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Berry JA, Braman SK, Delaplane KS, Bartlett LJ. Inducing a summer brood break increases the efficacy of oxalic acid vaporization for Varroa destructor (Mesostigmata: Varroidae) control in Apis mellifera (Hymenoptera: Apidae) colonies. J Insect Sci 2023; 23:14. [PMID: 38055946 PMCID: PMC10699866 DOI: 10.1093/jisesa/iead085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 09/10/2023] [Accepted: 09/26/2023] [Indexed: 12/08/2023]
Abstract
The ectoparasitic mite, Varroa destructor (Anderson and Trueman), is the leading cause of western honey bee colony, Apis mellifera (L.), mortality in the United States. Due to mounting evidence of resistance to certain approved miticides, beekeepers are struggling to keep their colonies alive. To date, there are varied but limited approved options for V. destructor control. Vaporized oxalic acid (OA) has proven to be an effective treatment against the dispersal phase of V. destructor but has its limitations since the vapor cannot penetrate the protective wax cap of honey bee pupal cells where V. destructor reproduces. In the Southeastern United States, honey bee colonies often maintain brood throughout the year, limiting the usefulness of OA. Prior studies have shown that even repeated applications of OA while brood is present are ineffective at decreasing mite populations. In the summer of 2021, we studied whether incorporating a forced brood break while vaporizing with OA would be an effective treatment against V. destructor. Ninety experimental colonies were divided into 2 blocks, one with a brood break and the other with no brood break. Within the blocks, each colony was randomly assigned 1 of 3 treatments: no OA, 2 g OA, or 3 g OA. The combination of vaporizing with OA and a forced brood break increased mite mortality by 5× and reduced mite populations significantly. These results give beekeepers in mild climates an additional integrated pest management method for controlling V. destructor during the summer season.
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Affiliation(s)
- Jennifer A Berry
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - S Kris Braman
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - Keith S Delaplane
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - Lewis J Bartlett
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
- Center for the Ecology of Infectious Diseases, Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
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2
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Bartlett LJ, Baker C, Bruckner S, Delaplane KS, Hackmeyer EJ, Phankaew C, Williams GR, Berry JA. No evidence to support the use of glycerol-oxalic acid mixtures delivered via paper towel for controlling Varroa destructor (Mesostigmata: Varroidae) mites in the Southeast United States. J Insect Sci 2023; 23:18. [PMID: 38055939 DOI: 10.1093/jisesa/iead097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 09/15/2023] [Accepted: 11/03/2023] [Indexed: 12/08/2023]
Abstract
A significant amount of researcher and practitioner effort has focused on developing new chemical controls for the parasitic Varroa destructor mite in beekeeping. One outcome of that has been the development and testing of "glycerol-oxalic acid" mixtures to place in colonies for extended periods of time, an off-label use of the otherwise legal miticide oxalic acid. The majority of circulated work on this approach was led by practitioners and published in nonacademic journals, highlighting a lack of effective partnership between practitioners and scientists and a possible failure of the extension mandate in beekeeping in the United States. Here, we summarize the practitioner-led studies we could locate and partner with a commercial beekeeper in the Southeast of the United States to test the "shop towel-oxalic acid-glycerol" delivery system developed by those practitioners. Our study, using 129 commercial colonies between honey flows in 2017 split into 4 treatment groups, showed no effectiveness in reducing Varroa parasitism in colonies exposed to oxalic acid-glycerol shop towels. We highlight the discrepancy between our results and those circulated by practitioners, at least for the Southeast, and the failure of extension to support practitioners engaged in research.
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Affiliation(s)
- Lewis J Bartlett
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
- Center for the Ecology of Infectious Diseases, Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
| | - Christian Baker
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA
| | - Selina Bruckner
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA
| | - Keith S Delaplane
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - Ethan J Hackmeyer
- Center for the Ecology of Infectious Diseases, Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
| | - Chama Phankaew
- Department of Entomology, Faculty of Agriculture, Kasetsart University, Chatuchuk, Bangkok 10900, Thailand
| | - Geoffrey R Williams
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA
| | - Jennifer A Berry
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
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3
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Hackmeyer EJ, Washburn TJ, Delaplane KS, Bartlett LJ. Successful application of anthranilic diamides in preventing small hive beetle (Coleoptera: Nitidulidae) infestation in honey bee (Hymenoptera: Apidae) colonies. J Insect Sci 2023; 23:12. [PMID: 38055941 PMCID: PMC10699870 DOI: 10.1093/jisesa/iead096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 08/27/2023] [Accepted: 11/03/2023] [Indexed: 12/08/2023]
Abstract
The nest-scavenging beetle Aethina tumida remains a persistent problem for beekeepers in parts of the Southeast United States, where warm wet soils allow beetle populations to grow rapidly and overwhelm colonies, especially during the summer dearth. Furthermore, small hive beetle infestation prevents beekeepers from easily provisioning colonies with additional pollen or protein feed (patties), preventing holistic management of honey bee health via improved nutrition, and reducing the economic potential of package and nucleus colony rearing in the Southeast. Here, we demonstrate using both in vitro laboratory trials and a small in vivo field trial that the differential specificity of anthranilic diamide insecticides (specifically, chlorantraniliprole) between bees and beetles allows for the control and prevention of small hive beetle infestation in honey bee colonies even when feeding with large patties. Honey bees show orders of magnitude higher tolerance to chlorantraniliprole compared to small hive beetles, opening new avenues for improving bee health including during spring splits and throughout the summer.
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Affiliation(s)
- Ethan J Hackmeyer
- Center for the Ecology of Infectious Diseases, Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
| | - Tyler J Washburn
- Department of Microbiology, Franklin College of Arts and Sciences, University of Georgia, Athens, GA 30602, USA
| | - Keith S Delaplane
- Department of Entomology, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA 30602, USA
| | - Lewis J Bartlett
- Center for the Ecology of Infectious Diseases, Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
- Department of Entomology, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA 30602, USA
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Daykin GM, Aizen MA, Barrett LG, Bartlett LJ, Batáry P, Garibaldi LA, Güncan A, Gutam S, Maas B, Mitnala J, Montaño-Centellas F, Muoni T, Öckinger E, Okechalu O, Ostler R, Potts SG, Rose DC, Topp CFE, Usieta HO, Utoblo OG, Watson C, Zou Y, Sutherland WJ, Hood ASC. AgroEcoList 1.0: A checklist to improve reporting standards in ecological research in agriculture. PLoS One 2023; 18:e0285478. [PMID: 37310957 DOI: 10.1371/journal.pone.0285478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 04/24/2023] [Indexed: 06/15/2023] Open
Abstract
Many publications lack sufficient background information (e.g. location) to be interpreted, replicated, or reused for synthesis. This impedes scientific progress and the application of science to practice. Reporting guidelines (e.g. checklists) improve reporting standards. They have been widely taken up in the medical sciences, but not in ecological and agricultural research. Here, we use a community-centred approach to develop a reporting checklist (AgroEcoList 1.0) through surveys and workshops with 23 experts and the wider agroecological community. To put AgroEcoList in context, we also assessed the agroecological community's perception of reporting standards in agroecology. A total of 345 researchers, reviewers, and editors, responded to our survey. Although only 32% of respondents had prior knowledge of reporting guidelines, 76% of those that had said guidelines improved reporting standards. Overall, respondents agreed on the need of AgroEcolist 1.0; only 24% of respondents had used reporting guidelines before, but 78% indicated they would use AgroEcoList 1.0. We updated AgroecoList 1.0 based on respondents' feedback and user-testing. AgroecoList 1.0 consists of 42 variables in seven groups: experimental/sampling set-up, study site, soil, livestock management, crop and grassland management, outputs, and finances. It is presented here, and is also available on github (https://github.com/AgroecoList/Agroecolist). AgroEcoList 1.0 can serve as a guide for authors, reviewers, and editors to improve reporting standards in agricultural ecology. Our community-centred approach is a replicable method that could be adapted to develop reporting checklists in other fields. Reporting guidelines such as AgroEcoList can improve reporting standards and therefore the application of research to practice, and we recommend that they are adopted more widely in agriculture and ecology.
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Affiliation(s)
- Georgia M Daykin
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Marcelo A Aizen
- Instituto de Investigaciones en Biodiversidad y Medio Ambiente (INIBIOMA), Universidad Nacional del Comahue - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Carlos de Bariloche, Río Negro, Argentina
| | | | - Lewis J Bartlett
- Center for the Ecology of Infectious Diseases, Odum School of Ecology, University of Georgia, Athens, Georgia, United States of America
| | - Péter Batáry
- "Lendület" Landscape and Conservation Ecology, Institute of Ecology and Botany, Centre for Ecological Research, Vácrátót, Alkomány, Hungary
| | - Lucas A Garibaldi
- Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural, Universidad Nacional de Río Negro, Viedma, Río Negro, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural, Bariloche, Río Negro, Argentina
| | - Ali Güncan
- Department of Plant Protection, Faculty of Agriculture, University of Ordu, Ordu, Turkey
| | - Sridhar Gutam
- ICAR-AICRP on Fruits, ICAR-Indian Institute of Horticultural Research, Bengaluru, Karnataka, India
| | - Bea Maas
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
- Agroecology, University of Goettingen, Göettingen, Germany
| | - Jayalakshmi Mitnala
- Regional Agricultural Research Station, Acharya N. G. Ranga Agricultural University, Hyderabad, Andhra Pradesh, India
| | - Flavia Montaño-Centellas
- Instituto de Ecología, Universidad Mayor de San Andrés, La Paz, Bolivia
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Tarirai Muoni
- CIMMYT Southern Africa Regional Office, Harare, Zimbabwe
- Department of Crop Production Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Erik Öckinger
- Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Ode Okechalu
- Department of Plant Science and Biotechnology, University of Jos, Plateau, Nigeria
| | - Richard Ostler
- Computational and Analytical Sciences, Rothamsted Research, Harpenden, United Kingdom
| | - Simon G Potts
- Centre for Agri-environmental Research, School of Agriculture, Policy and Development, University of Reading, Reading, United Kingdom
| | - David C Rose
- Centre for Agri-environmental Research, School of Agriculture, Policy and Development, University of Reading, Reading, United Kingdom
- School of Water, Energy, and Environment, Cranfield University, Cranfield, United Kingdom
| | - Cairistiona F E Topp
- Agriculture, Horticulture and Engineering Sciences, Scotland's Rural College, Edinburgh, United Kingdom
| | - Hope O Usieta
- Leventis Foundation Nigeria, F. C. T. Abuja, Nigeria
| | - Obaiya G Utoblo
- Department of Plant Science and Biotechnology, University of Jos, Plateau, Nigeria
| | - Christine Watson
- Department of Crop Production Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden
- Rural Land Use, Scotland's Rural College, Craibstone Estate, Aberdeen, United Kingdom
| | - Yi Zou
- Department of Health and Environmental Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, P. R. China
| | | | - Amelia S C Hood
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
- Centre for Agri-environmental Research, School of Agriculture, Policy and Development, University of Reading, Reading, United Kingdom
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Bartlett LJ. Frontiers in effective control of problem parasites in beekeeping. Int J Parasitol Parasites Wildl 2022; 17:263-272. [PMID: 35309040 PMCID: PMC8924282 DOI: 10.1016/j.ijppaw.2022.03.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 02/27/2022] [Accepted: 03/01/2022] [Indexed: 12/21/2022]
Abstract
Demand for better control of certain parasites in managed western honey bees (Apis mellifera L.) remains apparent amongst beekeepers in both Europe and North America, and is of widespread public, scientific, and agricultural concern. Academically, interest from numerous fields including veterinary sciences has led to many exemplary reviews of the parasites of honey bees and the treatment options available. However, summaries of current research frontiers in treating both novel and long-known parasites of managed honey bees are lacking. This review complements the currently comprehensive body of literature summarizing the effectiveness of parasite control in managed honey bees by outlining where significant gaps in development, implementation, and uptake lie, including integration into IPM frameworks and separation of cultural, biological, and chemical controls. In particular, I distinguish where challenges in identifying appropriate controls exist in the lab compared to where we encounter hurdles in technology transfer due to regulatory, economic, or cultural contexts. I overview how exciting frontiers in honey bee parasite control research are clearly demonstrated by the abundance of recent publications on novel control approaches, but also caution that temperance must be levied on the applied end of the research engine in believing that what can be achieved in a laboratory research environment can be quickly and effectively marketed for deployment in the field.
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Affiliation(s)
- Lewis J Bartlett
- Center for the Ecology of Infectious Disease, University of Georgia, Athens, GA, 30602, 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. J Insect Sci 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] [What about the content of this article? (0)] [Affiliation(s)] [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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7
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Berry JA, Bartlett LJ, Bruckner S, Baker C, Braman SK, Delaplane KS, Williams GR. Assessing Repeated Oxalic Acid Vaporization in Honey Bee (Hymenoptera: Apidae) Colonies for Control of the Ectoparasitic Mite Varroa destructor. J Insect Sci 2022; 22:15. [PMID: 35137130 PMCID: PMC8825467 DOI: 10.1093/jisesa/ieab089] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Indexed: 06/14/2023]
Abstract
The American beekeeping industry continually experiences colony mortality with annual losses as high as 43%. A leading cause of this is the exotic, ectoparasitic mite, Varroa destructor Anderson & Trueman (Mesostigmata: Varroidae). Integrated Pest Management (IPM) options are used to keep mite populations from reaching lethal levels, however, due to resistance and/or the lack of suitable treatment options, novel controls for reducing mites are warranted. Oxalic acid for controlling V. destructor has become a popular treatment regimen among commercial and backyard beekeepers. Applying vaporized oxalic acid inside a honey bee hive is a legal application method in the U.S., and results in the death of exposed mites. However, if mites are in the reproductive stage and therefore under the protective wax capping, oxalic acid is ineffective. One popular method of applying oxalic is vaporizing multiple times over several weeks to try and circumvent the problem of mites hiding in brood cells. By comparing against control colonies, we tested oxalic acid vaporization in colonies treated with seven applications separated by 5 d (35 d total). We tested in apiaries in Georgia and Alabama during 2019 and 2020, totaling 99 colonies. We found that adult honey bees Linnaeus (Hymenoptera: Apidae), and developing brood experienced no adverse impacts from the oxalic vaporization regime. However, we did not find evidence that frequent periodic application of oxalic during brood-rearing periods is capable of bringing V. destructor populations below treatment thresholds.
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Affiliation(s)
- Jennifer A Berry
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - Lewis J Bartlett
- Center for the Ecology of Infectious Diseases, University of Georgia, Athens, GA 30602, USA
| | - Selina Bruckner
- Entomology & Plant Pathology, Auburn University, Auburn, AL 36849, USA
| | - Christian Baker
- Entomology & Plant Pathology, Auburn University, Auburn, AL 36849, USA
| | - S Kris Braman
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - Keith S Delaplane
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
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Bartlett LJ, Boots M. The central role of host reproduction in determining the evolution of virulence in spatially structured populations. J Theor Biol 2021; 523:110717. [PMID: 33862089 DOI: 10.1016/j.jtbi.2021.110717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 04/05/2021] [Accepted: 04/09/2021] [Indexed: 10/21/2022]
Abstract
A substantial body of work has shown that local transmission selects for less acute, 'prudent' parasites that have lower virulence and transmission rates. This is because parasite strains with higher transmission rates 'self-shade' due to a combination of genetic correlations (self: clustered related parasite strains compete for susceptible individuals) and ecological correlations (shade: infected individuals clustering and blocking transmission). However, the interaction of ecological and genetic correlations alongside higher order ecological effects such as patch extinctions means that spatial evolutionary effects can be nuanced; theory has predicted that a relatively small proportion of local infection can select for highest virulence, such that there is a humped relationship between the degree of local infection and the harm that parasites are selected to cause. Here, we examine the separate roles of the interaction scales of reproduction and infection in the context of different degrees of pathogenic castration in determining virulence evolution outcomes. Our key result is that, as long as there is significant reproduction from infected individuals, local infection always selects for lower virulence, and that the prediction that a small proportion of local infection can select for higher virulence only occurs for highly castrating pathogens. The results emphasize the importance of demography for evolutionary outcomes in spatially structured populations, but also show that the core prediction that parasites are prudent in space is reasonable for the vast majority of host-parasite interactions and mixing patterns in nature.
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Affiliation(s)
- Lewis J Bartlett
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn TR10 9FE, UK; Center for the Ecology of Infectious Diseases, University of Georgia, Athens, GA 30602, USA.
| | - Mike Boots
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn TR10 9FE, UK; Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
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9
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Bartlett LJ, Boots M, Brosi BJ, de Roode JC, Delaplane KS, Hernandez CA, Wilfert L. Persistent effects of management history on honeybee colony virus abundances. J Invertebr Pathol 2020; 179:107520. [PMID: 33359478 DOI: 10.1016/j.jip.2020.107520] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 12/09/2020] [Accepted: 12/12/2020] [Indexed: 10/22/2022]
Abstract
Infectious diseases are a major threat to both managed and wild pollinators. One key question is how the movement or transplantation of honeybee colonies under different management regimes affects honeybee disease epidemiology. We opportunistically examined any persistent effect of colony management history following relocation by characterising the virus abundances of honeybee colonies from three management histories, representing different management histories: feral, low-intensity management, and high-intensity "industrial" management. The colonies had been maintained for one year under the same approximate 'common garden' condition. Colonies in this observational study differed in their virus abundances according to management history, with the feral population history showing qualitatively different viral abundance patterns compared to colonies from the two managed population management histories; for example, higher abundance of sacbrood virus but lower abundances of various paralysis viruses. Colonies from the high-intensity management history exhibited higher viral abundances for all viruses than colonies from the low-intensity management history. Our results provide evidence that management history has persistent impacts on honeybee disease epidemiology, suggesting that apicultural intensification could be majorly impacting on pollinator health, justifying much more substantial investigation.
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Affiliation(s)
- Lewis J Bartlett
- Centre for Ecology and Conservation, University of Exeter, TR10 9FE, UK; Department of Biology, Emory University, Atlanta, GA 30322, USA; Center for the Ecology of Infectious Diseases, University of Georgia, Athens, GA 30602, USA.
| | - Michael Boots
- Centre for Ecology and Conservation, University of Exeter, TR10 9FE, UK; Department of Integrative Biology, University of California, Berkeley, CA, 94720, USA
| | - Berry J Brosi
- Department of Environmental Sciences, Emory University, Atlanta, GA 30322, USA
| | | | - Keith S Delaplane
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - Catherine A Hernandez
- Department of Integrative Biology, University of California, Berkeley, CA, 94720, USA
| | - Lena Wilfert
- Centre for Ecology and Conservation, University of Exeter, TR10 9FE, UK; Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm D-89069, Germany
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10
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Roberts KE, Meaden S, Sharpe S, Kay S, Doyle T, Wilson D, Bartlett LJ, Paterson S, Boots M. Resource quality determines the evolution of resistance and its genetic basis. Mol Ecol 2020; 29:4128-4142. [PMID: 32860314 DOI: 10.1111/mec.15621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 07/31/2020] [Accepted: 08/05/2020] [Indexed: 10/23/2022]
Abstract
Parasites impose strong selection on their hosts, but the level of any evolved resistance may be constrained by the availability of resources. However, studies identifying the genomic basis of such resource-mediated selection are rare, particularly in nonmodel organisms. Here, we investigated the role of nutrition in the evolution of resistance to a DNA virus (PiGV), and any associated trade-offs in a lepidopteran pest species (Plodia interpunctella). Through selection experiments and whole-genome resequencing, we identify genetic markers of resistance that vary between the nutritional environments during selection. We do not find consistent evolution of resistance in the presence of virus but rather see substantial variation among replicate populations. Resistance in a low-nutrition environment is negatively correlated with growth rate, consistent with an established trade-off between immunity and development, but this relationship is highly context dependent. Whole-genome resequencing of the host shows that resistance mechanisms are likely to be highly polygenic and although the underlying genetic architecture may differ between high and low-nutrition environments, similar mechanisms are commonly used. As a whole, our results emphasize the importance of the resource environment on influencing the evolution of resistance.
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Affiliation(s)
- Katherine E Roberts
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, UK
| | - Sean Meaden
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, UK
| | - Stephen Sharpe
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, UK
| | - Suzanne Kay
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, UK
| | - Toby Doyle
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, UK
| | - Drew Wilson
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, UK
| | | | - Steve Paterson
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - Mike Boots
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, UK.,Integrative Biology, University of California, Berkeley, Berkeley, CA, USA
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11
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Bartlett LJ, Visher E, Haro Y, Roberts KE, Boots M. The target of selection matters: An established resistance-development-time negative genetic trade-off is not found when selecting on development time. J Evol Biol 2020; 33:1109-1119. [PMID: 32390292 DOI: 10.1111/jeb.13639] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 04/22/2020] [Accepted: 05/02/2020] [Indexed: 11/30/2022]
Abstract
Trade-offs are fundamental to evolutionary outcomes and play a central role in eco-evolutionary theory. They are often examined by experimentally selecting on one life-history trait and looking for negative correlations in other traits. For example, populations of the moth Plodia interpunctella selected to resist viral infection show a life-history cost with longer development times. However, we rarely examine whether the detection of such negative genetic correlations depends on the trait on which we select. Here, we examine a well-characterized negative genotypic trade-off between development time and resistance to viral infection in the moth Plodia interpunctella and test whether selection on a phenotype known to be a cost of resistance (longer development time) leads to the predicted correlated increase in resistance. If there is tight pleiotropic relationship between genes that determine development time and resistance underpinning this trade-off, we might expect increased resistance when we select on longer development time. However, we show that selecting for longer development time in this system selects for reduced resistance when compared to selection for shorter development time. This shows how phenotypes typically characterized by a trade-off can deviate from that trade-off relationship, and suggests little genetic linkage between the genes governing viral resistance and those that determine response to selection on the key life-history trait. Our results are important for both selection strategies in applied biological systems and for evolutionary modelling of host-parasite interactions.
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Affiliation(s)
- Lewis J Bartlett
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn, UK
- Center for the Ecology of Infectious Diseases, University of Georgia, Athens, GA, USA
| | - Elisa Visher
- Department of Integrative Biology, University of California, Berkeley, CA, USA
| | | | - Katherine E Roberts
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn, UK
| | - Mike Boots
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn, UK
- Department of Integrative Biology, University of California, Berkeley, CA, USA
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Bartlett LJ, Rozins C, Brosi BJ, Delaplane KS, de Roode JC, White A, Wilfert L, Boots M. Industrial bees: The impact of apicultural intensification on local disease prevalence. J Appl Ecol 2019; 56:2195-2205. [PMID: 31588148 PMCID: PMC6771535 DOI: 10.1111/1365-2664.13461] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 06/11/2019] [Indexed: 02/01/2023]
Abstract
It is generally thought that the intensification of farming will result in higher disease prevalences, although there is little specific modelling testing this idea. Focussing on honeybees, we build multi-colony models to inform how "apicultural intensification" is predicted to impact honeybee pathogen epidemiology at the apiary scale.We used both agent-based and analytical models to show that three linked aspects of apicultural intensification (increased population sizes, changes in population network structure and increased between-colony transmission) are unlikely to greatly increase disease prevalence in apiaries. Principally this is because even low-intensity apiculture exhibits high disease prevalence.The greatest impacts of apicultural intensification are found for diseases with relatively low R0 (basic reproduction number), however, such diseases cause little overall disease prevalence and, therefore, the impacts of intensification are minor. Furthermore, the smallest impacts of intensification are for diseases with high R0 values, which we argue are typical of important honeybee diseases. Policy Implications: Our findings contradict the idea that apicultural intensification by crowding honeybee colonies in large, dense apiaries leads to notably higher disease prevalences for established honeybee pathogens. More broadly, our work demonstrates the need for informative models of all agricultural systems and management practices in order to understand the implications of management changes on diseases.
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Affiliation(s)
- Lewis J. Bartlett
- Centre for Ecology and ConservationUniversity of ExeterPenrynUK
- Department of BiologyEmory UniversityAtlantaGeorgia
| | - Carly Rozins
- Centre for Ecology and ConservationUniversity of ExeterPenrynUK
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCalifornia
| | - Berry J. Brosi
- Department of Environmental SciencesEmory UniversityAtlantaGeorgia
| | | | | | - Andrew White
- Department of MathematicsHeriot‐Watt UniversityEdinburghUK
| | - Lena Wilfert
- Centre for Ecology and ConservationUniversity of ExeterPenrynUK
- Institute of Evolutionary Ecology and Conservation GenomicsUniversity of UlmUlmGermany
| | - Michael Boots
- Centre for Ecology and ConservationUniversity of ExeterPenrynUK
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCalifornia
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Bartlett LJ, Wilfert L, Boots M. A genotypic trade-off between constitutive resistance to viral infection and host growth rate. Evolution 2018; 72:2749-2757. [PMID: 30298913 PMCID: PMC6492093 DOI: 10.1111/evo.13623] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 10/05/2018] [Indexed: 02/07/2023]
Abstract
Genotypic trade‐offs are fundamental to the understanding of the evolution of life‐history traits. In particular, the evolution of optimal host defense and the maintenance of variation in defense against infectious disease is thought to be underpinned by such evolutionary trade‐offs. However, empirical demonstrations of these trade‐offs that satisfy the strict assumptions made by theoretical models are rare. Additionally, none of these trade‐offs have yet been shown to be robustly replicable using a variety of different experimental approaches to rule out confounding issues with particular experimental designs. Here, we use inbred isolines as a novel experimental approach to test whether a trade‐off between viral resistance and growth rate in Plodia interpunctella, previously demonstrated by multiple selection experiments, is robust and meets the strict criteria required to underpin theoretical work in this field. Critically, we demonstrate that this trade‐off is both genetic and constitutive. This finding helps support the large body of theory that relies on these assumptions, and makes this trade‐off for resistance unique in being replicated through multiple experimental approaches and definitively shown to be genetic and constitutive.
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Affiliation(s)
- Lewis J Bartlett
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn, United Kingdom
| | - Lena Wilfert
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn, United Kingdom
| | - Michael Boots
- Department of Integrative Biology, University of California, Berkeley, California, 94720
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Bartlett LJ, Newbold T, Purves DW, Tittensor DP, Harfoot MBJ. Synergistic impacts of habitat loss and fragmentation on model ecosystems. Proc Biol Sci 2017; 283:rspb.2016.1027. [PMID: 27655763 PMCID: PMC5046893 DOI: 10.1098/rspb.2016.1027] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 08/24/2016] [Indexed: 12/05/2022] Open
Abstract
Habitat loss and fragmentation are major threats to biodiversity, yet separating their effects is challenging. We use a multi-trophic, trait-based, and spatially explicit general ecosystem model to examine the independent and synergistic effects of these processes on ecosystem structure. We manipulated habitat by removing plant biomass in varying spatial extents, intensities, and configurations. We found that emergent synergistic interactions of loss and fragmentation are major determinants of ecosystem response, including population declines and trophic pyramid shifts. Furthermore, trait-mediated interactions, such as a disproportionate sensitivity of large-sized organisms to fragmentation, produce significant effects in shaping responses. We also show that top-down regulation mitigates the effects of land use on plant biomass loss, suggesting that models lacking these interactions—including most carbon stock models—may not adequately capture land-use change impacts. Our results have important implications for understanding ecosystem responses to environmental change, and assessing the impacts of habitat fragmentation.
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Affiliation(s)
- Lewis J Bartlett
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn, UK
| | - Tim Newbold
- United Nations Environment Programme World Conservation Monitoring Centre, Cambridge, UK
| | - Drew W Purves
- United Nations Environment Programme World Conservation Monitoring Centre, Cambridge, UK Computational Science Laboratory, Microsoft Research, Cambridge, UK
| | - Derek P Tittensor
- United Nations Environment Programme World Conservation Monitoring Centre, Cambridge, UK Computational Science Laboratory, Microsoft Research, Cambridge, UK Dalhousie University, Halifax, Nova Scotia, Canada
| | - Michael B J Harfoot
- United Nations Environment Programme World Conservation Monitoring Centre, Cambridge, UK Computational Science Laboratory, Microsoft Research, Cambridge, UK
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Knapp JL, Bartlett LJ, Osborne JL. Re-evaluating strategies for pollinator-dependent crops: How useful is parthenocarpy? J Appl Ecol 2016; 54:1171-1179. [PMID: 28781379 PMCID: PMC5516152 DOI: 10.1111/1365-2664.12813] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 10/07/2016] [Indexed: 11/29/2022]
Abstract
Whilst most studies reviewing the reliance of global agriculture on insect pollination advocate increasing the ‘supply’ of pollinators (wild or managed) to improve crop yields, there has been little focus on altering a crop's ‘demand’ for pollinators. Parthenocarpy (fruit set in the absence of fertilization) is a trait which can increase fruit quantity and quality from pollinator‐dependent crops by removing the need for pollination. Here we present a meta‐analysis of studies examining the extent and effectiveness of parthenocarpy‐promoting techniques (genetic modification, hormone application and selective breeding) currently being used commercially, or experimentally, on pollinator‐dependent crops in different test environments (no pollination, hand pollination, open pollination). All techniques significantly increased fruit quantity and quality in 18 pollinator‐dependent crop species (not including seed and nut crops as parthenocarpy causes seedlessness). The degree to which plants experienced pollen limitation in the different test environments could not be ascertained, so the absolute effect of parthenocarpy relative to optimal pollination could not be determined. Synthesis and applications. Parthenocarpy has the potential to lower a crop's demand for pollinators, whilst extending current geographic and climatic ranges of production. Thus, growers may wish to use parthenocarpic crop plants, in combination with other environmentally considerate practices, to improve food security and their economic prospects.
Parthenocarpy has the potential to lower a crop's demand for pollinators, whilst extending current geographic and climatic ranges of production. Thus, growers may wish to use parthenocarpic crop plants, in combination with other environmentally considerate practices, to improve food security and their economic prospects.
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Affiliation(s)
- Jessica L Knapp
- Environment and Sustainability Institute University of Exeter Penryn Campus Penryn Cornwall TR10 9FE UK
| | - Lewis J Bartlett
- Centre for Ecology and Conservation University of Exeter, Penryn Campus Penryn Cornwall TR10 9FE UK
| | - Juliet L Osborne
- Environment and Sustainability Institute University of Exeter Penryn Campus Penryn Cornwall TR10 9FE UK
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Abstract
Twenty "normal" volunteers underwent real-time ultrasound scanning of their submandibular salivary glands in an attempt to define the normal anatomy and ultrasound characteristics of these glands and their adjacent anatomy. It is possible to define the entire gland and portions of its duct, which measures less than 3 mm in diameter. Adjacent structures are easily seen and are constant in their relationships to the gland. Three case reports demonstrate the usefulness of this approach to various clinical problems. Real-time ultrasonography is an easily applied, non-ionizing modality to image the submandibular fossa.
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