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Fay CR, Toth AL. Is the genetic architecture of behavior exceptionally complex? Curr Opin Insect Sci 2024; 62:101167. [PMID: 38280455 DOI: 10.1016/j.cois.2024.101167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 12/15/2023] [Accepted: 01/19/2024] [Indexed: 01/29/2024]
Abstract
Are traits with high levels of plasticity more complex in their genetic architecture, as they can be modulated by numerous different environmental inputs? Many authors have assumed that behavioral traits, in part because they are highly plastic, have an exceptionally complex genetic basis. We quantitatively summarized data from 31 genome-wide association studies (GWAS) and 87 traits in Drosophila melanogaster and found no evidence that behavioral traits have fundamental differences in the number of single-nucleotide polymorphisms or the significance or effect size of those associations, compared with nonbehavioral (morphological or physiological) traits. We suggest the assertion that behavioral traits are inherently more complex on a genetic basis compared with other types of traits should not be assumed true, and merits further investigation.
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Affiliation(s)
- Cameron R Fay
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50014, USA
| | - Amy L Toth
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50014, USA.
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2
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Walton A, Toth AL. Nutritional inequalities structure worker division of labor in social insects. Curr Opin Insect Sci 2023; 58:101059. [PMID: 37230413 DOI: 10.1016/j.cois.2023.101059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 05/16/2023] [Accepted: 05/20/2023] [Indexed: 05/27/2023]
Abstract
Eusocial insect societies are fundamentally non-egalitarian. The reproductive caste 'wins' in terms of resource accumulation, whereas non-reproductive workers 'lose'. Here, we argue that the division of labor among workers is also organized by nutritional inequalities. Across vastly different social systems and a variety of hymenopteran species, there is a recurrent pattern of lean foragers and corpulent nest workers. Experimental manipulations confirm causal associations between nutritional differences, associated molecular pathways, and behavioral roles in insect societies. The comparative and functional genomic data suggest that a conserved toolkit of core metabolic, nutrient storage, and signaling genes has evolved to regulate the social insect division of labor. Thus, the unequal distribution of food resources can be considered a fundamental organizing factor in the social insect division of labor.
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Affiliation(s)
- Alexander Walton
- Biological Sciences, University of Alberta, Edmonton AB T6G 2E9, Canada
| | - Amy L Toth
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50014 USA.
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3
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Sumner S, Favreau E, Geist K, Toth AL, Rehan SM. Molecular patterns and processes in evolving sociality: lessons from insects. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220076. [PMID: 36802779 PMCID: PMC9939270 DOI: 10.1098/rstb.2022.0076] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 09/16/2022] [Indexed: 02/21/2023] Open
Abstract
Social insects have provided some of the clearest insights into the origins and evolution of collective behaviour. Over 20 years ago, Maynard Smith and Szathmáry defined the most complex form of insect social behaviour-superorganismality-among the eight major transitions in evolution that explain the emergence of biological complexity. However, the mechanistic processes underlying the transition from solitary life to superorganismal living in insects remain rather elusive. An overlooked question is whether this major transition arose via incremental or step-wise modes of evolution. We suggest that examination of the molecular processes underpinning different levels of social complexity represented across the major transition from solitary to complex sociality can help address this question. We present a framework for using molecular data to assess to what extent the mechanistic processes that take place in the major transition to complex sociality and superorganismality involve nonlinear (implying step-wise evolution) or linear (implying incremental evolution) changes in the underlying molecular mechanisms. We assess the evidence for these two modes using data from social insects and discuss how this framework can be used to test the generality of molecular patterns and processes across other major transitions. This article is part of a discussion meeting issue 'Collective behaviour through time'.
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Affiliation(s)
- Seirian Sumner
- Centre for Biodiversity and Environmental Research, Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - Emeline Favreau
- Centre for Biodiversity and Environmental Research, Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - Katherine Geist
- Department of Ecology, Evolution and Organismal Biology, and Department of Entomology, Iowa State University, Ames, IA 50011, USA
| | - Amy L. Toth
- Department of Ecology, Evolution and Organismal Biology, and Department of Entomology, Iowa State University, Ames, IA 50011, USA
| | - Sandra M. Rehan
- Department of Biology, York University, Toronto, Canada M3J 1P3
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4
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Zhang G, Murray CJ, St. Clair AL, Cass RP, Dolezal AG, Schulte LA, Toth AL, O’Neal ME. Native vegetation embedded in landscapes dominated by corn and soybean improves honey bee health and productivity. J Appl Ecol 2023. [DOI: 10.1111/1365-2664.14397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
Affiliation(s)
- Ge Zhang
- Department of Entomology Iowa State University Ames United States of America
- Department of Entomology Washington State University Pullman United States of America
| | - Caroline J. Murray
- Department of Natural Resource Ecology and Management Iowa State University Ames United States of America
| | - Ashley L. St. Clair
- Department of Entomology Iowa State University Ames United States of America
- Department of Ecology, Evolution and Organismal Biology Iowa State University Ames United States of America
- Department of Entomology University of Illinois Urbana‐Champaign Urbana United States of America
| | - Randall P. Cass
- Department of Entomology Iowa State University Ames United States of America
| | - Adam G. Dolezal
- Department of Entomology University of Illinois Urbana‐Champaign Urbana United States of America
| | - Lisa A. Schulte
- Department of Natural Resource Ecology and Management Iowa State University Ames United States of America
| | - Amy L. Toth
- Department of Entomology Iowa State University Ames United States of America
- Department of Ecology, Evolution and Organismal Biology Iowa State University Ames United States of America
| | - Matthew E. O’Neal
- Department of Entomology Iowa State University Ames United States of America
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5
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Favreau E, Geist KS, Wyatt CDR, Toth AL, Sumner S, Rehan SM. Co-expression Gene Networks and Machine-learning Algorithms Unveil a Core Genetic Toolkit for Reproductive Division of Labour in Rudimentary Insect Societies. Genome Biol Evol 2022; 15:6926469. [PMID: 36527688 PMCID: PMC9830183 DOI: 10.1093/gbe/evac174] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 12/06/2022] [Accepted: 12/10/2022] [Indexed: 12/23/2022] Open
Abstract
The evolution of eusociality requires that individuals forgo some or all their own reproduction to assist the reproduction of others in their group, such as a primary egg-laying queen. A major open question is how genes and genetic pathways sculpt the evolution of eusociality, especially in rudimentary forms of sociality-those with smaller cooperative nests when compared with species such as honeybees that possess large societies. We lack comprehensive comparative studies examining shared patterns and processes across multiple social lineages. Here we examine the mechanisms of molecular convergence across two lineages of bees and wasps exhibiting such rudimentary societies. These societies consist of few individuals and their life histories range from facultative to obligately social. Using six species across four independent origins of sociality, we conduct a comparative meta-analysis of publicly available transcriptomes. Standard methods detected little similarity in patterns of differential gene expression in brain transcriptomes among reproductive and non-reproductive individuals across species. By contrast, both supervised machine learning and consensus co-expression network approaches uncovered sets of genes with conserved expression patterns among reproductive and non-reproductive phenotypes across species. These sets overlap substantially, and may comprise a shared genetic "toolkit" for sociality across the distantly related taxa of bees and wasps and independently evolved lineages of sociality. We also found many lineage-specific genes and co-expression modules associated with social phenotypes and possible signatures of shared life-history traits. These results reveal how taxon-specific molecular mechanisms complement a core toolkit of molecular processes in sculpting traits related to the evolution of eusociality.
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Affiliation(s)
| | | | - Christopher D R Wyatt
- Department of Genetics, Environment, Evolution, University College London, London WC1E 6BT, United Kingdom
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6
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Zhang G, St. Clair AL, Dolezal AG, Toth AL, O’Neal ME. Can Native Plants Mitigate Climate-related Forage Dearth for Honey Bees (Hymenoptera: Apidae)? J Econ Entomol 2022; 115:1-9. [PMID: 34850022 PMCID: PMC8827321 DOI: 10.1093/jee/toab202] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [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: 02/14/2021] [Indexed: 06/02/2023]
Abstract
Extreme weather events, like high temperatures and droughts, are predicted to become common with climate change, and may negatively impact plant growth. How honey bees (Apis mellifera L. [Hymenoptera: Apidae]) will respond to this challenge is unclear, especially when collecting pollen, their primary source of protein, lipids, and micro-nutrients. We explored this response with a data set from multiple research projects that measured pollen collected by honey bees during 2015-2017 in which above-average temperatures and a drought occurred in 2017. We summarized the abundance and diversity of pollen collected from July to September in replicated apiaries kept at commercial soybean and corn farms in Iowa, in the Midwestern USA. The most commonly collected pollen was from clover (Trifolium spp. [Fabales: Fabaceae]), which dramatically declined in absolute and relative abundance in July 2017 during a period of high temperatures and drought. Due to an apparent lack of clover, honey bees switched to the more drought-tolerant native species (e.g., Chamaecrista fasciculata [Michx.] Greene [Fabales: Fabaceae], Dalea purpurea Vent. [Fabales: Fabaceae], Solidago spp. [Asterales: Asteraceae]), and several species of Asteraceae. This was especially noticeable in August 2017 when C. fasciculata dominated (87%) and clover disappeared from bee-collected pollen. We discuss the potential implications of climate-induced forage dearth on honey bee nutritional health. We also compare these results to a growing body of literature on the use of native, perennial flowering plants found in Midwestern prairies for the conservation of beneficial insects. We discuss the potential for drought resistant-native plants to potentially promote resilience to climate change for the non-native, managed honey bee colonies in the United States.
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Affiliation(s)
- Ge Zhang
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
- Department of Entomology, Washington State University, Pullman, WA 99163, USA
| | - Ashley L St. Clair
- Department of Entomology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - Adam G Dolezal
- Department of Entomology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - Amy L Toth
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011, USA
| | - Matthew E O’Neal
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
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7
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Affiliation(s)
- Alexander Walton
- Department of Ecology, Evolution, and Organismal Biology Iowa State University Ames IA USA
| | - Amy L. Toth
- Department of Ecology, Evolution, and Organismal Biology Iowa State University Ames IA USA
- Department of Entomology Iowa State University Ames IA USA
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8
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Borchardt KE, Morales CL, Aizen MA, Toth AL. Plant-pollinator conservation from the perspective of systems-ecology. Curr Opin Insect Sci 2021; 47:154-161. [PMID: 34325080 DOI: 10.1016/j.cois.2021.07.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/12/2021] [Accepted: 07/15/2021] [Indexed: 06/13/2023]
Abstract
Ecosystems are interconnected and complex, but conservation has often focused on rehabilitating individual species. A systems-ecology approach aims to support overall structure and maintain functions of the whole ecosystem, and may be especially pertinent for mutualistic plant-pollinator communities. This approach focuses on species interactions as the units to be conserved within the larger ecosystem. Analyzing species interactions is a more holistic approach because it incorporates a broader web of organisms, and considers the plethora of potential indirect influences from interacting partners. In this article, we suggest pollinator researchers focus on plant-pollinator networks to inform conservation programs and best support the coexistence of pollinators and plants within natural and agricultural systems. We propose that a system-ecology perspective is the most promising way to simultaneously improve pollinator conservation, agricultural sustainability, and human well-being.
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Affiliation(s)
- Kate E Borchardt
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA.
| | - Carolina L Morales
- Grupo de Ecología de la Polinización, INIBIOMA, Universidad Nacional del Comahue-CONICET, Bariloche, Río Negro, 8400, Argentina
| | - Marcelo A Aizen
- Grupo de Ecología de la Polinización, INIBIOMA, Universidad Nacional del Comahue-CONICET, Bariloche, Río Negro, 8400, Argentina; Wissenschaftskolleg zu Berlin, 14193, Berlin, Germany
| | - Amy L Toth
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA; Department of Entomology, Iowa State University, Ames, IA, 50011, USA.
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9
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Pritchard ZA, Hendriksma HP, St Clair AL, Stein DS, Dolezal AG, O’Neal ME, Toth AL. Do Viruses From Managed Honey Bees (Hymenoptera: Apidae) Endanger Wild Bees in Native Prairies? Environ Entomol 2021; 50:455-466. [PMID: 33492382 PMCID: PMC8064301 DOI: 10.1093/ee/nvaa181] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [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: 07/05/2020] [Indexed: 05/15/2023]
Abstract
Populations of wild and managed pollinators are declining in North America, and causes include increases in disease pressure and decreases in flowering resources. Tallgrass prairies can provide floral resources for managed honey bees (Hymenoptera: Apidae, Apis mellifera Linnaeus) and wild bees. Honey bees kept near prairies may compete with wild bees for floral resources, and potentially transfer viral pathogens to wild bees. Measurements of these potential interactions are lacking, especially in the context of native habitat conservation. To address this, we assessed abundance and richness of wild bees in prairies with and without honey bee hives present, and the potential spillover of several honey bee viruses to bumble bees (Hymenoptera: Apidae, Bombus Latrielle). We found no indication that the presence of honey bee hives over 2 yr had a negative effect on population size of wild bee taxa, though a potential longer-term effect remains unknown. All levels of viruses quantified in bumble bees were lower than those observed in honey bees. Higher levels of deformed wing virus and Israeli acute paralysis virus were found in Bombus griseocollis DeGeer (Hymenoptera: Apidae) collected at sites with hives than those without hives. These data suggest that the presence of honey bees in tallgrass prairie could increase wild bee exposure to viruses. Additional studies on cross-species transmission of viruses are needed to inform decisions regarding the cohabitation of managed bees within habitat utilized by wild bees.
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Affiliation(s)
- Zoe A Pritchard
- Montana Entomology Collection, Montana State University, Marsh Labs, Bozeman, MT
- Department of Ecology Evolution, and Organismal Biology, Iowa State University, Osborne Dr., Ames, IA
- Corresponding author, e-mail:
| | - Harmen P Hendriksma
- Department of Ecology Evolution, and Organismal Biology, Iowa State University, Osborne Dr., Ames, IA
| | - Ashley L St Clair
- Department of Ecology Evolution, and Organismal Biology, Iowa State University, Osborne Dr., Ames, IA
- Department of Entomology, Iowa State University, ATRB, Ames, IA
| | - David S Stein
- Department of Ecology Evolution, and Organismal Biology, Iowa State University, Osborne Dr., Ames, IA
| | - Adam G Dolezal
- Department of Entomology, University of Illinois Urbana-Champaign, Urbana, IL
| | | | - Amy L Toth
- Department of Ecology Evolution, and Organismal Biology, Iowa State University, Osborne Dr., Ames, IA
- Department of Entomology, Iowa State University, ATRB, Ames, IA
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10
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DeGrandi-Hoffman G, Corby-Harris V, Carroll M, Toth AL, Gage S, Watkins deJong E, Graham H, Chambers M, Meador C, Obernesser B. The Importance of Time and Place: Nutrient Composition and Utilization of Seasonal Pollens by European Honey Bees ( Apis mellifera L.). Insects 2021; 12:insects12030235. [PMID: 33801848 PMCID: PMC8000538 DOI: 10.3390/insects12030235] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/22/2021] [Accepted: 02/26/2021] [Indexed: 01/29/2023]
Abstract
Simple Summary Honey bees rely on pollen and nectar to provide nutrients to support their yearly colony cycle. Specifics of the cycle differ among geographic regions as do the species of flowering plants and the nutrients they provide. We examined responses of honey bees from two different queen lines fed pollens from locations that differed in floral species composition and yearly colony cycles. We detected differences between the queen lines in the amount of pollen they consumed and the size of their hypopharyngeal glands (HPG). There were also seasonal differences between the nutrient composition of pollens. Spring pollens collected from colonies in both locations had higher amino and fatty acid concentrations than fall pollens. There also were seasonal differences in responses to the pollens consumed by bees from both queen lines. Bees consumed more spring than fall pollen, but digested less of it so that bees consumed more protein from fall pollens. Though protein consumption was higher with fall pollen, HPG were larger in spring bees. Abstract Honey bee colonies have a yearly cycle that is supported nutritionally by the seasonal progression of flowering plants. In the spring, colonies grow by rearing brood, but in the fall, brood rearing declines in preparation for overwintering. Depending on where colonies are located, the yearly cycle can differ especially in overwintering activities. In temperate climates of Europe and North America, colonies reduce or end brood rearing in the fall while in warmer climates bees can rear brood and forage throughout the year. To test the hypothesis that nutrients available in seasonal pollens and honey bee responses to them can differ we analyzed pollen in the spring and fall collected by colonies in environments where brood rearing either stops in the fall (Iowa) or continues through the winter (Arizona). We fed both types of pollen to worker offspring of queens that emerged and open mated in each type of environment. We measured physiological responses to test if they differed depending on the location and season when the pollen was collected and the queen line of the workers that consumed it. Specifically, we measured pollen and protein consumption, gene expression levels (hex 70, hex 110, and vg) and hypopharyngeal gland (HPG) development. We found differences in macronutrient content and amino and fatty acids between spring and fall pollens from the same location and differences in nutrient content between locations during the same season. We also detected queen type and seasonal effects in HPG size and differences in gene expression between bees consuming spring vs. fall pollen with larger HPG and higher gene expression levels in those consuming spring pollen. The effects might have emerged from the seasonal differences in nutritional content of the pollens and genetic factors associated with the queen lines we used.
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Affiliation(s)
- Gloria DeGrandi-Hoffman
- Carl Hayden Bee Research Center, USDA Agricultural Research Service, 2000 East Allen Road, Tucson, AZ 85719, USA; (V.C.-H.); (Mark Carroll); (E.W.d.); (H.G.); (Mona Chambers); (C.M.)
- Correspondence:
| | - Vanessa Corby-Harris
- Carl Hayden Bee Research Center, USDA Agricultural Research Service, 2000 East Allen Road, Tucson, AZ 85719, USA; (V.C.-H.); (Mark Carroll); (E.W.d.); (H.G.); (Mona Chambers); (C.M.)
| | - Mark Carroll
- Carl Hayden Bee Research Center, USDA Agricultural Research Service, 2000 East Allen Road, Tucson, AZ 85719, USA; (V.C.-H.); (Mark Carroll); (E.W.d.); (H.G.); (Mona Chambers); (C.M.)
| | - Amy L. Toth
- Department of Entomology, Iowa State University, 2310 Pammel Drive, 339 Science Hall II, Ames, IA 50011, USA;
| | - Stephanie Gage
- Georgia Institute of Technology, School of Physics, Howey Physics Building, 837 State Street NW, Atlanta, GA 30313, USA;
| | - Emily Watkins deJong
- Carl Hayden Bee Research Center, USDA Agricultural Research Service, 2000 East Allen Road, Tucson, AZ 85719, USA; (V.C.-H.); (Mark Carroll); (E.W.d.); (H.G.); (Mona Chambers); (C.M.)
| | - Henry Graham
- Carl Hayden Bee Research Center, USDA Agricultural Research Service, 2000 East Allen Road, Tucson, AZ 85719, USA; (V.C.-H.); (Mark Carroll); (E.W.d.); (H.G.); (Mona Chambers); (C.M.)
| | - Mona Chambers
- Carl Hayden Bee Research Center, USDA Agricultural Research Service, 2000 East Allen Road, Tucson, AZ 85719, USA; (V.C.-H.); (Mark Carroll); (E.W.d.); (H.G.); (Mona Chambers); (C.M.)
| | - Charlotte Meador
- Carl Hayden Bee Research Center, USDA Agricultural Research Service, 2000 East Allen Road, Tucson, AZ 85719, USA; (V.C.-H.); (Mark Carroll); (E.W.d.); (H.G.); (Mona Chambers); (C.M.)
| | - Bethany Obernesser
- Department of Entomology, University of Arizona, Forbes 410, P.O. Box 210036, Tucson, AZ 85721, USA;
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Zhang G, St. Clair AL, Dolezal AG, Toth AL, O’Neal ME. North American Prairie Is a Source of Pollen for Managed Honey Bees (Hymenoptera: Apidae). J Insect Sci 2021; 21:6147288. [PMID: 33620484 PMCID: PMC7901588 DOI: 10.1093/jisesa/ieab001] [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: 06/04/2020] [Indexed: 05/08/2023]
Abstract
Prairie was a dominant habitat within large portions of North America before European settlement. Conversion of prairies to farmland resulted in the loss of a large proportion of native floral resources, contributing to the decline of native pollinator populations. Efforts to reconstruct prairie could provide honey bees (Apis mellifera) a source of much-needed forage, especially in regions dominated by crop production. To what extent honey bees, which were introduced to North America by European settlers, use plants native to prairies is unclear. We placed colonies with pollen traps within reconstructed prairies in central Iowa to determine which and how much pollen is collected from prairie plants. Honey bee colonies collected more pollen from nonnative than native plants during June and July. During August and September, honey bee colonies collected more pollen from plants native to prairies. Our results suggest that honey bees' use of native prairie plants may depend upon the seasonality of both native and nonnative plants present in the landscape. This finding may be useful for addressing the nutritional health of honey bees, as colonies in this region frequently suffer from a dearth of forage contributing to colony declines during August and September when crops and weedy plants cease blooming. These results suggest that prairie can be a significant source of forage for honey bees in the later part of the growing season in the Midwestern United States; we discuss this insight in the context of honey bee health and biodiversity conservation.
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Affiliation(s)
- Ge Zhang
- Department of Entomology, Iowa State University, Ames, IA, USA
| | - Ashley L St. Clair
- Department of Entomology, Iowa State University, Ames, IA, USA
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, USA
| | - Adam G Dolezal
- Department of Entomology, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Amy L Toth
- Department of Entomology, Iowa State University, Ames, IA, USA
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, USA
| | - Matthew E O’Neal
- Department of Entomology, Iowa State University, Ames, IA, USA
- Corresponding author,
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12
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Walton A, Sheehan MJ, Toth AL. Going wild for functional genomics: RNA interference as a tool to study gene-behavior associations in diverse species and ecological contexts. Horm Behav 2020; 124:104774. [PMID: 32422196 DOI: 10.1016/j.yhbeh.2020.104774] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 05/08/2020] [Accepted: 05/11/2020] [Indexed: 12/25/2022]
Abstract
Identifying the genetic basis of behavior has remained a challenge for biologists. A major obstacle to this goal is the difficulty of examining gene function in an ecologically relevant context. New tools such as CRISPR/Cas9, which alter the germline of an organism, have taken center stage in functional genomics in non-model organisms. However, germline modifications of this nature cannot be ethically implemented in the wild as a part of field experiments. This impediment is more than technical. Gene function is intimately tied to the environment in which the gene is expressed, especially for behavior. Most lab-based studies fail to recapitulate an organism's ecological niche, thus most published functional genomics studies of gene-behavior relationships may provide an incomplete or even inaccurate assessment of gene function. In this review, we highlight RNA interference as an especially effective experimental method to deepen our understanding of the interplay between genes, behavior, and the environment. We highlight the utility of RNAi for researchers investigating behavioral genetics, noting unique attributes of RNAi including transience of effect and the feasibility of releasing treated animals into the wild, that make it especially useful for studying the function of behavior-related genes. Furthermore, we provide guidelines for planning and executing an RNAi experiment to study behavior, including challenges to consider. We urge behavioral ecologists and functional genomicists to adopt a more fully integrated approach which we call "ethological genomics". We advocate this approach, utilizing tools such as RNAi, to study gene-behavior relationships in their natural context, arguing that such studies can provide a deeper understanding of how genes can influence behavior, as well as ecological aspects beyond the organism that houses them.
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Affiliation(s)
- Alexander Walton
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA.
| | - Michael J Sheehan
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, USA
| | - Amy L Toth
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA; Department of Entomology, Iowa State University, Ames, IA, USA
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13
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Stein DS, Debinski DM, Pleasants JM, Toth AL. Evaluating Native Bee Communities and Nutrition in Managed Grasslands. Environ Entomol 2020; 49:717-725. [PMID: 32215621 PMCID: PMC7293027 DOI: 10.1093/ee/nvaa009] [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] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Indexed: 05/08/2023]
Abstract
Native pollinators are important for providing vital services in agroecosystems; however, their numbers are declining globally. Bees are the most efficient and diverse members of the pollinator community; therefore, it is imperative that management strategies be implemented that positively affect bee community composition and health. Here, we test responses of the bee and flowering plant communities to land management treatments in the context of grasslands in the upper Midwestern United States, a critical area with respect to bee declines. Twelve sites were selected to examine floral resources and wild bee communities based on three different types of grasslands: tallgrass prairie remnants, ungrazed restorations, and grazed restorations. Total bee abundance was significantly higher in ungrazed restorations than remnants, but there were no significant differences among grasslands in community composition or Shannon diversity. Across the three grassland types we also examined mass and lipid stores as nutritional health indicators in three sweat bees (Halictidae), Augochlora pura, Agapostemon virescens, and Halictus ligatus. Although there were no differences in lipid content, total average bee mass was significantly higher in Ag. virescens collected from ungrazed restorations as compared to remnants. Floral abundance of native and non-native species combined was significantly higher in grazed restorations compared to remnants and ungrazed restorations. However, ungrazed restorations had higher abundance and richness of native flowering ramets. These data suggest that bee abundance and nutrition are driven by high abundance of native flowering plant species, rather than total flowering plants.
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Affiliation(s)
- D S Stein
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA
- Corresponding author, e-mail:
| | - D M Debinski
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA
- Department of Ecology, Montana State University, Bozeman, MT
| | - J M Pleasants
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA
| | - A L Toth
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA
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14
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St. Clair AL, Zhang G, Dolezal AG, O’Neal ME, Toth AL. Diversified Farming in a Monoculture Landscape: Effects on Honey Bee Health and Wild Bee Communities. Environ Entomol 2020; 49:753-764. [PMID: 32249293 PMCID: PMC7371362 DOI: 10.1093/ee/nvaa031] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [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: 08/21/2019] [Indexed: 05/20/2023]
Abstract
In the last century, a global transformation of Earth's surface has occurred due to human activity with extensive agriculture replacing natural ecosystems. Concomitant declines in wild and managed bees are occurring, largely due to a lack of floral resources and inadequate nutrition, caused by conversion to monoculture-based farming. Diversified fruit and vegetable farms may provide an enhanced variety of resources through crops and weedy plants, which have potential to sustain human and bee nutrition. We hypothesized fruit and vegetable farms can enhance honey bee (Hymenoptera: Apidae, Apis mellifera Linnaeus) colony growth and nutritional state over a soybean monoculture, as well as support a more diverse wild bee community. We tracked honey bee colony growth, nutritional state, and wild bee abundance, richness, and diversity in both farm types. Honey bees kept at diversified farms had increased colony weight and preoverwintering nutritional state. Regardless of colony location, precipitous declines in colony weight occurred during autumn and thus colonies were not completely buffered from the stressors of living in a matrix dominated with monocultures. Contrary to our hypothesis, wild bee diversity was greater in soybean, specifically in August, a time when fields are in bloom. These differences were largely driven by four common bee species that performed well in soybean. Overall, these results suggest fruit and vegetable farms provide some benefits for honey bees; however, they do not benefit wild bee communities. Thus, incorporation of natural habitat, rather than diversified farming, in these landscapes, may be a better choice for wild bee conservation efforts.
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Affiliation(s)
- Ashley L St. Clair
- Department of Ecology and Evolutionary Biology, Iowa State University, Ames, IA
- Department of Entomology, Iowa State University, Dr. Ames, IA
- Corresponding author, e-mail:
| | - Ge Zhang
- Department of Entomology, Iowa State University, Dr. Ames, IA
| | - Adam G Dolezal
- Department of Entomology, University of Illinois Urbana-Champaign, Urbana, IL
| | | | - Amy L Toth
- Department of Ecology and Evolutionary Biology, Iowa State University, Ames, IA
- Department of Entomology, Iowa State University, Dr. Ames, IA
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15
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St. Clair AL, Dolezal AG, O’Neal ME, Toth AL. Pan Traps for Tracking Honey Bee Activity-Density: A Case Study in Soybeans. Insects 2020; 11:insects11060366. [PMID: 32545613 PMCID: PMC7348912 DOI: 10.3390/insects11060366] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 06/09/2020] [Accepted: 06/10/2020] [Indexed: 12/16/2022]
Abstract
To study how honey bees utilize forage resources and guide pollination management plans in crops, a multitude of methods have been developed, but most are time consuming, costly, and require specialized skills. Colored pan traps for monitoring activity-density are a simple, efficient, and cost-effective alternative; however, their usefulness for studying honey bees is not well described. We examined if trap color, location within a field, and the presence of managed colonies affected estimates of honey bee activity-density within soybean fields. Soybeans are visited by pollinators but do not require these visits for seed development. Pan traps, especially those colored blue, captured more honey bees when colonies were present. There were no differences in activity-density based on placement of traps within a field nor with increasing distance from colonies. Throughout the season, activity-density in soybeans was constant but tripled after soybean ceased blooming, suggesting spikes in pan trap captures may indicate periods of forage scarcity. Activity-density did not correlate with the population size of worker bees at a site, but did correlate with number of colonies present. We conclude that pan traps can be useful for assessing honey bee activity, particularly for estimating colony presence and identifying times of forage scarcity.
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Affiliation(s)
- Ashley L. St. Clair
- Department of Ecology, Iowa State University, Evolution, and Organismal Biology, 251 Bessey Hall, Ames, IA 50011, USA;
- Correspondence:
| | - Adam G. Dolezal
- Department of Entomology, University of Illinois Urbana-Champaign, 505 S. Goodwin Ave., Urbana, IL 61801, USA;
| | - Matthew E. O’Neal
- Department of Entomology, Iowa State University, 1344 ATRB 2213 Pammel Dr., Ames, IA 50011, USA;
| | - Amy L. Toth
- Department of Ecology, Iowa State University, Evolution, and Organismal Biology, 251 Bessey Hall, Ames, IA 50011, USA;
- Department of Entomology, University of Illinois Urbana-Champaign, 505 S. Goodwin Ave., Urbana, IL 61801, USA;
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16
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Zhang G, St. Clair AL, Dolezal A, Toth AL, O’Neal M. Honey Bee (Hymenoptera: Apidea) Pollen Forage in a Highly Cultivated Agroecosystem: Limited Diet Diversity and Its Relationship to Virus Resistance. J Econ Entomol 2020; 113:1062-1072. [PMID: 32274498 PMCID: PMC7362718 DOI: 10.1093/jee/toaa055] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [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: 10/06/2019] [Indexed: 05/24/2023]
Abstract
Intensified agriculture reduces natural and seminatural habitats and plant diversity, reducing forage available to honey bees (Apis mellifera L. [Hymenoptera: Apidea]). In agricultural landscapes of Iowa, United States, we studied the impact of extrinsic agricultural intensification on the availability of pollen for honey bees by placing colonies next to soybean fields surrounded by either a low or high level of cultivation. The abundance and diversity of pollen returned to a colony were estimated by placing pollen traps on bee colonies during the summer and fall of 2015 and 2016. We observed no difference in abundance and diversity of pollen collected by colonies in either landscape, but abundance varied over time with significantly less collected in September. We explored if the most commonly collected pollen from these landscapes had the capacity to support honey bee immune health by testing if diets consisting of these pollens improved bee resistance to a viral infection. Compared to bees denied pollen, a mixture of pollen from the two most common plant taxa (Trifolium spp. L. [Fabales: Fabaceae] and Chimaechrista fasciculata (Michx.) Greene [Fabales: Fabaceae]) significantly reduced honey bee mortality induced by viral infection. These data suggest that a community of a few common plants was favored by honey bees, and when available, could be valuable for reducing mortality from a viral infection. Our data suggest a late season shortage of pollen may be ameliorated by additions of fall flowering plants, like goldenrod (Solidago spp. L. [Asterales: Asteraceae]) and sunflower (Helianthus, Heliopsis, and Silphium spp. [Asterales: Asteraceae]), as options for enhancing pollen availability and quality for honey bees in agricultural landscapes.
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Affiliation(s)
- Ge Zhang
- Department of Entomology, Iowa State University, Ames, IA
| | - Ashley L St. Clair
- Department of Entomology, Iowa State University, Ames, IA
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA
| | - Adam Dolezal
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA
- Department of Entomology, University of Illinois Urbana-Champaign, Urbana, IL
| | - Amy L Toth
- Department of Entomology, Iowa State University, Ames, IA
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA
| | - Matthew O’Neal
- Department of Entomology, Iowa State University, Ames, IA
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17
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Walton A, Tumulty JP, Toth AL, Sheehan MJ. Hormonal modulation of reproduction in Polistes fuscatus social wasps: Dual functions in both ovary development and sexual receptivity. J Insect Physiol 2020; 120:103972. [PMID: 31705844 PMCID: PMC7558460 DOI: 10.1016/j.jinsphys.2019.103972] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [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: 04/16/2019] [Revised: 11/02/2019] [Accepted: 11/04/2019] [Indexed: 06/10/2023]
Abstract
Hormones are often major regulators of complex behaviors, such as mating and reproduction. In insects, juvenile hormone (JH) is integral to many components of reproductive physiology and behavior, but its role in female sexual receptivity is not well understood. To investigate the influence of JH on receptivity, we utilized the social wasp Polistes fuscatus. In Polistes, mating behavior is temporally separated from other components of reproduction, which allows for examination of the physiology and behavior of mating, disentangled from fertilization and egg-laying. We reared virgin gynes (reproductive females) in the lab and divided them into four groups, in which gynes received multiple topical treatments of either 20 μg, 10 μg, 5 μg, or 0 μg of the JH analog methoprene. Gynes were then placed in petri dishes with 2 unrelated males and we recorded attempted and successful mating. Additionally, we measured gyne ovarian development and survival in each group. We found that methoprene increased both sexual receptivity and ovarian development, but was associated with a decrease in long-term survival. Receptivity increased linearly as methoprene treatment increased, but the effect of methoprene on ovarian development was independent of dose. These results demonstrate the importance of JH in sexual receptivity and mating behavior. We argue that the relatively understudied Polistes gyne has potential as a model for mating and reproduction, and for the internal and external regulation of this complex behavior.
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Affiliation(s)
- Alexander Walton
- Department of Neurobiology and Behavior, Cornell University, United States; Department of Ecology, Evolution, and Organismal Biology, Iowa State University, United States.
| | - James P Tumulty
- Department of Neurobiology and Behavior, Cornell University, United States
| | - Amy L Toth
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, United States
| | - Michael J Sheehan
- Department of Neurobiology and Behavior, Cornell University, United States
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18
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Dolezal AG, St Clair AL, Zhang G, Toth AL, O'Neal ME. Native habitat mitigates feast-famine conditions faced by honey bees in an agricultural landscape. Proc Natl Acad Sci U S A 2019; 116:25147-25155. [PMID: 31767769 PMCID: PMC6911205 DOI: 10.1073/pnas.1912801116] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Intensive agriculture can contribute to pollinator decline, exemplified by alarmingly high annual losses of honey bee colonies in regions dominated by annual crops (e.g., midwestern United States). As more natural or seminatural landscapes are transformed into monocultures, there is growing concern over current and future impacts on pollinators. To forecast how landscape simplification can affect bees, we conducted a replicated, longitudinal assessment of honey bee colony growth and nutritional health in an intensively farmed region where much of the landscape is devoted to production of corn and soybeans. Surprisingly, colonies adjacent to soybean fields surrounded by more cultivated land grew more during midseason than those in areas of lower cultivation. Regardless of the landscape surrounding the colonies, all experienced a precipitous decline in colony weight beginning in August and ended the season with reduced fat stores in individual bees, both predictors of colony overwintering failure. Patterns of forage availability and colony nutritional state suggest that late-season declines were caused by food scarcity during a period of extremely limited forage. To test if habitat enhancements could ameliorate this response, we performed a separate experiment in which colonies provided access to native perennials (i.e., prairie) were rescued from both weight loss and reduced fat stores, suggesting the rapid decline observed in these agricultural landscapes is not inevitable. Overall, these results show that intensively farmed areas can provide a short-term feast that cannot sustain the long-term nutritional health of colonies; reintegration of biodiversity into such landscapes may provide relief from nutritional stress.
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Affiliation(s)
- Adam G Dolezal
- Department of Entomology, University of Illinois Urbana-Champaign, Urbana, IL 61801;
| | - Ashley L St Clair
- Department of Ecology and Evolutionary Biology, Iowa State University, Ames, IA 50011
- Department of Entomology, Iowa State University, Ames, IA 50011
| | - Ge Zhang
- Department of Entomology, Iowa State University, Ames, IA 50011
| | - Amy L Toth
- Department of Ecology and Evolutionary Biology, Iowa State University, Ames, IA 50011
- Department of Entomology, Iowa State University, Ames, IA 50011
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19
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Manfredini F, Arbetman M, Toth AL. A Potential Role for Phenotypic Plasticity in Invasions and Declines of Social Insects. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00375] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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20
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Toth AL. To reproduce or work? Insect castes emerge from socially induced changes in nutrition-related genes. Mol Ecol 2019; 26:2839-2841. [PMID: 28544664 DOI: 10.1111/mec.14076] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [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: 02/08/2017] [Revised: 02/08/2017] [Accepted: 02/21/2017] [Indexed: 11/30/2022]
Abstract
In social species, there is a fundamental trade-off between 'me' and 'we'; that is, should I reproduce, or should I work to help others to reproduce? In this issue of Molecular Ecology, Okada et al. () delve into the evolution and genetic mechanisms of this core question, focusing on social caste formation in insects. The authors take advantage of a unique ant in the genus Diacamma, which has secondarily lost the classic, highly different queens and workers found in many other ants, bees and wasps. Instead, Diacamma ant castes are decided via aggressive dominance interactions among adult females, similar to dominance hierarchies seen in primitively social insects and many social vertebrates. But how does being dominated translate into reproductive shutdown and thus, the creation of a worker caste? The authors use transcriptomics to address this question, and discover that the key may lie in very rapid (within one day) changes in the regulation of nutrient signalling genes, and other genes related to nutrient storage and reproduction. In other words, being aggressed turns on or off genes that tell the ant's brain and physiology to go into 'sterile mode', whereas winning a fight stimulates other genes that ramp up reproductive traits. These results add weight to the idea that caste differences rely on a 'toolkit' of deeply conserved genes involved in core nutritional, reproductive and metabolic functions. In addition, these results emphasize the exquisite and rapid social environmental sensitivity of core toolkit genes during the production of distinct phenotypes.
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Affiliation(s)
- Amy L Toth
- Department of Ecology, Evolution, and Organismal Biology and Department of Entomology, Iowa State University, Ames, IA, 50010, USA
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21
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Rubenstein DR, Ågren JA, Carbone L, Elde NC, Hoekstra HE, Kapheim KM, Keller L, Moreau CS, Toth AL, Yeaman S, Hofmann HA. Coevolution of Genome Architecture and Social Behavior. Trends Ecol Evol 2019; 34:844-855. [PMID: 31130318 DOI: 10.1016/j.tree.2019.04.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [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: 02/05/2019] [Revised: 04/03/2019] [Accepted: 04/17/2019] [Indexed: 01/02/2023]
Abstract
Although social behavior can have a strong genetic component, it can also result in selection on genome structure and function, thereby influencing the evolution of the genome itself. Here we explore the bidirectional links between social behavior and genome architecture by considering variation in social and/or mating behavior among populations (social polymorphisms) and across closely related species. We propose that social behavior can influence genome architecture via associated demographic changes due to social living. We establish guidelines to exploit emerging whole-genome sequences using analytical approaches that examine genome structure and function at different levels (regulatory vs structural variation) from the perspective of both molecular biology and population genetics in an ecological context.
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Affiliation(s)
- Dustin R Rubenstein
- Columbia University, Department of Ecology, Evolution, and Environmental Biology and Center for Integrative Animal Behavior, New York, NY 10027, USA.
| | - J Arvid Ågren
- Harvard University, Department of Organismic and Evolutionary Biology, Cambridge, MA 02138, USA
| | - Lucia Carbone
- Oregon Health & Science University, Department of Medicine, KCVI, Portland, OR 97239, USA; Oregon National Primate Research Center, Division of Genetics, Beaverton, OR 97006, USA
| | - Nels C Elde
- University of Utah School of Medicine, Department of Human Genetics, Salt Lake City, UT 84112, USA
| | - Hopi E Hoekstra
- Harvard University, Department of Organismic and Evolutionary Biology, Cambridge, MA 02138, USA; Harvard University, Howard Hughes Medical Institute, Department of Molecular and Cellular Biology, Cambridge, MA 02138, USA
| | - Karen M Kapheim
- Utah State University, Department of Biology, Logan, UT 84322, USA
| | - Laurent Keller
- University of Lausanne, Department of Ecology and Evolution, Biophore, UNIL, 1015 Lausanne, Switzerland
| | - Corrie S Moreau
- Cornell University, Departments of Entomology and Ecology and Evolutionary Biology, Ithaca, NY 14850, USA
| | - Amy L Toth
- Iowa State University, Department of Ecology, Evolution, and Organismal Biology and Department of Entomology, Ames, IA 50011, USA
| | - Sam Yeaman
- University of Calgary, Department of Biological Sciences, Calgary, AB T2N 1N4, Canada
| | - Hans A Hofmann
- The University of Texas at Austin, Department of Integrative Biology and Institute for Cellular and Molecular Biology, 2415 Speedway C-0990, Austin, TX 78712, USA.
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22
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Rutter L, Carrillo-Tripp J, Bonning BC, Cook D, Toth AL, Dolezal AG. Transcriptomic responses to diet quality and viral infection in Apis mellifera. BMC Genomics 2019; 20:412. [PMID: 31117959 PMCID: PMC6532243 DOI: 10.1186/s12864-019-5767-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [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: 11/23/2018] [Accepted: 05/03/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Parts of Europe and the United States have witnessed dramatic losses in commercially managed honey bees over the past decade to what is considered an unsustainable extent. The large-scale loss of bees has considerable implications for the agricultural economy because bees are one of the leading pollinators of numerous crops. Bee declines have been associated with several interactive factors. Recent studies suggest nutritional and pathogen stress can interactively contribute to bee physiological declines, but the molecular mechanisms underlying interactive effects remain unknown. In this study, we provide insight into this question by using RNA-sequencing to examine how monofloral diets and Israeli acute paralysis virus inoculation influence gene expression patterns in bees. RESULTS We found a considerable nutritional response, with almost 2000 transcripts changing with diet quality. The majority of these genes were over-represented for nutrient signaling (insulin resistance) and immune response (Notch signaling and JaK-STAT pathways). In our experimental conditions, the transcriptomic response to viral infection was fairly limited. We only found 43 transcripts to be differentially expressed, some with known immune functions (argonaute-2), transcriptional regulation, and muscle contraction. We created contrasts to explore whether protective mechanisms of good diet were due to direct effects on immune function (resistance) or indirect effects on energy availability (tolerance). A similar number of resistance and tolerance candidate differentially expressed genes were found, suggesting both processes may play significant roles in dietary buffering from pathogen infection. CONCLUSIONS Through transcriptional contrasts and functional enrichment analysis, we contribute to our understanding of the mechanisms underlying feedbacks between nutrition and disease in bees. We also show that comparing results derived from combined analyses across multiple RNA-seq studies may allow researchers to identify transcriptomic patterns in bees that are concurrently less artificial and less noisy. This work underlines the merits of using data visualization techniques and multiple datasets to interpret RNA-sequencing studies.
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Affiliation(s)
- Lindsay Rutter
- Bioinformatics and Computational Biology Program, Iowa State University, Ames, 50011, IA, USA
| | - Jimena Carrillo-Tripp
- Department of Microbiology, Center for Scientific Research and Higher Education of Ensenada, Ensenada, 22860, Baja California, Mexico
| | - Bryony C Bonning
- Department of Entomology and Nematology, University of Florida, Gainesville, 32611, FL, USA
| | - Dianne Cook
- Econometrics and Business Statistics, Monash University, Clayton, 3800, VIC, Australia
| | - Amy L Toth
- Department of Entomology, Iowa State University, Ames, 50011, IA, USA.,Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, 50011, IA, USA
| | - Adam G Dolezal
- Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, 61801, IL, USA.
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23
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Hendriksma HP, Toth AL, Shafir S. Individual and Colony Level Foraging Decisions of Bumble Bees and Honey Bees in Relation to Balancing of Nutrient Needs. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00177] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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24
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Dolezal AG, Carrillo-Tripp J, Judd TM, Allen Miller W, Bonning BC, Toth AL. Interacting stressors matter: diet quality and virus infection in honeybee health. R Soc Open Sci 2019; 6:181803. [PMID: 30891288 PMCID: PMC6408407 DOI: 10.1098/rsos.181803] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 01/02/2019] [Indexed: 05/24/2023]
Abstract
Honeybee population declines have been linked to multiple stressors, including reduced diet diversity and increased exposure to understudied viral pathogens. Despite interest in these factors, few experimental studies have explored the interaction between diet diversity and viral infection in honeybees. Here, we used a mixture of laboratory cage and small semi-field nucleus hive experiments to determine how these factors interact. In laboratory experiments, we found that high-quality diets (polyfloral pollen and high-quality single-source pollen) have the potential to reduce mortality in the face of infection with Israeli acute paralysis virus (IAPV). There was a significant interaction between diet and virus infection on mortality, even in the presence of high virus titres, suggesting that good diets can help bees tolerate virus infection. Further, we found that extreme stress in the form of pollen starvation in conjunction with IAPV infection increase exiting behaviour from small experimental hives. Finally, we showed that higher-quality pollen diets have significantly higher iron and calcium content, suggesting micronutrient deficiencies could be an under-explored area of bee nutrition.
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Affiliation(s)
- Adam G. Dolezal
- Department of Entomology, University of Illinois, Urbana-Champaign, IL 61820, USA
| | - Jimena Carrillo-Tripp
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011, USA
| | - Timothy M. Judd
- Department of Biology, Southeast Missouri State University, Cape Girardeau, MO 63701, USA
| | - W. Allen Miller
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011, USA
| | - Bryony C. Bonning
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
| | - Amy L. Toth
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
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25
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Walton A, Dolezal AG, Bakken MA, Toth AL. Hungry for the queen: Honeybee nutritional environment affects worker pheromone response in a life stage‐dependent manner. Funct Ecol 2018. [DOI: 10.1111/1365-2435.13222] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alexander Walton
- Department of Ecology, Evolution, and Organismal BiologyIowa State University Ames Iowa
| | - Adam G. Dolezal
- Department of EntomologyUniversity of Illinois Urbana‐Champaign Urbana Illinois
| | - Marit A. Bakken
- School of Veterinary MedicineUniversity of Wisconsin‐Madison Madison Wisconsin
| | - Amy L. Toth
- Department of Ecology, Evolution, and Organismal BiologyIowa State University Ames Iowa
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26
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Rehan SM, Glastad KM, Steffen MA, Fay CR, Hunt BG, Toth AL. Conserved Genes Underlie Phenotypic Plasticity in an Incipiently Social Bee. Genome Biol Evol 2018; 10:2749-2758. [PMID: 30247544 PMCID: PMC6190964 DOI: 10.1093/gbe/evy212] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2018] [Indexed: 11/13/2022] Open
Abstract
Despite a strong history of theoretical work on the mechanisms of social evolution, relatively little is known of the molecular genetic changes that accompany transitions from solitary to eusocial forms. Here, we provide the first genome of an incipiently social bee that shows both solitary and social colony organization in sympatry, the Australian carpenter bee Ceratina australensis. Through comparative analysis, we provide support for the role of conserved genes and cis-regulation of gene expression in the phenotypic plasticity observed in nest-sharing, a rudimentary form of sociality. Additionally, we find that these conserved genes are associated with caste differences in advanced eusocial species, suggesting these types of mechanisms could pave the molecular pathway from solitary to eusocial living. Genes associated with social nesting in this species show signatures of being deeply conserved, in contrast to previous studies in other bees showing novel and faster-evolving genes are associated with derived sociality. Our data provide support for the idea that the earliest social transitions are driven by changes in gene regulation of deeply conserved genes.
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Affiliation(s)
- Sandra M Rehan
- Department of Biological Sciences, University of New Hampshire
| | - Karl M Glastad
- Department of Cell & Developmental Biology, University of Pennsylvania
| | | | - Cameron R Fay
- Department of Ecology, Evolution and Organismal Biology, Iowa State University
| | | | - Amy L Toth
- Department of Ecology, Evolution and Organismal Biology, Iowa State University
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Dolezal AG, Toth AL. Feedbacks between nutrition and disease in honey bee health. Curr Opin Insect Sci 2018; 26:114-119. [PMID: 29764650 DOI: 10.1016/j.cois.2018.02.006] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 12/18/2017] [Accepted: 02/02/2018] [Indexed: 05/23/2023]
Abstract
Declines in honey bee health have been attributed to multiple interacting environmental stressors; among the most important are forage/nutrition deficits and parasites and pathogens. Recent studies suggest poor honey bee nutrition can exacerbate the negative impacts of infectious viral and fungal diseases, and conversely, that common honey bee parasites and pathogens can adversely affect bee nutritional physiology. This sets up the potential for harmful feedbacks between poor nutrition and infectious disease that may contribute to spiraling declines in bee health. We suggest that improving bees' nutritional resilience should be a major goal in combating challenges to bee health; this approach can buffer bees from other environmental stressors such as pathogen infection.
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Affiliation(s)
- Adam G Dolezal
- Department of Entomology, University of Illinois at Urbana-Champaign, IL, United States.
| | - Amy L Toth
- Departments of Ecology, Evolution, and Organismal Biology and Entomology, Iowa State University, Ames, IA, United States
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28
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Berens AJ, Tibbetts EA, Toth AL. Cognitive specialization for learning faces is associated with shifts in the brain transcriptome of a social wasp. ACTA ACUST UNITED AC 2018; 220:2149-2153. [PMID: 28615487 DOI: 10.1242/jeb.155200] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [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: 12/20/2016] [Accepted: 04/03/2017] [Indexed: 01/16/2023]
Abstract
The specialized ability to learn and recall individuals based on distinct facial features is known in only a few, large-brained social taxa. Social paper wasps in the genus Polistes are the only insects known to possess this form of cognitive specialization. We analyzed genome-wide brain gene expression during facial and pattern training for two species of paper wasps (P. fuscatus, which has face recognition, and P. metricus, which does not) using RNA sequencing. We identified 237 transcripts associated with face specialization in P. fuscatus, including some transcripts involved in neuronal signaling (serotonin receptor and tachykinin). Polistes metricus that learned faces (without specialized learning) and P. fuscatus in social interactions with familiar partners (from a previous study) showed distinct sets of brain differentially expressed transcripts. These data suggest face specialization in P. fuscatus is related to shifts in the brain transcriptome associated with genes distinct from those related to general visual learning and social interactions.
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Affiliation(s)
- Ali J Berens
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Elizabeth A Tibbetts
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Amy L Toth
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA.,Department of Entomology, Iowa State University, Ames, IA 50011, USA
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29
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Manfredini F, Brown MJF, Toth AL. Candidate genes for cooperation and aggression in the social wasp Polistes dominula. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2018; 204:449-463. [PMID: 29488013 PMCID: PMC5907630 DOI: 10.1007/s00359-018-1252-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 02/09/2018] [Accepted: 02/10/2018] [Indexed: 11/28/2022]
Abstract
Cooperation and aggression are ubiquitous in social groups, and the genetic mechanisms underlying these behaviours are of great interest for understanding how social group formation is regulated and how it evolves. In this study, we used a candidate gene approach to investigate the patterns of expression of key genes for cooperation and aggression in the brain of a primitively eusocial wasp, Polistes dominula, during colony founding, when multiple foundresses can join the same nest and establish subtle hierarchies of dominance. We used a comparative approach to select candidate genes for cooperation and aggression looking at two previously published studies on global gene expression in wasps and ants. We tested the expression of these genes in P. dominula wasps that were either displaying aggressive behaviour (dominant and single foundresses) or cooperation (subordinate foundresses and workers) towards nestmates. One gene in particular, the egg yolk protein vitellogenin, known for its reproductive role in insects, displayed patterns of expression that strongly matched wasp social rank. We characterize the genomic context of vitellogenin by building a head co-expression gene network for P. dominula, and we discuss a potential role for vitellogenin as a mediator of social interactions in wasps.
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Affiliation(s)
- Fabio Manfredini
- School of Biological Sciences, Royal Holloway University of London, Egham, UK.
| | - Mark J F Brown
- School of Biological Sciences, Royal Holloway University of London, Egham, UK
| | - Amy L Toth
- Departments of Ecology, Evolution, and Organismal Biology and Entomology, Iowa State University, Ames, IA, USA
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30
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Branstetter MG, Childers AK, Cox-Foster D, Hopper KR, Kapheim KM, Toth AL, Worley KC. Genomes of the Hymenoptera. Curr Opin Insect Sci 2018; 25:65-75. [PMID: 29602364 PMCID: PMC5993429 DOI: 10.1016/j.cois.2017.11.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 11/16/2017] [Indexed: 05/06/2023]
Abstract
Hymenoptera is the second-most sequenced arthropod order, with 52 publically archived genomes (71 with ants, reviewed elsewhere), however these genomes do not capture the breadth of this very diverse order (Figure 1, Table 1). These sequenced genomes represent only 15 of the 97 extant families. Although at least 55 other genomes are in progress in an additional 11 families (see Table 2), stinging wasps represent 35 (67%) of the available and 42 (76%) of the in progress genomes. A more comprehensive catalog of hymenopteran genomes is needed for research into the evolutionary processes underlying the expansive diversity in terms of ecology, behavior, and physiological traits within this group. Additional sequencing is needed to generate an assembly for even 0.05% of the estimated 1 million hymenopteran species, and we recommend premier level assemblies for at least 0.1% of the >150,000 named species dispersed across the order. Given the haplodiploid sex determination in Hymenoptera, haploid male sequencing will help minimize genome assembly issues to enable higher quality genome assemblies.
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Affiliation(s)
- Michael G Branstetter
- Pollinating Insect-biology, Management, Systematics Research Unit, USDA-ARS, Logan, UT 84322, United States
| | - Anna K Childers
- Bee Research Laboratory, USDA-ARS, Beltsville, MD 20705, United States
| | - Diana Cox-Foster
- Pollinating Insect-biology, Management, Systematics Research Unit, USDA-ARS, Logan, UT 84322, United States
| | - Keith R Hopper
- Beneficial Insects Introduction Research Unit, USDA-ARS, Newark, DE 19713, United States
| | - Karen M Kapheim
- Utah State University, Department of Biology, Logan, UT 84322, United States
| | - Amy L Toth
- Iowa State University, Department of Ecology, Evolution, and Organismal Biology and Department of Entomology, Ames, IA 50011, United States
| | - Kim C Worley
- Human Genome Sequencing Center, and Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States
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31
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Geffre AC, Liu R, Manfredini F, Beani L, Kathirithamby J, Grozinger CM, Toth AL. Transcriptomics of an extended phenotype: parasite manipulation of wasp social behaviour shifts expression of caste-related genes. Proc Biol Sci 2017; 284:rspb.2017.0029. [PMID: 28404777 DOI: 10.1098/rspb.2017.0029] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [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: 01/05/2017] [Accepted: 03/13/2017] [Indexed: 01/17/2023] Open
Abstract
Parasites can manipulate host behaviour to increase their own transmission and fitness, but the genomic mechanisms by which parasites manipulate hosts are not well understood. We investigated the relationship between the social paper wasp, Polistes dominula, and its parasite, Xenos vesparum (Insecta: Strepsiptera), to understand the effects of an obligate endoparasitoid on its host's brain transcriptome. Previous research suggests that X. vesparum shifts aspects of host social caste-related behaviour and physiology in ways that benefit the parasitoid. We hypothesized that X. vesparum-infested (stylopized) females would show a shift in caste-related brain gene expression. Specifically, we predicted that stylopized females, who would normally be workers, would show gene expression patterns resembling pre-overwintering queens (gynes), reflecting gyne-like changes in behaviour. We used RNA-sequencing data to characterize patterns of brain gene expression in stylopized females and compared these with those of unstylopized workers and gynes. In support of our hypothesis, we found that stylopized females, despite sharing numerous physiological and life-history characteristics with members of the worker caste, show gyne-shifted brain expression patterns. These data suggest that the parasitoid affects its host by exploiting phenotypic plasticity related to social caste, thus shifting naturally occurring social behaviour in a way that is beneficial to the parasitoid.
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Affiliation(s)
- Amy C Geffre
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA
| | - Ruolin Liu
- Department of Electrical and Computer Engineering, Iowa State University, Ames, IA, USA
| | - Fabio Manfredini
- School of Biological Sciences and Centre for Systems and Synthetic Biology, Royal Holloway, University of London, London, UK
| | - Laura Beani
- Department of Biology, University of Florence, Florence, Italy
| | | | - Christina M Grozinger
- Center for Pollinator Research and Department of Entomology, Pennsylvania State University, State College, PA, USA
| | - Amy L Toth
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA .,Department of Entomology, Iowa State University, Ames, IA, USA
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32
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Toth AL, Dolezal AG. Editorial overview: Social insects: Integrative approaches to understanding insect sociality: why physiology is still highly relevant. Curr Opin Insect Sci 2017; 22:viii-ix. [PMID: 28805647 DOI: 10.1016/j.cois.2017.07.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
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33
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Jandt JM, Suryanarayanan S, Hermanson JC, Jeanne RL, Toth AL. Maternal and nourishment factors interact to influence offspring developmental trajectories in social wasps. Proc Biol Sci 2017; 284:20170651. [PMID: 28637858 PMCID: PMC5489728 DOI: 10.1098/rspb.2017.0651] [Citation(s) in RCA: 14] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 05/19/2017] [Indexed: 12/31/2022] Open
Abstract
The social and nutritional environments during early development have the potential to affect offspring traits, but the mechanisms and molecular underpinnings of these effects remain elusive. We used Polistes fuscatus paper wasps to dissect how maternally controlled factors (vibrational signals and nourishment) interact to induce different caste developmental trajectories in female offspring, leading to worker or reproductive (gyne) traits. We established a set of caste phenotype biomarkers in P. fuscatus females, finding that gyne-destined individuals had high expression of three caste-related genes hypothesized to have roles in diapause and mitochondrial metabolism. We then experimentally manipulated maternal vibrational signals (via artificial 'antennal drumming') and nourishment levels (via restricted foraging). We found that these caste-related biomarker genes were responsive to drumming, nourishment level or their interaction. Our results provide a striking example of the potent influence of maternal and nutritional effects in influencing transcriptional activity and developmental outcomes in offspring.
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Affiliation(s)
- Jennifer M Jandt
- Department of Zoology, University of Otago, Dunedin, New Zealand
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA
| | | | - John C Hermanson
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI, USA
- USDA Forest Service, Madison, WI, USA
| | - Robert L Jeanne
- Department of Zoology, University of Wisconsin-Madison, Madison, WI, USA
- Department of Entomology, University of Wisconsin-Madison, Madison, WI, USA
| | - Amy L Toth
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA
- Department of Entomology, Iowa State University, Ames, IA, USA
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Abstract
The evolution of eusociality is a perennial issue in evolutionary biology, and genomic advances have fueled steadily growing interest in the genetic changes underlying social evolution. Along with a recent flurry of research on comparative and evolutionary genomics in different eusocial insect groups (bees, ants, wasps, and termites), several mechanistic explanations have emerged to describe the molecular evolution of eusociality from solitary behavior. These include solitary physiological ground plans, genetic toolkits of deeply conserved genes, evolutionary changes in protein-coding genes, cis regulation, and the structure of gene networks, epigenetics, and novel genes. Despite this proliferation of ideas, there has been little synthesis, even though these ideas are not mutually exclusive and may in fact be complementary. We review available data on molecular evolution of insect sociality and highlight key biotic and abiotic factors influencing social insect genomes. We then suggest both phylogenetic and ecological evolutionary developmental biology (eco-evo-devo) perspectives for a more synthetic view of molecular evolution in insect societies.
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Affiliation(s)
- Amy L Toth
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa 50011;
- Department of Entomology, Iowa State University, Ames, Iowa 50011
| | - Sandra M Rehan
- Department of Biological Sciences, University of New Hampshire, Durham, New Hampshire 03824;
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35
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Dolezal AG, Hendrix SD, Scavo NA, Carrillo-Tripp J, Harris MA, Wheelock MJ, O’Neal ME, Toth AL. Honey Bee Viruses in Wild Bees: Viral Prevalence, Loads, and Experimental Inoculation. PLoS One 2016; 11:e0166190. [PMID: 27832169 PMCID: PMC5104440 DOI: 10.1371/journal.pone.0166190] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 10/24/2016] [Indexed: 11/26/2022] Open
Abstract
Evidence of inter-species pathogen transmission from managed to wild bees has sparked concern that emerging diseases could be causing or exacerbating wild bee declines. While some pathogens, like RNA viruses, have been found in pollen and wild bees, the threat these viruses pose to wild bees is largely unknown. Here, we tested 169 bees, representing 4 families and 8 genera, for five common honey bee (Apis mellifera) viruses, finding that more than 80% of wild bees harbored at least one virus. We also quantified virus titers in these bees, providing, for the first time, an assessment of viral load in a broad spectrum of wild bees. Although virus detection was very common, virus levels in the wild bees were minimal—similar to or lower than foraging honey bees and substantially lower than honey bees collected from hives. Furthermore, when we experimentally inoculated adults of two different bee species (Megachile rotundata and Colletes inaequalis) with a mixture of common viruses that is lethal to honey bees, we saw no effect on short term survival. Overall, we found that honey bee RNA viruses can be commonly detected at low levels in many wild bee species, but we found no evidence that these pathogens cause elevated short-term mortality effects. However, more work on these viruses is greatly needed to assess effects on additional bee species and life stages.
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Affiliation(s)
- Adam G. Dolezal
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, United States of America
- * E-mail:
| | - Stephen D. Hendrix
- Department of Biology, University of Iowa, Iowa City, Iowa, United States of America
| | - Nicole A. Scavo
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, United States of America
| | - Jimena Carrillo-Tripp
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, United States of America
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, Iowa, United States of America
| | - Mary A. Harris
- Department of Natural Resource Ecology and Management, Iowa State University, Ames, Iowa, United States of America
| | - M. Joseph Wheelock
- Department of Entomology, Iowa State University, Ames, Iowa, United States of America
| | - Matthew E. O’Neal
- Department of Entomology, Iowa State University, Ames, Iowa, United States of America
| | - Amy L. Toth
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, United States of America
- Department of Entomology, Iowa State University, Ames, Iowa, United States of America
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36
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Toth AL, Sumner S, Jeanne RL. Patterns of longevity across a sociality gradient in vespid wasps. Curr Opin Insect Sci 2016; 16:28-35. [PMID: 27720047 DOI: 10.1016/j.cois.2016.05.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 05/04/2016] [Accepted: 05/06/2016] [Indexed: 06/06/2023]
Abstract
The reversal of the fecundity/longevity tradeoff in social insects is striking, but we lack understanding of when and how this reversal evolved. Vespid wasps are excellent models for studying social evolution because species show different levels of sociality from solitary to primitively to advanced eusocial. We provide the first synthesis of existing, but scanty, data available on longevity in vespids. We explore whether the fecundity/longevity tradeoff reversal is exaggerated in species with more derived sociality. Although the reversal is evident in primitively social wasps, the available data suggest it may be stronger in large-colonied species, which show a trend toward shorter worker longevity. More data are needed on additional species and underlying mechanisms, but vespids hold promise for understanding the evolution of the fecundity/longevity tradeoff reversal.
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Affiliation(s)
- Amy L Toth
- Departments of Ecology, Evolution, and Organismal Biology and Entomology, Iowa State University, USA.
| | - Seirian Sumner
- School of Biological Sciences, University of Bristol, UK
| | - Robert L Jeanne
- Department of Entomology, University of Wisconsin-Madison, USA
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37
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Dolezal AG, Carrillo-Tripp J, Miller WA, Bonning BC, Toth AL. Intensively Cultivated Landscape and Varroa Mite Infestation Are Associated with Reduced Honey Bee Nutritional State. PLoS One 2016; 11:e0153531. [PMID: 27070422 PMCID: PMC4829173 DOI: 10.1371/journal.pone.0153531] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 03/30/2016] [Indexed: 12/25/2022] Open
Abstract
As key pollinators, honey bees are crucial to many natural and agricultural ecosystems. An important factor in the health of honey bees is the availability of diverse floral resources. However, in many parts of the world, high-intensity agriculture could result in a reduction in honey bee forage. Previous studies have investigated how the landscape surrounding honey bee hives affects some aspects of honey bee health, but to our knowledge there have been no investigations of the effects of intensively cultivated landscapes on indicators of individual bee health such as nutritional physiology and pathogen loads. Furthermore, agricultural landscapes in different regions vary greatly in forage and land management, indicating a need for additional information on the relationship between honey bee health and landscape cultivation. Here, we add to this growing body of information by investigating differences in nutritional physiology between honey bees kept in areas of comparatively low and high cultivation in an area generally high agricultural intensity in the Midwestern United States. We focused on bees collected directly before winter, because overwintering stress poses one of the most serious problems for honey bees in temperate climates. We found that honey bees kept in areas of lower cultivation exhibited higher lipid levels than those kept in areas of high cultivation, but this effect was observed only in colonies that were free of Varroa mites. Furthermore, we found that the presence of mites was associated with lower lipid levels and higher titers of deformed wing virus (DWV), as well as a non-significant trend towards higher overwinter losses. Overall, these results show that mite infestation interacts with landscape, obscuring the effects of landscape alone and suggesting that the benefits of improved foraging landscape could be lost without adequate control of mite infestations.
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Affiliation(s)
- Adam G Dolezal
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, United States of America
- * E-mail:
| | - Jimena Carrillo-Tripp
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, United States of America
| | - W. Allen Miller
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, United States of America
| | - Bryony C. Bonning
- Department of Entomology, Iowa State University, Ames, IA, United States of America
| | - Amy L. Toth
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, United States of America
- Department of Entomology, Iowa State University, Ames, IA, United States of America
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38
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Smith GW, Debinski DM, Scavo NA, Lange CJ, Delaney JT, Moranz RA, Miller JR, Engle DM, Toth AL. Bee Abundance and Nutritional Status in Relation to Grassland Management Practices in an Agricultural Landscape. Environ Entomol 2016; 45:338-347. [PMID: 26921883 DOI: 10.1093/ee/nvw005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [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: 08/26/2015] [Accepted: 01/19/2016] [Indexed: 06/05/2023]
Abstract
Grasslands provide important resources for pollinators in agricultural landscapes. Managing grasslands with fire and grazing has the potential to benefit plant and pollinator communities, though there is uncertainty about the ideal approach. We examined the relationships among burning and grazing regimes, plant communities, and Bombus species and Apis mellifera L. abundance and nutritional indicators at the Grand River Grasslands in southern Iowa and northern Missouri. Treatment regimes included burn-only, grazed-and-burned, and patch-burn graze (pastures subdivided into three temporally distinct fire patches with free access by cattle). The premise of the experimental design was that patch-burn grazing would increase habitat heterogeneity, thereby providing more diverse and abundant floral resources for pollinators. We predicted that both bee abundance and individual bee nutritional indicators (bee size and lipid content) would be positively correlated with floral resource abundance. There were no significant differences among treatments with respect to bee abundance. However, some of the specific characteristics of the plant community showed significant relationships with bee response variables. Pastures with greater abundance of floral resources had greater bee abundance but lower bee nutritional indicators. Bee nutritional variables were positively correlated with vegetation height, but, in some cases, negatively correlated with stocking rate. These results suggest grassland site characteristics such as floral resource abundance and stocking rate are of potential importance to bee pollinators and suggest avenues for further research to untangle the complex interactions between grassland management, plant responses, and bee health.
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Affiliation(s)
- Griffin W Smith
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011 (; ; ; ; ; ; )
| | - Diane M Debinski
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011 (; ; ; ; ; ; )
| | - Nicole A Scavo
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011 (; ; ; ; ; ; )
| | - Corey J Lange
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011 (; ; ; ; ; ; )
| | - John T Delaney
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011 (; ; ; ; ; ; )
| | - Raymond A Moranz
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011 (; ; ; ; ; ; )
| | - James R Miller
- Department of Natural Resources and Environmental Sciences, University of Illinois, Urbana, IL 61801
| | - David M Engle
- Department of Natural Resource Ecology and Management, Oklahoma State University, Stillwater, OK 74078
| | - Amy L Toth
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011 (; ; ; ; ; ; ),
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Standage DS, Berens AJ, Glastad KM, Severin AJ, Brendel VP, Toth AL. Genome, transcriptome and methylome sequencing of a primitively eusocial wasp reveal a greatly reduced DNA methylation system in a social insect. Mol Ecol 2016; 25:1769-84. [PMID: 26859767 DOI: 10.1111/mec.13578] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [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: 11/23/2015] [Revised: 01/07/2016] [Accepted: 01/18/2016] [Indexed: 01/04/2023]
Abstract
Comparative genomics of social insects has been intensely pursued in recent years with the goal of providing insights into the evolution of social behaviour and its underlying genomic and epigenomic basis. However, the comparative approach has been hampered by a paucity of data on some of the most informative social forms (e.g. incipiently and primitively social) and taxa (especially members of the wasp family Vespidae) for studying social evolution. Here, we provide a draft genome of the primitively eusocial model insect Polistes dominula, accompanied by analysis of caste-related transcriptome and methylome sequence data for adult queens and workers. Polistes dominula possesses a fairly typical hymenopteran genome, but shows very low genomewide GC content and some evidence of reduced genome size. We found numerous caste-related differences in gene expression, with evidence that both conserved and novel genes are related to caste differences. Most strikingly, these -omics data reveal a major reduction in one of the major epigenetic mechanisms that has been previously suggested to be important for caste differences in social insects: DNA methylation. Along with a conspicuous loss of a key gene associated with environmentally responsive DNA methylation (the de novo DNA methyltransferase Dnmt3), these wasps have greatly reduced genomewide methylation to almost zero. In addition to providing a valuable resource for comparative analysis of social insect evolution, our integrative -omics data for this important behavioural and evolutionary model system call into question the general importance of DNA methylation in caste differences and evolution in social insects.
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Affiliation(s)
- Daniel S Standage
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
| | - Ali J Berens
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, 50011, USA
| | - Karl M Glastad
- School of Biology, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Andrew J Severin
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, 50011, USA.,Office of Biotechnology, Iowa State University, Ames, IA, 50011, USA
| | - Volker P Brendel
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA.,School of Informatics and Computing, Indiana University, Bloomington, IN, 47405, USA
| | - Amy L Toth
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, 50011, USA.,Department of Entomology, Iowa State University, Ames, IA, 50011, USA
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40
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Carrillo-Tripp J, Dolezal AG, Goblirsch MJ, Miller WA, Toth AL, Bonning BC. In vivo and in vitro infection dynamics of honey bee viruses. Sci Rep 2016; 6:22265. [PMID: 26923109 PMCID: PMC4770293 DOI: 10.1038/srep22265] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 02/10/2016] [Indexed: 12/20/2022] Open
Abstract
The honey bee (Apis mellifera) is commonly infected by multiple viruses. We developed an experimental system for the study of such mixed viral infections in newly emerged honey bees and in the cell line AmE-711, derived from honey bee embryos. When inoculating a mixture of iflavirids [sacbrood bee virus (SBV), deformed wing virus (DWV)] and dicistrovirids [Israeli acute paralysis virus (IAPV), black queen cell virus (BQCV)] in both live bee and cell culture assays, IAPV replicated to higher levels than other viruses despite the fact that SBV was the major component of the inoculum mixture. When a different virus mix composed mainly of the dicistrovirid Kashmir bee virus (KBV) was tested in cell culture, the outcome was a rapid increase in KBV but not IAPV. We also sequenced the complete genome of an isolate of DWV that covertly infects the AmE-711 cell line, and found that this virus does not prevent IAPV and KBV from accumulating to high levels and causing cytopathic effects. These results indicate that different mechanisms of virus-host interaction affect virus dynamics, including complex virus-virus interactions, superinfections, specific virus saturation limits in cells and virus specialization for different cell types.
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Affiliation(s)
- Jimena Carrillo-Tripp
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011, USA
| | - Adam G. Dolezal
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA
| | | | - W. Allen Miller
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011, USA
| | - Amy L. Toth
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
| | - Bryony C. Bonning
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
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Dolezal AG, Carrillo-Tripp J, Miller WA, Bonning BC, Toth AL. Pollen Contaminated With Field-Relevant Levels of Cyhalothrin Affects Honey Bee Survival, Nutritional Physiology, and Pollen Consumption Behavior. J Econ Entomol 2016; 109:41-8. [PMID: 26476556 DOI: 10.1093/jee/tov301] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Honey bees are exposed to a variety of environmental factors that impact their health, including nutritional stress, pathogens, and pesticides. In particular, there has been increasing evidence that sublethal exposure to pesticides can cause subtle, yet important effects on honey bee health and behavior. Here, we add to this body of knowledge by presenting data on bee-collected pollen containing sublethal levels of cyhalothrin, a pyrethroid insecticide, which, when fed to young honey bees, resulted in significant changes in lifespan, nutritional physiology,and behavior. For the first time, we show that when young, nest-aged bees are presented with pollen containing field-relevant levels of cyhalothrin, they reduce their consumption of contaminated pollen. This indicates that, at least for some chemicals, young bees are able to detect contamination in pollen and change their behavioral response, even if the contamination levels do not prevent foraging honey bees from collecting the contaminated pollen.
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Berens AJ, Tibbetts EA, Toth AL. Candidate genes for individual recognition in Polistes fuscatus paper wasps. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2015; 202:115-29. [PMID: 26660069 DOI: 10.1007/s00359-015-1057-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Revised: 11/12/2015] [Accepted: 11/13/2015] [Indexed: 12/22/2022]
Abstract
Few animals are known to individually recognize conspecifics, i.e. learn and recall unique individuals during subsequent encounters, and nearly all are social vertebrates. Remarkably, the social paper wasp Polistes fuscatus has recently been discovered to possess this ability, which is useful for remembering identities during competitive social interactions. We analyzed brain gene expression in staged encounters between pairs of individuals to explore potential mechanisms underlying wasps' ability to recall familiar individuals using real-time qRT-PCR. We identified four candidate genes (IP3K, IP3R, Nckx30C and Su(var)2-10) that were down-regulated in the presence of familiar individuals compared to single wasps and pairs of wasps meeting for the first time. These candidate genes are related to calcium signaling, therefore, we treated wasps with lithium chloride, a pharmacological agent that inhibits calcium signaling in neurons. This treatment decreased aggression in paper wasps, but did not affect expression of genes related to calcium signaling. The results suggest calcium signaling differences may be related to individual memory recall in wasps, and we present four promising candidate genes for future study. These data suggest genes associated with dominance behavior may be co-opted for individual recognition, but further work is needed to establish a causal association with the behavior.
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Affiliation(s)
- A J Berens
- Program in Bioinformatics and Computational Biology, Iowa State University, Ames, IA, 50011, USA.
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, 50011, USA.
| | - E A Tibbetts
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - A L Toth
- Program in Bioinformatics and Computational Biology, Iowa State University, Ames, IA, 50011, USA
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, 50011, USA
- Department of Entomology, Iowa State University, Ames, IA, 50011, USA
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Sheehan MJ, Botero CA, Hendry TA, Sedio BE, Jandt JM, Weiner S, Toth AL, Tibbetts EA. Different axes of environmental variation explain the presence vs. extent of cooperative nest founding associations in Polistes paper wasps. Ecol Lett 2015; 18:1057-67. [PMID: 26248800 DOI: 10.1111/ele.12488] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [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: 06/08/2015] [Accepted: 07/08/2015] [Indexed: 11/26/2022]
Abstract
Ecological constraints on independent breeding are recognised as major drivers of cooperative breeding across diverse lineages. How the prevalence and degree of cooperative breeding relates to ecological variation remains unresolved. Using a large data set of cooperative nesting in Polistes wasps we demonstrate that different aspects of cooperative breeding are likely to be driven by different aspects of climate. Whether or not a species forms cooperative groups is associated with greater short-term temperature fluctuations. In contrast, the number of cooperative foundresses increases in more benign environments with warmer, wetter conditions. The same data set reveals that intraspecific responses to climate variation do not mirror genus-wide trends and instead are highly heterogeneous among species. Collectively these data suggest that the ecological drivers that lead to the origin or loss of cooperation are different from those that influence the extent of its expression within populations.
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Affiliation(s)
- Michael J Sheehan
- Integrative Biology and Museum of Vertebrate Zoology, UC Berkeley, Berkeley, CA, 94720, USA.,Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA.,Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Carlos A Botero
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, 63130, USA.,Initiative for Biological Complexity, North Carolina State University, Raleigh, NC, 27695, USA
| | - Tory A Hendry
- Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, 48109, USA.,Environmental Science, Policy, and Management, UC Berkeley, Berkeley, CA, 94720, USA
| | - Brian E Sedio
- Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, 48109, USA.,Smithsonian Tropical Research Institute, Balboa, Ancon, Panamá
| | - Jennifer M Jandt
- Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, 50011, USA
| | - Susan Weiner
- Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, IL, 60605, USA
| | - Amy L Toth
- Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, 50011, USA
| | - Elizabeth A Tibbetts
- Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, 48109, USA
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Rehan SM, Toth AL. Climbing the social ladder: the molecular evolution of sociality. Trends Ecol Evol 2015; 30:426-33. [PMID: 26051561 DOI: 10.1016/j.tree.2015.05.004] [Citation(s) in RCA: 128] [Impact Index Per Article: 14.2] [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: 03/02/2015] [Revised: 05/11/2015] [Accepted: 05/12/2015] [Indexed: 11/24/2022]
Abstract
Genomic tools are allowing us to dissect the roles of genes and genetic architecture in social evolution, and eusocial insects are excellent models. Numerous hypotheses for molecular evolution of eusociality have been proposed, ranging from regulatory shifts in 'old' genes to rapid evolution of 'new' genes. A broad model to explain this major transition in evolution has been lacking. We provide a synthetic framework centered on the idea that different evolutionary processes dominate during different transitional stages, beginning with changes in gene regulation and culminating in novel genes later on. By considering multiple mechanisms as we 'climb the social ladder', we can test whether the transitions from solitary to simple sociality to complex sociality represent incremental changes or genetic revolutions.
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Affiliation(s)
- Sandra M Rehan
- Department of Biological Sciences, University of New Hampshire, Durham, NH 03824, USA.
| | - Amy L Toth
- Department of Evolution, Ecology, and Organismal Biology, and Department of Entomology, Iowa State University, Ames, IA 50011, USA
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Abstract
Background Social insects exhibit striking phenotypic plasticity in the form of distinct reproductive (queen) and non-reproductive (worker) castes, which are typically driven by differences in the environment during early development. Nutritional environment and nourishment during development has been shown to be broadly associated with caste determination across social insect taxa such as bees, wasps, and termites. In primitively social insects such as Polistes paper wasps, caste remains flexible throughout adulthood, but there is evidence that nourishment inequalities can bias caste development with workers receiving limited nourishment compared to queens. Dominance and vibrational signaling are behaviors that have also been linked to caste differences in paper wasps, suggesting that a combination of nourishment and social factors may drive caste determination. To better understand the molecular basis of nutritional effects on caste determination, we used RNA-sequencing to investigate the gene expression changes in response to proteinaceous nourishment deprivation in Polistes metricus larvae. Results We identified 285 nourishment-responsive transcripts, many of which are related to lipid metabolism and oxidation-reduction activity. Via comparisons to previously identified caste-related genes, we found that nourishment restriction only partially biased wasp gene expression patterns toward worker caste-like traits, which supports the notion that nourishment, in conjunction with social environment, is a determinant of developmental caste bias. In addition, we conducted cross-species comparisons of nourishment-responsive genes, and uncovered largely lineage-specific gene expression changes, suggesting few shared nourishment-responsive genes across taxa. Conclusion Overall, the results from this study highlight the complex and multifactorial nature of environmental effects on the gene expression patterns underlying plastic phenotypes. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1410-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ali J Berens
- Program in Bioinformatics and Computational Biology, Iowa State University, Ames, IA, 50011, USA. .,Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, 50011, USA.
| | - James H Hunt
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, 27695, USA. .,Department of Entomology, North Carolina State University, Raleigh, NC, 27695, USA. .,W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC, 27695, USA.
| | - Amy L Toth
- Program in Bioinformatics and Computational Biology, Iowa State University, Ames, IA, 50011, USA. .,Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, 50011, USA. .,Department of Entomology, Iowa State University, Ames, IA, 50011, USA.
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Berens AJ, Hunt JH, Toth AL. Comparative Transcriptomics of Convergent Evolution: Different Genes but Conserved Pathways Underlie Caste Phenotypes across Lineages of Eusocial Insects. Mol Biol Evol 2014; 32:690-703. [DOI: 10.1093/molbev/msu330] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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Rehan SM, Berens AJ, Toth AL. At the brink of eusociality: transcriptomic correlates of worker behaviour in a small carpenter bee. BMC Evol Biol 2014; 14:260. [PMID: 25514967 PMCID: PMC4276265 DOI: 10.1186/s12862-014-0260-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 12/08/2014] [Indexed: 01/28/2023] Open
Abstract
Background There is great interest in understanding the genomic underpinnings of social evolution, in particular, the evolution of eusociality (caste-containing societies with non-reproductives that care for siblings). Subsociality is a key precursor for the evolution of eusociality and characterized by prolonged parental care and parent-offspring interaction. Here, we provide the first transcriptomic data for the small carpenter bee, Ceratina calcarata. This species is of special interest because it is subsocial and in the same family as the highly eusocial honey bee, Apis mellifera. In addition, some C. calcarata females demonstrate alloparental care without reproduction, which provides a unique opportunity to study worker behaviour in a non-eusocial species. Results We uncovered similar gene expression patterns related to maternal care and sibling care in different groups of females. This agrees with the maternal heterochrony hypothesis, specifically, that changes in timing of offspring care gene expression are related to worker behaviour in incipient insect societies. In addition, we also detected some similarity to caste-related gene expression patterns in highly eusocial honey bees, and uncovered large lifetime changes in gene expression that accompany shifts in reproductive and maternal care behaviour. Conclusions For Ceratina calcarata, we found that transcript expression profiles were most similar between sibling care and maternal care females. The maternal care behaviour exhibited post-reproductively by Ceratina mothers is concordant in terms of transcript expression with the alloparental care exhibited by workers. In line with theoretical predictions, our data are consistent with the maternal heterochrony hypothesis for the evolutionary development of worker behaviour in subsocial bees. Electronic supplementary material The online version of this article (doi:10.1186/s12862-014-0260-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sandra M Rehan
- Department of Biological Sciences, University of New Hampshire, Durham, New Hampshire, USA.
| | - Ali J Berens
- Program in Bioinformatics and Computational Biology, Iowa State University, Ames, Iowa, USA. .,Department of Evolution, Ecology, and Organismal Biology, Iowa State University, Ames, Iowa, USA.
| | - Amy L Toth
- Program in Bioinformatics and Computational Biology, Iowa State University, Ames, Iowa, USA. .,Department of Evolution, Ecology, and Organismal Biology, Iowa State University, Ames, Iowa, USA. .,Department of Entomology, Iowa State University, Ames, Iowa, USA.
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Roy Chowdhury N, Cook D, Hofmann H, Majumder M, Lee EK, Toth AL. Using visual statistical inference to better understand random class separations in high dimension, low sample size data. Comput Stat 2014. [DOI: 10.1007/s00180-014-0534-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Carrillo-Tripp J, Krueger EN, Harrison RL, Toth AL, Miller WA, Bonning BC. Lymantria dispar iflavirus 1 (LdIV1), a new model to study iflaviral persistence in lepidopterans. J Gen Virol 2014; 95:2285-2296. [DOI: 10.1099/vir.0.067710-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The cell line IPLB-LD-652Y, derived from the gypsy moth (Lymantria dispar L.), is routinely used to study interactions between viruses and insect hosts. Here we report the full genome sequence and biological characteristics of a small RNA virus, designated Lymantria dispar iflavirus 1 (LdIV1), that was discovered to persistently infect IPLB-LD-652Y. LdIV1 belongs to the genus Iflavirus. LdIV1 formed icosahedral particles of approx. 30 nm in diameter and contained a 10 044 nt polyadenylated, positive-sense RNA genome encoding a predicted polyprotein of 2980 aa. LdIV1 was induced by a viral suppressor of RNA silencing, suggesting that acute infection is restricted by RNA interference (RNAi). We detected LdIV1 in all tested tissues of gypsy-moth larvae and adults, but the virus was absent from other L. dispar-derived cell lines. We confirmed LdIV1 infectivity in two of these cell lines (IPLB-LD-652 and IPLB-LdFB). Our results provide a novel system to explore persistent infections in lepidopterans and a new model for the study of iflaviruses, a rapidly expanding group of viruses, many of which covertly infect their hosts.
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Affiliation(s)
- Jimena Carrillo-Tripp
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011, USA
| | - Elizabeth N. Krueger
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011, USA
| | - Robert L. Harrison
- Invasive Insect Biocontrol and Behavior Laboratory, USDA Agricultural Research Service, Beltsville, MD 20705, USA
| | - Amy L. Toth
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
| | - W. Allen Miller
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011, USA
| | - Bryony C. Bonning
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
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