesota, 1479 Gortner Ave, St. Paul, MN 55108, USA
| | - Rahul Roy
- Biology Department, St. Catherine University, 2004 Randolph Ave, St. Paul, MN 55105, USA
| | - Clay J Carter
- Department of Plant & Microbial Biology, University of Minnesota, 1479 Gortner Ave, St. Paul, MN 55108, USA.
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16
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Vidkjær NH, Fomsgaard IS, Kryger P. LC-MS/MS Quantification Reveals Ample Gut Uptake and Metabolization of Dietary Phytochemicals in Honey Bees ( Apis mellifera). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:627-637. [PMID: 33416324 PMCID: PMC7884015 DOI: 10.1021/acs.jafc.0c03584] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 11/15/2020] [Accepted: 11/30/2020] [Indexed: 05/13/2023]
Abstract
The honey bee pollen/nectar diet is rich in bioactive phytochemicals and recent studies have demonstrated the potential of phytochemicals to influence honey bee disease resistance. To unravel the role of dietary phytochemicals in honey bee health it is essential to understand phytochemical uptake, bioavailability, and metabolism but presently limited knowledge exists. With this study we aim to build a knowledge foundation. For 5 days, we continuously fed honey bees on eight individual phytochemicals and measured the concentrations in whole and dissected bees by HPLC-MS/MS. Ample phytochemical metabolization was observed, and only 6-30% of the consumed quantities were recovered. Clear differences in metabolization rates were evident, with atropine, aucubin, and triptolide displaying significantly slower metabolism. Phytochemical gut uptake was also demonstrated, and oral bioavailability was 4-31%, with the highest percentages observed for amygdalin, triptolide, and aucubin. We conclude that differences in the chemical properties and structure impact phytochemical uptake and metabolism.
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Affiliation(s)
- Nanna Hjort Vidkjær
- Department
of Biology and Biological Engineering, Chalmers
University of Technology, SE-412 96 Göteborg, Sweden
- Department
of Agroecology, Aarhus University, Forsøgsvej 1, DK-4200 Slagelse, Denmark
| | - Inge S. Fomsgaard
- Department
of Agroecology, Aarhus University, Forsøgsvej 1, DK-4200 Slagelse, Denmark
| | - Per Kryger
- Department
of Agroecology, Aarhus University, Forsøgsvej 1, DK-4200 Slagelse, Denmark
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17
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Pagnotta E, Montaut S, Matteo R, Rollin P, Nuzillard JM, Lazzeri L, Bagatta M. Glucosinolates in Reseda lutea L.: Distribution in plant tissues during flowering time. BIOCHEM SYST ECOL 2020. [DOI: 10.1016/j.bse.2020.104043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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18
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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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19
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Rivest S, Forrest JRK. Defence compounds in pollen: why do they occur and how do they affect the ecology and evolution of bees? THE NEW PHYTOLOGIST 2020; 225:1053-1064. [PMID: 31569278 DOI: 10.1111/nph.16230] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 09/25/2019] [Indexed: 05/23/2023]
Abstract
Pollen plays two important roles in angiosperm reproduction, serving as a vehicle for the plant's male gametes, but also, in many species, as a lure for pollen-feeding animals. Despite being an important food source for many pollinators, pollen often contains compounds with known deterrent or toxic properties, as documented in a growing number of studies. Here we review these studies and discuss the role of pollen defensive compounds in the coevolutionary relationship between plants and bees, the preeminent consumers of pollen. Next, we evaluate three hypotheses that may explain the existence of defensive compounds in pollen. The pleiotropy hypothesis, which proposes that defensive compounds in pollen merely reflect physiological spillover from other plant tissues, is contradicted by evidence from several species. Although plants may experience selection to defend pollen against poor-quality pollinators, we also find only partial support for the protection-against-pollen-collection-hypothesis. Finally, pollen defences might protect pollen from colonisation by antagonistic microorganisms (antimicrobial hypothesis), although data to evaluate this idea are scarce. Further research on the effects of pollen defensive compounds on pollinators, pollen thieves, and pollen-colonising microbes will be needed to understand why many plants have chemically defended pollen, and the consequences of those defences for pollen consumers.
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Affiliation(s)
- Sébastien Rivest
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, K1N 6N5, Canada
| | - Jessica R K Forrest
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, K1N 6N5, Canada
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20
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Alger SA, Burnham PA, Brody AK. Flowers as viral hot spots: Honey bees (Apis mellifera) unevenly deposit viruses across plant species. PLoS One 2019; 14:e0221800. [PMID: 31532764 PMCID: PMC6750573 DOI: 10.1371/journal.pone.0221800] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 08/15/2019] [Indexed: 01/19/2023] Open
Abstract
RNA viruses, once considered specific to honey bees, are suspected of spilling over from managed bees into wild pollinators; however, transmission routes are largely unknown. A widely accepted yet untested hypothesis states that flowers serve as bridges in the transmission of viruses between bees. Here, using a series of controlled experiments with captive bee colonies, we examined the role of flowers in bee virus transmission. We first examined if honey bees deposit viruses on flowers and whether bumble bees become infected after visiting contaminated flowers. We then examined whether plant species differ in their propensity to harbor viruses and if bee visitation rates increase the likelihood of virus deposition on flowers. Our experiment demonstrated, for the first time, that honey bees deposit viruses on flowers. However, the two viruses we examined, black queen cell virus (BQCV) and deformed wing virus (DWV), were not equally distributed across plant species, suggesting that differences in floral traits, virus ecology and/or foraging behavior may mediate the likelihood of deposition. Bumble bees did not become infected after visiting flowers previously visited by honey bees suggesting that transmission via flowers may be a rare occurrence and contingent on multiplicative factors and probabilities such as infectivity of virus strain across bee species, immunocompetence, virus virulence, virus load, and the probability a bumble bee will contact a virus particle on a flower. Our study is among the first to experimentally examine the role of flowers in bee virus transmission and uncovers promising avenues for future research.
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Affiliation(s)
- Samantha A. Alger
- Biology Department, University of Vermont, Burlington, Vermont, United States of America
- * E-mail:
| | - P. Alexander Burnham
- Biology Department, University of Vermont, Burlington, Vermont, United States of America
| | - Alison K. Brody
- Biology Department, University of Vermont, Burlington, Vermont, United States of America
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21
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Vanderplanck M, Roger N, Moerman R, Ghisbain G, Gérard M, Popowski D, Granica S, Fournier D, Meeus I, Piot N, Smagghe G, Terrana L, Michez D. Bumble bee parasite prevalence but not genetic diversity impacted by the invasive plant
Impatiens glandulifera. Ecosphere 2019. [DOI: 10.1002/ecs2.2804] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- Maryse Vanderplanck
- Research Institute for Biosciences Laboratory of Zoology University of Mons Place du Parc 20 Mons B‐7000 Belgium
- Evo‐Eco‐Paleo ‐ UMR 8198 CNRS Université de Lille Lille F‐59000 France
| | - Nathalie Roger
- Research Institute for Biosciences Laboratory of Zoology University of Mons Place du Parc 20 Mons B‐7000 Belgium
| | - Romain Moerman
- Research Institute for Biosciences Laboratory of Zoology University of Mons Place du Parc 20 Mons B‐7000 Belgium
- Evolutionary Biology and Ecology Université libre de Bruxelles Av. F.D. Roosevelt 50 Brussels B‐1000 Belgium
| | - Guillaume Ghisbain
- Research Institute for Biosciences Laboratory of Zoology University of Mons Place du Parc 20 Mons B‐7000 Belgium
| | - Maxence Gérard
- Research Institute for Biosciences Laboratory of Zoology University of Mons Place du Parc 20 Mons B‐7000 Belgium
| | - Dominik Popowski
- Department of Pharmacognosy and Molecular Basis of Phytotherapy Medical University of Warsaw Banacha 1 Warsaw 02‐097 Poland
| | - Sebastian Granica
- Department of Pharmacognosy and Molecular Basis of Phytotherapy Medical University of Warsaw Banacha 1 Warsaw 02‐097 Poland
| | - Denis Fournier
- Evolutionary Biology and Ecology Université libre de Bruxelles Av. F.D. Roosevelt 50 Brussels B‐1000 Belgium
| | - Ivan Meeus
- Department of Crop Protection Faculty of Bioscience Engineering Laboratory of Agrozoology Ghent University Coupure Links 653 Ghent B‐9000 Belgium
| | - Niels Piot
- Department of Crop Protection Faculty of Bioscience Engineering Laboratory of Agrozoology Ghent University Coupure Links 653 Ghent B‐9000 Belgium
| | - Guy Smagghe
- Department of Crop Protection Faculty of Bioscience Engineering Laboratory of Agrozoology Ghent University Coupure Links 653 Ghent B‐9000 Belgium
| | - Lucas Terrana
- Research Institute for Biosciences Biology of Marine Organisms and Biomimetics University of Mons Place du Parc 20 Mons B‐7000 Belgium
| | - Denis Michez
- Research Institute for Biosciences Laboratory of Zoology University of Mons Place du Parc 20 Mons B‐7000 Belgium
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22
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Identification of Potential Metabolites Mediating Bird's Selective Feeding on Prunus mira Flowers. BIOMED RESEARCH INTERNATIONAL 2019; 2019:1395480. [PMID: 31341887 PMCID: PMC6612375 DOI: 10.1155/2019/1395480] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 06/04/2019] [Indexed: 01/18/2023]
Abstract
In peach orchards, birds severely damage flowers during blossom season, decreasing the fruit yield potential. However, the wild peach species Prunus mira shows intraspecific variations of bird damage, indicating that some of the wild trees have developed strategies to avert bird foraging. Motivated by this observation, we formulated the present study to identify the potential flower metabolites mediating the bird's selective feeding behavior in P. mira flowers. The birds' preferred (FG) and avoided (BFT) flowers were collected from wild P. mira trees at three different locations, and their metabolite contents were detected, quantified, and compared. The widely-targeted metabolomics approach was employed to detect a diverse set of 603 compounds, predominantly, organic acids, amino acid derivatives, nucleotide and its derivatives, and flavones. By quantitatively comparing the metabolite contents between FG and BFT, three candidate metabolites, including Eriodictiol 6-C-hexoside 8-C-hexoside-O-hexoside, Luteolin O-hexosyl-O-hexosyl-O-hexoside, and Salvianolic acid A, were differentially accumulated and showed the same pattern across the three sampling locations. Distinctly, Salvianolic acid A was abundantly accumulated in FG but absent in BFT, implying that it may be the potential metabolite attracting birds in some P. mira flowers. Overall, this study sheds light on the diversity of the floral metabolome in P. mira and suggests that the bird's selective feeding behavior may be mediated by variations in floral metabolite contents.
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23
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Michaud KM, Irwin RE, Barber NA, Adler LS. Preinfection Effects of Nectar Secondary Compounds on a Bumble Bee Gut Pathogen. ENVIRONMENTAL ENTOMOLOGY 2019; 48:685-690. [PMID: 30855085 DOI: 10.1093/ee/nvz018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Indexed: 06/09/2023]
Abstract
Bumble bee pollinators can be exposed to pathogens when foraging on flowers previously visited by infected individuals. Infectious cells may be deposited in floral nectar, providing a site for pathogens to interact with nectar secondary compounds prior to infecting bees. Some nectar secondary compounds can reduce pathogen counts in infected bumble bees, but we know less about how exposure to these compounds directly affects pathogens prior to being ingested by their host. We exposed the trypanosomatid gut pathogen, Crithidia bombi (Lipa & Triggiani 1988) (Trypanosomatida: Trypanosomatidae), to six different compounds found in nectar (aucubin, catalpol, nicotine, thymol, anabasine, and citric acid) for 1-h prior to ingestion by Bombus impatiens (Cresson 1863) (Hymenoptera: Apidae) workers that were then reared for 1 wk on a control diet. All of these compounds except citric acid reduce pathogen levels when consumed in hosts after infection, and citric acid is a common preservative found in citrus fruits and some honeys. We found that both citric acid and aucubin reduced Crithidia cell counts compared with controls. However, catalpol, nicotine, thymol, and anabasine did not have significant effects on Crithidia levels. These results suggest that Crithidia exposure in some floral nectars may reduce cell viability, resulting in a lower risk to visiting pollinators, but this effect may not be widespread across all flowering species.
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Affiliation(s)
| | - Rebecca E Irwin
- Department of Applied Ecology, North Carolina State University, Raleigh, NC
| | - Nicholas A Barber
- Department of Biology & Ecology Program Area, San Diego State University, San Diego, CA
| | - Lynn S Adler
- Department of Biology, University of Massachusetts, Amherst, MA
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24
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Fouks B, Wagoner KM. Pollinator parasites and the evolution of floral traits. Ecol Evol 2019; 9:6722-6737. [PMID: 31236255 PMCID: PMC6580263 DOI: 10.1002/ece3.4989] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 12/16/2018] [Accepted: 01/27/2019] [Indexed: 11/26/2022] Open
Abstract
The main selective force driving floral evolution and diversity is plant-pollinator interactions. Pollinators use floral signals and indirect cues to assess flower reward, and the ensuing flower choice has major implications for plant fitness. While many pollinator behaviors have been described, the impact of parasites on pollinator foraging decisions and plant-pollinator interactions have been largely overlooked. Growing evidence of the transmission of parasites through the shared-use of flowers by pollinators demonstrate the importance of behavioral immunity (altered behaviors that enhance parasite resistance) to pollinator health. During foraging bouts, pollinators can protect themselves against parasites through self-medication, disease avoidance, and grooming. Recent studies have documented immune behaviors in foraging pollinators, as well as the impacts of such behaviors on flower visitation. Because pollinator parasites can affect flower choice and pollen dispersal, they may ultimately impact flower fitness. Here, we discuss how pollinator immune behaviors and floral traits may affect the presence and transmission of pollinator parasites, as well as how pollinator parasites, through these immune behaviors, can impact plant-pollinator interactions. We further discuss how pollinator immune behaviors can impact plant fitness, and how floral traits may adapt to optimize plant fitness in response to pollinator parasites. We propose future research directions to assess the role of pollinator parasites in plant-pollinator interactions and evolution, and we propose better integration of the role of pollinator parasites into research related to pollinator optimal foraging theory, floral diversity and agricultural practices.
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Affiliation(s)
- Bertrand Fouks
- Department of BiologyUniversity of North Carolina at GreensboroGreensboroNorth Carolina
| | - Kaira M. Wagoner
- Department of BiologyUniversity of North Carolina at GreensboroGreensboroNorth Carolina
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25
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A comparison of coffee floral traits under two different agricultural practices. Sci Rep 2019; 9:7331. [PMID: 31089179 PMCID: PMC6517588 DOI: 10.1038/s41598-019-43753-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 04/26/2019] [Indexed: 01/09/2023] Open
Abstract
Floral traits and rewards are important in mediating interactions between plants and pollinators. Agricultural management practices can affect abiotic factors known to influence floral traits; however, our understanding of the links between agricultural practices and floral trait expression is still poorly understood. Variation in floral morphological, nectar, and pollen traits of two important agricultural species, Coffea arabica and C. canephora, was assessed under different agricultural practices (sun and shade). Corolla diameter and corolla tube length were larger and pollen total nitrogen content greater in shade plantations of C. canephora than sun plantations. Corolla tube length and anther filament length were larger in shade plantations of C. arabica. No effect of agricultural practice was found on nectar volume, sugar or caffeine concentrations, or pollen production. Pollen total nitrogen content was lower in sun than shade plantations of C. canephora, but no difference was found between sun and shade for C. arabica. This study provides baseline data on the influence of agronomic practices on C. arabica and C. canephora floral traits and also helps fill a gap in knowledge about the effects of shade trees on floral traits, which can be pertinent to other agroforestry systems.
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26
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Álvarez-Pérez S, Lievens B, Fukami T. Yeast-Bacterium Interactions: The Next Frontier in Nectar Research. TRENDS IN PLANT SCIENCE 2019; 24:393-401. [PMID: 30792076 DOI: 10.1016/j.tplants.2019.01.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 01/19/2019] [Accepted: 01/25/2019] [Indexed: 05/28/2023]
Abstract
Beyond its role as a reward for pollinators, floral nectar also provides a habitat for specialized and opportunistic yeasts and bacteria. These microbes modify nectar chemistry, often altering mutualistic relationships between plants and pollinators in ways that we are only beginning to understand. Many studies on this multi-partite system have focused on either yeasts or bacteria without consideration of yeast-bacterium interactions, but recent evidence suggests that such interactions drive the assembly of nectar microbial communities and its consequences for pollination. Unexplored potential mechanisms of yeast-bacterium interactions include the formation of physical complexes, nutritional interactions, antibiosis, signaling-based interactions, and horizontal gene transfer. We argue that studying these mechanisms can elucidate how nectar microbial communities are established and affect plant fitness via pollinators.
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Affiliation(s)
- Sergio Álvarez-Pérez
- KU Leuven, Department of Microbial and Molecular Systems (M2S), Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Campus De Nayer, B-2860 Sint-Katelijne-Waver, Belgium; Department of Biology, Stanford University, Stanford, CA 94305, USA.
| | - Bart Lievens
- KU Leuven, Department of Microbial and Molecular Systems (M2S), Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Campus De Nayer, B-2860 Sint-Katelijne-Waver, Belgium
| | - Tadashi Fukami
- Department of Biology, Stanford University, Stanford, CA 94305, USA. https://twitter.com/@TadashiFukami
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27
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Parachnowitsch AL, Manson JS, Sletvold N. Evolutionary ecology of nectar. ANNALS OF BOTANY 2019; 123:247-261. [PMID: 30032269 PMCID: PMC6344224 DOI: 10.1093/aob/mcy132] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Accepted: 06/16/2018] [Indexed: 05/24/2023]
Abstract
Background Floral nectar is an important determinant of plant-pollinator interactions and an integral component of pollination syndromes, suggesting it is under pollinator-mediated selection. However, compared to floral display traits, we know little about the evolutionary ecology of nectar. Combining a literature review with a meta-analysis approach, we summarize the evidence for heritable variation in nectar traits and link this variation to pollinator response and plant fitness. We further review associations between nectar traits and floral signals and discuss them in the context of honest signalling and targets of selection. Scope Although nectar is strongly influenced by environmental factors, heritable variation in nectar production rate has been documented in several populations (mean h2 = 0.31). Almost nothing is known about heritability of other nectar traits, such as sugar and amino acid concentrations. Only a handful of studies have quantified selection on nectar traits, and few find statistically significant selection. Pollinator responses to nectar traits indicate they may drive selection, but studies tying pollinator preferences to plant fitness are lacking. So far, only one study conclusively identified pollinators as selective agents on a nectar trait, and the role of microbes, herbivores, nectar robbers and abiotic factors in nectar evolution is largely hypothetical. Finally, there is a trend for positive correlations among floral cues and nectar traits, indicating honest signalling of rewards. Conclusions Important progress can be made by studies that quantify current selection on nectar in natural populations, as well as experimental approaches that identify the target traits and selective agents involved. Signal-reward associations suggest that correlational selection may shape evolution of nectar traits, and studies exploring these more complex forms of natural selection are needed. Many questions about nectar evolution remain unanswered, making this a field ripe for future research.
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Affiliation(s)
- Amy L Parachnowitsch
- Plant Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
- Department of Biology, University of New Brunswick, Fredericton, New Brunswick, Canada
| | - Jessamyn S Manson
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Nina Sletvold
- Plant Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
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28
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Bello MO, Zaki AA, Aloko S, Fasinu PS, Bello EO, Ajao UL, Oguntoye OS. The genus Vitex: An overview of iridoids as chemotaxonomic marker. BENI-SUEF UNIVERSITY JOURNAL OF BASIC AND APPLIED SCIENCES 2018. [DOI: 10.1016/j.bjbas.2017.07.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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29
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Abstract
Declines in wild and managed bee species richness and abundances have been observed throughout Europe and North America in recent decades. These declines have led to questions regarding pollination of wild and cultivated plants. In response to these concerns, efforts towards the conservation of pollinators have been initiated. Part of this conservation effort should be to provide the basic nutritional needs for bees. Nutrition plays one of the most important roles in bee growth, development, and reproduction. There is a large body of information regarding honey bee nutrition, whereas we lack nutritional information on native wild bees. Our knowledge of bumble bee nutritional needs has increased since the introduction of commercial rearing and sale of certain bumble bee species; however, there is still a lack of basic nutritional guidelines such as minimum dietary needs of proteins, amino acids, lipids, and sterols. The large difference in physiology and life history between honey bees and North American wild bees suggests that their nutritional requirements could be quite different.
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30
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Palmer-Young EC, Farrell IW, Adler LS, Milano NJ, Egan PA, Junker RR, Irwin RE, Stevenson PC. Chemistry of floral rewards: intra- and interspecific variability of nectar and pollen secondary metabolites across taxa. ECOL MONOGR 2018. [DOI: 10.1002/ecm.1335] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Evan C. Palmer-Young
- Department of Biology; University of Massachusetts at Amherst; Amherst Massachusetts 01003 USA
| | - Iain W. Farrell
- Royal Botanic Gardens, Kew; Richmond Surrey TW9 3AB United Kingdom
| | - Lynn S. Adler
- Department of Biology; University of Massachusetts at Amherst; Amherst Massachusetts 01003 USA
| | - Nelson J. Milano
- Department of Biology; University of Massachusetts at Amherst; Amherst Massachusetts 01003 USA
| | - Paul A. Egan
- Department of Plant Protection Biology; Swedish University of Agricultural Sciences; SE-23053 Alnarp Sweden
| | - Robert R. Junker
- Department of Bioscience; University of Salzburg; Hellbrunnerstrasse 34 5020 Salzburg Austria
| | - Rebecca E. Irwin
- Department of Applied Ecology; North Carolina State University; Raleigh North Carolina 27695 USA
| | - Philip C. Stevenson
- Royal Botanic Gardens, Kew; Richmond Surrey TW9 3AB United Kingdom
- University of Greenwich; Medway ME4 4 TB United Kingdom
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Jacobsen DJ, Raguso RA. Lingering Effects of Herbivory and Plant Defenses on Pollinators. Curr Biol 2018; 28:R1164-R1169. [DOI: 10.1016/j.cub.2018.08.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Egan PA, Adler LS, Irwin RE, Farrell IW, Palmer-Young EC, Stevenson PC. Crop Domestication Alters Floral Reward Chemistry With Potential Consequences for Pollinator Health. FRONTIERS IN PLANT SCIENCE 2018; 9:1357. [PMID: 30319666 PMCID: PMC6169423 DOI: 10.3389/fpls.2018.01357] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 08/28/2018] [Indexed: 05/29/2023]
Abstract
Crop domestication can lead to weakened expression of plant defences, with repercussions for herbivore and pathogen susceptibility. However, little is known about how domestication alters traits that mediate other important ecological interactions in crops, such as pollination. Secondary metabolites, which underpin many defence responses in plants, also occur widely in nectar and pollen and influence plant-pollinator interactions. Thus, domestication may also affect secondary compounds in floral rewards, with potential consequences for pollinators. To test this hypothesis, we chemically analysed nectar and pollen from wild and cultivated plants of highbush blueberry (Vaccinium corymbosum L.), before conducting an artificial diet bioassay to examine pollinator-pathogen interactions. Our results indicated that domestication has significantly altered the chemical composition of V. corymbosum nectar and pollen, and reduced pollen chemical diversity in cultivated plants. Of 20 plant metabolites identified in floral rewards, 13 differed significantly between wild and cultivated plants, with a majority showing positive associations with wild compared to cultivated plants. These included the amino acid phenylalanine (4.5 times higher in wild nectar, 11 times higher in wild pollen), a known bee phagostimulant and essential nutrient; and the antimicrobial caffeic acid ester 4-O-caffeoylshikimic acid (two times higher in wild nectar). We assessed the possible biological relevance of variation in caffeic acid esters in bioassays, using the commercially available 3-O-caffeoylquinic acid. This compound reduced Bombus impatiens infection by a prominent gut pathogen (Crithidia) at concentrations that occurred in wild but not cultivated plants, suggesting that domestication may influence floral traits with consequences for bee health. Appreciable levels of genetic variation and heritability were found for most floral reward chemical traits, indicating good potential for selective breeding. Our study provides the first assessment of plant domestication effects on floral reward chemistry and its potential repercussions for pollinator health. Given the central importance of pollinators for agriculture, we discuss the need to extend such investigations to pollinator-dependent crops more generally and elaborate on future research directions to ascertain wider trends, consequences for pollinators, mechanisms, and breeding solutions.
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Affiliation(s)
- Paul A. Egan
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Lynn S. Adler
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, United States
| | - Rebecca E. Irwin
- Department of Applied Ecology, North Carolina State University, Raleigh, NC, United States
| | | | - Evan C. Palmer-Young
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, United States
| | - Philip C. Stevenson
- Royal Botanic Gardens, Kew, Richmond, United Kingdom
- Natural Resources Institute, University of Greenwich, London, United Kingdom
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Giacomini JJ, Leslie J, Tarpy DR, Palmer-Young EC, Irwin RE, Adler LS. Medicinal value of sunflower pollen against bee pathogens. Sci Rep 2018; 8:14394. [PMID: 30258066 PMCID: PMC6158195 DOI: 10.1038/s41598-018-32681-y] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 09/07/2018] [Indexed: 02/07/2023] Open
Abstract
Global declines in pollinators, including bees, can have major consequences for ecosystem services. Bees are dominant pollinators, making it imperative to mitigate declines. Pathogens are strongly implicated in the decline of native and honey bees. Diet affects bee immune responses, suggesting the potential for floral resources to provide natural resistance to pathogens. We discovered that sunflower (Helianthus annuus) pollen dramatically and consistently reduced a protozoan pathogen (Crithidia bombi) infection in bumble bees (Bombus impatiens) and also reduced a microsporidian pathogen (Nosema ceranae) of the European honey bee (Apis mellifera), indicating the potential for broad anti-parasitic effects. In a field survey, bumble bees from farms with more sunflower area had lower Crithidia infection rates. Given consistent effects of sunflower in reducing pathogens, planting sunflower in agroecosystems and native habitat may provide a simple solution to reduce disease and improve the health of economically and ecologically important pollinators.
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Affiliation(s)
- Jonathan J Giacomini
- North Carolina State University, Department of Applied Ecology, 100 Eugene Brooks Avenue, Raleigh, NC, 27695, USA.
| | - Jessica Leslie
- University of Massachusetts Amherst, Department of Biology, 611 North Pleasant Street, Amherst, MA, 01003, USA
| | - David R Tarpy
- North Carolina State University, Department of Entomology & Plant Pathology, Campus Box 7613, Raleigh, NC 27695, USA
| | - Evan C Palmer-Young
- University of Massachusetts Amherst, Department of Biology, 611 North Pleasant Street, Amherst, MA, 01003, USA
| | - Rebecca E Irwin
- North Carolina State University, Department of Applied Ecology, 100 Eugene Brooks Avenue, Raleigh, NC, 27695, USA
| | - Lynn S Adler
- University of Massachusetts Amherst, Department of Biology, 611 North Pleasant Street, Amherst, MA, 01003, USA
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Bernardo MA, Singer MS. Parasite-altered feeding behavior in insects: integrating functional and mechanistic research frontiers. ACTA ACUST UNITED AC 2018; 220:2848-2857. [PMID: 28814608 DOI: 10.1242/jeb.143800] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Research on parasite-altered feeding behavior in insects is contributing to an emerging literature that considers possible adaptive consequences of altered feeding behavior for the host or the parasite. Several recent ecoimmunological studies show that insects can adaptively alter their foraging behavior in response to parasitism. Another body of recent work shows that infection by parasites can change the behavior of insect hosts to benefit the parasite; manipulations of host feeding behavior may be part of this phenomenon. Here, we address both the functional and the underlying physiological frontiers of parasite-altered feeding behavior in order to spur research that better integrates the two. Functional categories of parasite-altered behavior that are adaptive for the host include prophylaxis, therapy and compensation, while host manipulation is adaptive for the parasite. To better understand and distinguish prophylaxis, therapy and compensation, further study of physiological feedbacks affecting host sensory systems is especially needed. For host manipulation in particular, research on mechanisms by which parasites control host feedbacks will be important to integrate with functional approaches. We see this integration as critical to advancing the field of parasite-altered feeding behavior, which may be common in insects and consequential for human and environmental health.
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Affiliation(s)
| | - Michael S Singer
- Department of Biology, Wesleyan University, Middletown, CT 06105, USA
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Microbiome Structure Influences Infection by the Parasite Crithidia bombi in Bumble Bees. Appl Environ Microbiol 2018; 84:AEM.02335-17. [PMID: 29374030 DOI: 10.1128/aem.02335-17] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 01/18/2018] [Indexed: 12/22/2022] Open
Abstract
Recent declines in bumble bee populations are of great concern and have prompted critical evaluations of the role of pathogen introductions and host resistance in bee health. One factor that may influence host resilience when facing infection is the gut microbiota. Previous experiments with Bombus terrestris, a European bumble bee, showed that the gut microbiota can protect against Crithidia bombi, a widespread trypanosomatid parasite of bumble bees. However, the particular characteristics of the microbiome responsible for this protective effect have thus far eluded identification. Using wild and commercially sourced Bombus impatiens, an important North American pollinator, we conducted cross-wise microbiota transplants to naive hosts of both backgrounds and challenged them with a Crithidia parasite. As with B. terrestris, we find that microbiota-dependent protection against Crithidia operates in B. impatiens Lower Crithidia infection loads were experimentally associated with high microbiome diversity, large gut bacterial populations, and the presence of Apibacter, Lactobacillus Firm-5, and Gilliamella spp. in the gut community. These results indicate that even subtle differences between gut community structures can have a significant impact on a microbiome's ability to defend against parasite infections.IMPORTANCE Many wild bumble bee populations are under threat due to human activity, including through the introduction of pathogens via commercially raised bees. Recently, it was found that the bumble bee gut microbiota can help defend against a common parasite, Crithidia bombi, but the particular factors contributing to this protection are unknown. Using both wild and commercially raised bees, we conducted microbiota transplants to show that microbiome diversity, total gut bacterial load, and the presence of certain core members of the microbiota may all impact bee susceptibility to Crithidia infection. Bee origin (genetic background) was also a factor. Finally, by examining this phenomenon in a previously uninvestigated bee species, our study demonstrates that microbiome-mediated resistance to Crithidia is conserved across multiple bumble bee species. These findings highlight how intricate interactions between hosts, microbiomes, and parasites can have wide-ranging consequences for the health of ecologically important species.
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Palmer-Young EC, Calhoun AC, Mirzayeva A, Sadd BM. Effects of the floral phytochemical eugenol on parasite evolution and bumble bee infection and preference. Sci Rep 2018; 8:2074. [PMID: 29391545 PMCID: PMC5794921 DOI: 10.1038/s41598-018-20369-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 01/17/2018] [Indexed: 11/09/2022] Open
Abstract
Ecological and evolutionary pressures on hosts and parasites jointly determine infection success. In pollinators, parasite exposure to floral phytochemicals may influence between-host transmission and within-host replication. In the bumble bee parasite Crithidia bombi, strains vary in phytochemical resistance, and resistance increases under in vitro selection, implying that resistance/infectivity trade-offs could maintain intraspecific variation in resistance. We assessed costs and benefits of in vitro selection for resistance to the floral phytochemical eugenol on C. bombi infection in Bombus impatiens fed eugenol-rich and eugenol-free diets. We also assessed infection-induced changes in host preferences for eugenol. In vitro, eugenol-exposed cells initially increased in size, but normalized during adaptation. Selection for eugenol resistance resulted in considerable (55%) but non-significant reductions in infection intensity; bee colony and body size were the strongest predictors of infection. Dietary eugenol did not alter infection, and infected bees preferred eugenol-free over eugenol-containing solutions. Although direct effects of eugenol exposure could influence between-host transmission at flowers, dietary eugenol did not ameliorate infection in bees. Limited within-host benefits of resistance, and possible trade-offs between resistance and infectivity, may relax selection for eugenol resistance and promote inter-strain variation in resistance. However, infection-induced dietary shifts could influence pollinator-mediated selection on floral traits.
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Affiliation(s)
- Evan C Palmer-Young
- Organismic & Evolutionary Biology Graduate Program, University of Massachusetts at Amherst, Amherst, Massachusetts, 01003, United States.
| | - Austin C Calhoun
- School of Biological Sciences, Illinois State University, Normal, Illinois, 61790, United States
| | - Anastasiya Mirzayeva
- Department of Biology, University of Massachusetts at Amherst, Amherst, Massachusetts, 01003, United States
| | - Ben M Sadd
- School of Biological Sciences, Illinois State University, Normal, Illinois, 61790, United States
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Palmer-Young EC, Tozkar CÖ, Schwarz RS, Chen Y, Irwin RE, Adler LS, Evans JD. Nectar and Pollen Phytochemicals Stimulate Honey Bee (Hymenoptera: Apidae) Immunity to Viral Infection. JOURNAL OF ECONOMIC ENTOMOLOGY 2017; 110:1959-1972. [PMID: 28981688 DOI: 10.1093/jee/tox193] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Indexed: 05/10/2023]
Affiliation(s)
| | - Cansu Ö Tozkar
- Bee Research Lab, Agricultural Research Service, US Department of Agriculture, Beltsville, MD
| | - Ryan S Schwarz
- Bee Research Lab, Agricultural Research Service, US Department of Agriculture, Beltsville, MD
| | - Yanping Chen
- Bee Research Lab, Agricultural Research Service, US Department of Agriculture, Beltsville, MD
| | - Rebecca E Irwin
- Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695
| | - Lynn S Adler
- Department of Biology, University of Massachusetts, Amherst, MA
| | - Jay D Evans
- Bee Research Lab, Agricultural Research Service, US Department of Agriculture, Beltsville, MD
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Palmer-Young EC, Hogeboom A, Kaye AJ, Donnelly D, Andicoechea J, Connon SJ, Weston I, Skyrm K, Irwin RE, Adler LS. Context-dependent medicinal effects of anabasine and infection-dependent toxicity in bumble bees. PLoS One 2017; 12:e0183729. [PMID: 28832668 PMCID: PMC5568382 DOI: 10.1371/journal.pone.0183729] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 08/09/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Floral phytochemicals are ubiquitous in nature, and can function both as antimicrobials and as insecticides. Although many phytochemicals act as toxins and deterrents to consumers, the same chemicals may counteract disease and be preferred by infected individuals. The roles of nectar and pollen phytochemicals in pollinator ecology and conservation are complex, with evidence for both toxicity and medicinal effects against parasites. However, it remains unclear how consistent the effects of phytochemicals are across different parasite lineages and environmental conditions, and whether pollinators actively self-medicate with these compounds when infected. APPROACH Here, we test effects of the nectar alkaloid anabasine, found in Nicotiana, on infection intensity, dietary preference, and survival and performance of bumble bees (Bombus impatiens). We examined variation in the effects of anabasine on infection with different lineages of the intestinal parasite Crithidia under pollen-fed and pollen-starved conditions. RESULTS We found that anabasine did not reduce infection intensity in individual bees infected with any of four Crithidia lineages that were tested in parallel, nor did anabasine reduce infection intensity in microcolonies of queenless workers. In addition, neither anabasine nor its isomer, nicotine, was preferred by infected bees in choice experiments, and infected bees consumed less anabasine than did uninfected bees under no-choice conditions. Furthermore, anabasine exacerbated the negative effects of infection on bee survival and microcolony performance. Anabasine reduced infection in only one experiment, in which bees were deprived of pollen and post-pupal contact with nestmates. In this experiment, anabasine had antiparasitic effects in bees from only two of four colonies, and infected bees exhibited reduced-rather than increased-phytochemical consumption relative to uninfected bees. CONCLUSIONS Variation in the effect of anabasine on infection suggests potential modulation of tritrophic interactions by both host genotype and environmental variables. Overall, our results demonstrate that Bombus impatiens prefer diets without nicotine and anabasine, and suggest that the medicinal effects and toxicity of anabasine may be context dependent. Future research should identify the specific environmental and genotypic factors that determine whether nectar phytochemicals have medicinal or deleterious effects on pollinators.
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Affiliation(s)
- Evan C. Palmer-Young
- Organismic & Evolutionary Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Alison Hogeboom
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Alexander J. Kaye
- Department of Biology, Dartmouth College, Hanover, New Hampshire, United States of America
| | - Dash Donnelly
- Department of Biology, Dartmouth College, Hanover, New Hampshire, United States of America
| | - Jonathan Andicoechea
- Department of Biology, Dartmouth College, Hanover, New Hampshire, United States of America
| | - Sara June Connon
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
- Department of Applied Ecology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Ian Weston
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Kimberly Skyrm
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Rebecca E. Irwin
- Department of Biology, Dartmouth College, Hanover, New Hampshire, United States of America
- Department of Applied Ecology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Lynn S. Adler
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
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Koch H, Brown MJ, Stevenson PC. The role of disease in bee foraging ecology. CURRENT OPINION IN INSECT SCIENCE 2017; 21:60-67. [PMID: 28822490 DOI: 10.1016/j.cois.2017.05.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 05/03/2017] [Accepted: 05/10/2017] [Indexed: 06/07/2023]
Abstract
Diseases have important but understudied effects on bee foraging ecology. Bees transmit and contract diseases on flowers, but floral traits including plant volatiles and inflorescence architecture may affect transmission. Diseases spill over from managed or invasive pollinators to native wild bee species, and impacts of emerging diseases are of particular concern, threatening pollinator populations and pollination services. Here we review how parasites can alter the foraging behaviour of bees by changing floral preferences and impairing foraging efficiency. We also consider how changes to pollinator behaviours alter or reduce pollination services. The availability of diverse floral resources can, however, ameliorate bee diseases and their impacts through better nutrition and antimicrobial effects of plant compounds in pollen and nectar.
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Affiliation(s)
| | - Mark Jf Brown
- School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, UK
| | - Philip C Stevenson
- Royal Botanic Gardens, Kew, Surrey, UK; Natural Resources Institute, University of Greenwich, Kent, UK
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Arnold PM, Michaels HJ. Nectar sampling for prairie and oak savanna butterfly restoration. APPLICATIONS IN PLANT SCIENCES 2017; 5:apps1600148. [PMID: 28690931 PMCID: PMC5499304 DOI: 10.3732/apps.1600148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 03/06/2017] [Indexed: 05/25/2023]
Abstract
PREMISE OF THE STUDY Understanding floral resources is vital for restoring pollinators in habitats affected by anthropogenic development and climate change. As the primary adult food, nectar can limit butterfly longevity and reproduction. For pollinator restoration, it would therefore be useful to examine nectar resources. However, because many flowers preferred by butterflies are too small for microcapillary sampling and the potential for nectar contamination can make accurate measurement difficult, we developed a modified centrifugation method to extract and separate nectar and pollen. METHODS We sampled nectar from 19 forbs using a glass wool filter to exclude potentially contaminating pollen during centrifugation. To minimize costs, we measured sugar concentration by refractometry and simple ninhydrin tests for amino acids and improved test accuracy by subsequent image analysis. Artificial nectars were used to verify the new techniques. RESULTS This method eliminated pollen from samples, while only slightly increasing sugar concentrations. Some amino acids were lost during centrifugation, but only samples with high concentrations exhibited substantial loss. We found significant differences in nectar quality among species, as well as an unexpected inverse relationship between amino acid and sugar concentrations. DISCUSSION This modified centrifugation technique is an efficient, less damaging, inexpensive approach for collecting nectar from small flowers while eliminating pollen contamination, and will facilitate restoration of declining pollinators and thereby the plants they service.
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Affiliation(s)
- Paige M. Arnold
- Department of Biological Sciences, Bowling Green State University, Bowling Green, Ohio 43403 USA
| | - Helen J. Michaels
- Department of Biological Sciences, Bowling Green State University, Bowling Green, Ohio 43403 USA
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Chan SY, Snow JW. Uptake and impact of natural diet-derived small RNA in invertebrates: Implications for ecology and agriculture. RNA Biol 2017; 14:402-414. [PMID: 27763816 PMCID: PMC5411125 DOI: 10.1080/15476286.2016.1248329] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/05/2016] [Accepted: 10/10/2016] [Indexed: 02/08/2023] Open
Abstract
The putative transfer and gene regulatory activities of diet-derived small RNAs (sRNAs) in ingesting animals are still debated. The existence of natural uptake of diet-derived sRNA by invertebrate species could have significant implication for our understanding of ecological relationships and could synergize with efforts to use RNA interference (RNAi) technology in agriculture. Here, we synthesize information gathered from studies in invertebrates using natural or artificial dietary delivery of sRNA and from studies of sRNA in vertebrate animals and plants to review our current understanding of uptake and impact of natural diet-derived sRNA on invertebrates. Our understanding has been influenced and sometimes confounded by the diversity of invertebrates and ingested plants studied, our limited insights into how gene expression may be modulated by dietary sRNAs at the mechanistic level, and the paucity of studies focusing directly on natural uptake of sRNA. As such, we suggest 2 strategies to investigate this phenomenon more comprehensively and thus facilitate the realization of its potentially broad impact on ecology and agriculture in the future.
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Affiliation(s)
- Stephen Y. Chan
- Center for Pulmonary Vascular Biology and Medicine, Pittsburgh Heart, Lung, Blood, and Vascular Medicine Institute, Department of Medicine, University of Pittsburgh School of Medicine and University of Pittsburgh Medical Center, Pittsburgh, PA, USA
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Stevenson PC, Nicolson SW, Wright GA. Plant secondary metabolites in nectar: impacts on pollinators and ecological functions. Funct Ecol 2016. [DOI: 10.1111/1365-2435.12761] [Citation(s) in RCA: 165] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Philip C. Stevenson
- Royal Botanic Gardens, Kew SurreyTW9 3AB UK
- Natural Resources Institute University of Greenwich KentME4 4TB UK
| | - Susan W. Nicolson
- Department of Zoology & Entomology University of Pretoria Private Bag X20 Hatfield0028 South Africa
| | - Geraldine A. Wright
- Centre for Behaviour and Evolution Institute of Neuroscience Newcastle University Newcastle upon TyneNE1 7RU UK
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Thorburn LP, Adler LS, Irwin RE, Palmer-Young EC. Variable effects of nicotine, anabasine, and their interactions on parasitized bumble bees. F1000Res 2015; 4:880. [PMID: 26998225 PMCID: PMC4786900 DOI: 10.12688/f1000research.6870.2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/11/2015] [Indexed: 11/20/2022] Open
Abstract
Secondary metabolites in floral nectar have been shown to reduce parasite load in two common bumble bee species. Previous studies on the effects of nectar secondary metabolites on parasitized bees have focused on single compounds in isolation; however, in nature, bees are simultaneously exposed to multiple compounds. We tested for interactions between the effects of two alkaloids found in the nectar of Nicotiana spp. plants, nicotine and anabasine, on parasite load and mortality in bumble bees ( Bombus impatiens) infected with the intestinal parasite Crithidia bombi. Adult worker bees inoculated with C. bombi were fed nicotine and anabasine diet treatments in a factorial design, resulting in four nectar treatment combinations: 2 ppm nicotine, 5 ppm anabasine, 2ppm nicotine and 5 ppm anabasine together, or a control alkaloid-free solution. We conducted the experiment twice: first, with bees incubated under variable environmental conditions ('Variable'; temperatures varied from 10-35°C with ambient lighting); and second, under carefully controlled environmental conditions ('Stable'; 27°C incubator, constant darkness). In 'Variable', each alkaloid alone significantly decreased parasite loads, but this effect was not realized with the alkaloids in combination, suggesting an antagonistic interaction. Nicotine but not anabasine significantly increased mortality, and the two compounds had no interactive effects on mortality. In 'Stable', nicotine significantly increased parasite loads, the opposite of its effect in 'Variable'. While not significant, the relationship between anabasine and parasite loads was also positive. Interactive effects between the two alkaloids on parasite load were non-significant, but the pattern of antagonistic interaction was similar to that in the variable experiment. Neither alkaloid, nor their interaction, significantly affected mortality under controlled conditions. Our results do not indicate synergy between Nicotiana nectar alkaloids; however, they do suggest a complex interaction between secondary metabolites, parasites, and environmental variables, in which secondary metabolites can be either toxic or medicinal depending on context.
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Affiliation(s)
- Lukas P Thorburn
- Department of Biology, University of Massachusetts at Amherst, Amherst, Massachusetts, USA
| | - Lynn S Adler
- Department of Biology, University of Massachusetts at Amherst, Amherst, Massachusetts, USA
| | - Rebecca E Irwin
- Department of Biology, Dartmouth College Hanover, New Hampshire, USA; Department of Applied Ecology, North Carolina State University, Raleigh, North Carolina, USA
| | - Evan C Palmer-Young
- Department of Biology, University of Massachusetts at Amherst, Amherst, Massachusetts, USA
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