1
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Bodner L, Jasinska W, Bouchebti S, Scharf I, Brotman Y, Levin E. Metabolomics analysis of larval secretions reveals a caste-driven nutritional shift in a social wasp colony. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2024; 169:104128. [PMID: 38657707 DOI: 10.1016/j.ibmb.2024.104128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 04/21/2024] [Accepted: 04/21/2024] [Indexed: 04/26/2024]
Abstract
Social wasps exhibit a unique nutritional cycle in which adults feed larvae with prey, and larvae provide adults with larval secretions (LS). LS serves as a vital nutritional source for adults, contributing to the colony's health and reproductive success. The LS nutrient composition has been previously reported in various wasp species, yet these analyses focused solely on worker-destined larvae, overlooking the potential caste designation effects on LS composition. Using metabolomics techniques, we analysed and compared the metabolite and nutrient composition in LS of queen- and worker-destined larvae of the Oriental hornet. We found that queen-destined LS (QLS) contain greater amounts of most metabolites, including amino acids, and smaller amounts of sugars compared to worker-destined LS (WLS). The amino acid-to-sugar ratio in QLS was approximately tenfold higher than in WLS. Thus, as the colony transitions from the production of workers to the production of reproductives, it gradually experiences a nutritional shift that may influence the behaviour and physiology of the adult nest population. This caste-specific metabolite profile and nutrient composition of LS reflect the differences in the diet and physiological requirements of worker- and queen-destined larvae and may play a critical role in caste determination in social wasps.
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Affiliation(s)
- Levona Bodner
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel.
| | - Weronika Jasinska
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Sofia Bouchebti
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Inon Scharf
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Yariv Brotman
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Eran Levin
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
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2
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Lin S, Elsner D, Ams L, Korb J, Rosengaus R. A genetic toolkit underlying the queen phenotype in termites with totipotent workers. Sci Rep 2024; 14:2214. [PMID: 38278833 PMCID: PMC10817970 DOI: 10.1038/s41598-024-51772-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 01/09/2024] [Indexed: 01/28/2024] Open
Abstract
Social insect castes (e.g., queens, workers) are prime examples of phenotypic plasticity (i.e., different phenotypes arising from the same genotype). Yet, the mechanisms that give rise to highly fertile, long-lived queens versus non-reproducing, short-lived workers are not well understood. Recently, a module of co-expressed genes has been identified that characterizes queens compared to workers of the termite Cryptotermes secundus (Kalotermitidae): the Queen Central Module (QCM). We tested whether the QCM is shared in termite species, in which queens gradually develop via early larval and late larval instars, the latter functioning as totipotent workers (linear development). Similar as in C. secundus, gene expression profiles revealed an enrichment of QCM genes in Zootermopsis angusticollis queens, a species from another termite family (Archotermopsidae). The expression of these QCM genes became gradually enriched during development from early larval instars via workers to queens. Thus, our results support the hypothesis of a conserved genetic toolkit that characterizes termite queens with gradual linear development. Our data also imply a strong caste-specific tissue specificity with the QCM signal being restricted to head-prothorax tissues in termite queens. This tissue-specific expression of key aging-related genes might have facilitated the evolution of a long lifespan in termite queens.
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Affiliation(s)
- Silu Lin
- Evolutionary Biology and Ecology, University of Freiburg, 79104, Freiburg, Germany
| | - Daniel Elsner
- Evolutionary Biology and Ecology, University of Freiburg, 79104, Freiburg, Germany
| | - Leon Ams
- Evolutionary Biology and Ecology, University of Freiburg, 79104, Freiburg, Germany
| | - Judith Korb
- Evolutionary Biology and Ecology, University of Freiburg, 79104, Freiburg, Germany.
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina Campus, Darwin, NT, 0909, Australia.
| | - Rebeca Rosengaus
- Department of Marine and Environmental Sciences, Northeastern University, Boston, MA, 02115, USA.
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3
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Wynants E, Van Dun C, Lenaerts N, Princen SA, Tuyttens E, Shpigler HY, Wenseleers T, Van Oystaeyen A. Uncovering the role of juvenile hormone in ovary development and egg laying in bumble bees. JOURNAL OF INSECT PHYSIOLOGY 2023; 150:104557. [PMID: 37625783 DOI: 10.1016/j.jinsphys.2023.104557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/18/2023] [Accepted: 08/21/2023] [Indexed: 08/27/2023]
Abstract
Juvenile hormone (JH) regulates developmental and physiological processes in insects. In bumble bees, the hormone acts as a gonadotropin that mediates ovary development, but the exact physiological pathways involved in ovary activation and subsequent egg laying are poorly understood. In this study, we examine how queen hibernation state, caste, and species impact the gonadotropic effect of JH in bumble bee queens through methoprene (JH analogue) application. We extend previous research by assessing queen egg laying and colony initiation, alongside ovary development. Furthermore, we compared sensitivity of workers of both species to the juvenile hormone's gonadotropic effect. In both bumble bee species, the ovaries of hibernated queens were developed five to six days after breaking diapause, regardless of methoprene treatment. By contrast, methoprene did have a stimulatory effect on ovary development in non-hibernated queens. The dose needed to obtain this effect was higher in B. impatiens. Methoprene did not have gonadotropic effects in callow workers of both species. These results indicate that the physiological effect of exogenous methoprene application varies according to species, caste and hibernation status. Interestingly, despite gonadotropic effects in non-hibernated queens, oviposition was not accelerated by JH. This suggests that JH alone is insufficient to induce egg laying and that an additional stimulus, which is naturally present in hibernated queens, is required. Consequently, our findings indicate that other physiological processes, beyond a rise in JH alone, are required for oviposition and colony initiation.
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Affiliation(s)
- Enya Wynants
- Biobest Group NV, Research and Development, 2260 Westerlo, Belgium
| | - Cédric Van Dun
- Laboratory of Socio-ecology and Social Evolution, University of Leuven, 3000 Leuven, Belgium
| | - Nancy Lenaerts
- Biobest Group NV, Research and Development, 2260 Westerlo, Belgium
| | - Sarah A Princen
- Biobest Group NV, Research and Development, 2260 Westerlo, Belgium
| | - Ella Tuyttens
- Biobest Group NV, Research and Development, 2260 Westerlo, Belgium
| | - Hagai Y Shpigler
- Department of Entomology, Agricultural Research Organization, The Volcani Institute, Rishon LeZion, Israel
| | - Tom Wenseleers
- Laboratory of Socio-ecology and Social Evolution, University of Leuven, 3000 Leuven, Belgium
| | - Annette Van Oystaeyen
- Biobest Group NV, Research and Development, 2260 Westerlo, Belgium; Laboratory of Socio-ecology and Social Evolution, University of Leuven, 3000 Leuven, Belgium.
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4
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Lovegrove MR, Dearden PK, Duncan EJ. Honeybee queen mandibular pheromone induces a starvation response in Drosophila melanogaster. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2023; 154:103908. [PMID: 36657589 DOI: 10.1016/j.ibmb.2023.103908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 12/27/2022] [Accepted: 01/13/2023] [Indexed: 06/17/2023]
Abstract
Eusocial insect societies are defined by the reproductive division of labour, a social structure that is generally enforced by the reproductive dominant(s) or 'queen(s)'. Reproductive dominance is maintained through behavioural dominance or production of queen pheromones, or a mixture of both. Queen mandibular pheromone (QMP) is a queen pheromone produced by queen honeybees (Apis mellifera) which represses reproduction in worker honeybees. How QMP acts to repress worker reproduction, the mechanisms by which this repression is induced, and how it has evolved this activity, remain poorly understood. Surprisingly, QMP is capable of repressing reproduction in non-target arthropods. Here we show that in Drosophila melanogaster QMP treatment mimics the starvation response, disrupting reproduction. QMP exposure induces an increase in food consumption and activation of checkpoints in the ovary that reduce fecundity and depresses insulin signalling. The magnitude of these effects is indistinguishable between QMP-treated and starved individuals. As QMP triggers a starvation response in an insect diverged from honeybees, we propose that QMP originally evolved by co-opting nutrition signalling pathways to regulate reproduction.
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Affiliation(s)
- Mackenzie R Lovegrove
- Genomics Aotearoa and Biochemistry Department, University of Otago, P.O. Box 56, Dunedin, Aotearoa, New Zealand; School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Peter K Dearden
- Genomics Aotearoa and Biochemistry Department, University of Otago, P.O. Box 56, Dunedin, Aotearoa, New Zealand.
| | - Elizabeth J Duncan
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
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5
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Knapp RA, Norman VC, Rouse JL, Duncan EJ. Environmentally responsive reproduction: neuroendocrine signalling and the evolution of eusociality. CURRENT OPINION IN INSECT SCIENCE 2022; 53:100951. [PMID: 35863739 PMCID: PMC9586883 DOI: 10.1016/j.cois.2022.100951] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 07/06/2022] [Accepted: 07/11/2022] [Indexed: 05/12/2023]
Abstract
Eusociality is a rare but successful life-history strategy that is defined by the reproductive division of labour. In eusocial species, most females forgo their own reproduction to support that of a dominant female or queen. In many eusocial insects, worker reproduction is inhibited via dominance hierarchies or by pheromones produced by the queen and her brood. Here, we consider whether these cues may act as generic 'environmental signals', similar to temperature or nutrition stress, which induce a state of reproductive dormancy in some solitary insects. We review the recent findings regarding the mechanisms of reproductive dormancy in insects and highlight key gaps in our understanding of how environmental cues inhibit reproduction.
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Affiliation(s)
- Rosemary A Knapp
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Victoria C Norman
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - James L Rouse
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Elizabeth J Duncan
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
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6
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Saleh NW, Henske J, Ramírez SR. Experimental disruption of social structure reveals totipotency in the orchid bee, Euglossa dilemma. Evolution 2022; 76:1529-1545. [PMID: 35589274 DOI: 10.1111/evo.14513] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/29/2022] [Accepted: 04/07/2022] [Indexed: 01/22/2023]
Abstract
Eusociality has evolved multiple times across the insect phylogeny. Social insects with greater levels of social complexity tend to exhibit specialized castes with low levels of individual phenotypic plasticity. In contrast, species with simple social groups may consist of totipotent individuals that transition among behavioral and reproductive states. However, recent work has shown that in simple social groups, there can still be constraint on individual plasticity, caused by differences in maternal nourishment or social interaction. It is not well understood how these constraints arise, ultimately leading to the evolution of nonreproductive workers. Some species of orchid bees form social groups of a dominant and-one to two subordinate helpers where all individuals are reproductive. Females can also disperse to start their own nest as a solitary foundress, which includes a nonreproductive phase characterized by ovary inactivation, not typically expressed by subordinates. Little is known about individual flexibility across these trajectories. Here, using the orchid bee Euglossa dilemma, we assess the plasticity of subordinate helpers, finding that they are capable of the same behavioral, physiological, transcriptomic, and chemical changes seen in foundresses. Our results suggest that the lack of nonreproductive workers in E. dilemma is not due to a lack of subordinate plasticity.
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Affiliation(s)
- Nicholas W Saleh
- Entomology and Nematology Department, Fort Lauderdale Research and Education Center, University of Florida, Davie, Florida, USA.,Center for Population Biology, University of California, Davis, California, USA
| | - Jonas Henske
- Department of Animal Ecology, Evolution and Biodiversity, Ruhr University Bochum, Bochum, Germany
| | - Santiago R Ramírez
- Center for Population Biology, University of California, Davis, California, USA
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7
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Ferreira HM, da Silva RC, do Nascimento FS, Wenseleers T, Oi CA. Reproduction and fertility signalling under joint juvenile hormone control in primitively eusocial Mischocyttarus wasps. CHEMOECOLOGY 2022. [DOI: 10.1007/s00049-022-00370-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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8
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Saleh NW, Hodgson K, Pokorny T, Mullins A, Chouvenc T, Eltz T, Ramírez SR. Social Behavior, Ovary Size, and Population of Origin Influence Cuticular Hydrocarbons in the Orchid Bee Euglossa dilemma. Am Nat 2021; 198:E136-E151. [PMID: 34648396 DOI: 10.1086/716511] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractCuticular hydrocarbons (CHCs) are waxy compounds on the surface of insects that prevent desiccation and frequently serve as chemical signals mediating social and mating behaviors. Although their function in eusocial species has been heavily investigated, little is known about the evolution of CHC-based communication in species with simpler forms of social organization lacking specialized castes. Here we investigate factors shaping CHC variation in the orchid bee Euglossa dilemma, which forms casteless social groups of two to three individuals. We first assess geographic variation, examining CHC profiles of males and females from three populations. We also consider CHC variation in the sister species, Euglossa viridissima, which occurs sympatrically with one population of E. dilemma. Next, we consider variation associated with female behavioral phases, to test the hypothesis that CHCs reflect ovary size and social dominance. We uncover a striking CHC polymorphism in E. dilemma spanning populations. In addition, we identify a separate set of CHCs that correlate with ovary size, social dominance, and expression of genes associated with social behavior, suggesting that CHCs convey reproductive and social information in E. dilemma. Together, our results reveal complex patterns of variation in which a subset of CHCs reflect the social and reproductive status of nestmates.
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9
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Bebbington K, Groothuis TGG. Who listens to mother? A whole-family perspective on the evolution of maternal hormone allocation. Biol Rev Camb Philos Soc 2021; 96:1951-1968. [PMID: 33988906 PMCID: PMC8518390 DOI: 10.1111/brv.12733] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/30/2021] [Accepted: 05/04/2021] [Indexed: 12/14/2022]
Abstract
Maternal effects, or the influence of maternal environment and phenotype on offspring phenotype, may allow mothers to fine-tune their offspring's developmental trajectory and resulting phenotype sometimes long after the offspring has reached independence. However, maternal effects on offspring phenotype do not evolve in isolation, but rather within the context of a family unit, where the separate and often conflicting evolutionary interests of mothers, fathers and offspring are all at play. While intrafamilial conflicts are routinely invoked to explain other components of reproductive strategy, remarkably little is known about how intrafamilial conflicts influence maternal effects. We argue that much of the considerable variation in the relationship between maternally derived hormones, nutrients and other compounds and the resulting offspring phenotype might be explained by the presence of conflicting selection pressures on different family members. In this review, we examine the existing literature on maternal hormone allocation as a case study for maternal effects more broadly, and explore new hypotheses that arise when we consider current findings within a framework that explicitly incorporates the different evolutionary interests of the mother, her offspring and other family members. Specifically, we hypothesise that the relationship between maternal hormone allocation and offspring phenotype depends on a mother's ability to manipulate the signals she sends to offspring, the ability of family members to be plastic in their response to those signals and the capacity for the phenotypes and strategies of various family members to interact and influence one another on both behavioural and evolutionary timescales. We also provide suggestions for experimental, comparative and theoretical work that may be instrumental in testing these hypotheses. In particular, we highlight that manipulating the level of information available to different family members may reveal important insights into when and to what extent maternal hormones influence offspring development. We conclude that the evolution of maternal hormone allocation is likely to be shaped by the conflicting fitness optima of mothers, fathers and offspring, and that the outcome of this conflict depends on the relative balance of power between family members. Extending our hypotheses to incorporate interactions between family members, as well as more complex social groups and a wider range of taxa, may provide exciting new developments in the fields of endocrinology and maternal effects.
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Affiliation(s)
- Kat Bebbington
- Behavioural Biology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, Groningen, 9747AG, The Netherlands.,Animal Sciences, Wageningen University and Research, de Elst 1, Wageningen, 6708WD, The Netherlands
| | - Ton G G Groothuis
- Behavioural Biology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, Groningen, 9747AG, The Netherlands
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10
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Séguret A, Stolle E, Fleites-Ayil FA, Quezada-Euán JJG, Hartfelder K, Meusemann K, Harrison MC, Soro A, Paxton RJ. Transcriptomic Signatures of Ageing Vary in Solitary and Social Forms of an Orchid Bee. Genome Biol Evol 2021; 13:6259147. [PMID: 33914875 PMCID: PMC8214409 DOI: 10.1093/gbe/evab075] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/06/2021] [Indexed: 12/14/2022] Open
Abstract
Eusocial insect queens are remarkable in their ability to maximize both fecundity and longevity, thus escaping the typical trade-off between these two traits. Several mechanisms have been proposed to underlie the remolding of the trade-off, such as reshaping of the juvenile hormone (JH) pathway, or caste-specific susceptibility to oxidative stress. However, it remains a challenge to disentangle the molecular mechanisms underlying the remolding of the trade-off in eusocial insects from caste-specific physiological attributes that have subsequently arisen. The socially polymorphic orchid bee Euglossa viridissima represents an excellent model to address the role of sociality per se in longevity as it allows direct comparisons of solitary and social individuals within a common genetic background. We investigated gene expression and JH levels in young and old bees from both solitary and social nests. We found 902 genes to be differentially expressed with age in solitary females, including genes involved in oxidative stress, versus only 100 genes in social dominant females, and 13 genes in subordinate females. A weighted gene coexpression network analysis further highlights pathways related to ageing in this species, including the target of rapamycin pathway. Eleven genes involved in translation, apoptosis, and DNA repair show concurrent age-related expression changes in solitary but not in social females, representing potential differences based on social status. JH titers did not vary with age or social status. Our results represent an important step in understanding the proximate mechanisms underlying the remodeling of the fecundity/longevity trade-off that accompanies the evolutionary transition from solitary life to eusociality.
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Affiliation(s)
- Alice Séguret
- Institute of Biology, Martin-Luther-University Halle-Wittenberg, Halle, Germany.,Institute for Evolution and Biodiversity, Westfälische-Wilhelms University, Münster, Germany
| | - Eckart Stolle
- Institute of Biology, Martin-Luther-University Halle-Wittenberg, Halle, Germany.,Leibniz Institute of Animal Biodiversity, Zoological Research Museum Alexander Koenig, Center of Molecular Biodiversity Research, Bonn, Germany
| | | | - José Javier G Quezada-Euán
- Department of Apiculture, Campus of Biological Sciences and Animal Husbandry, Autonomous University of Yucatán, Mérida, Mexico
| | - Klaus Hartfelder
- Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, Brazil
| | - Karen Meusemann
- Evolutionary Biology and Ecology, Albert-Ludwigs-University Freiburg, Freiburg (i. Brsg.), Germany
| | - Mark C Harrison
- Institute for Evolution and Biodiversity, Westfälische-Wilhelms University, Münster, Germany
| | - Antonella Soro
- Institute of Biology, Martin-Luther-University Halle-Wittenberg, Halle, Germany
| | - Robert J Paxton
- Institute of Biology, Martin-Luther-University Halle-Wittenberg, Halle, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
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11
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Ostwald MM, Fox TP, Harrison JF, Fewell JH. Social consequences of energetically costly nest construction in a facultatively social bee. Proc Biol Sci 2021; 288:20210033. [PMID: 33906404 PMCID: PMC8080015 DOI: 10.1098/rspb.2021.0033] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 03/26/2021] [Indexed: 01/13/2023] Open
Abstract
Social groups form when the costs of breeding independently exceed fitness costs imposed by group living. The costs of independent breeding can often be energetic, especially for animals performing expensive behaviours, such as nest construction. To test the hypothesis that nesting costs can drive sociality by disincentivizing independent nest founding, we measured the energetics of nest construction and inheritance in a facultatively social carpenter bee (Xylocopa sonorina Smith), which bores tunnel nests in wood. We measured metabolic rates of bees excavating wood and used computerized tomography images of nesting logs to measure excavation volumes. From these data, we demonstrate costly energetic investments in nest excavation of a minimum 4.3 kJ per offspring provisioned, an expense equivalent to nearly 7 h of flight. This high, potentially prohibitive cost of nest founding may explain why females compete for existing nests rather than constructing new ones, often leading to the formation of social groups. Further, we found that nest inheritors varied considerably in their investment in nest renovation, with costs ranging more than 12-fold (from 7.08 to 89.1 kJ energy), probably reflecting differences in inherited nest quality. On average, renovation costs were lower than estimated new nest construction costs, with some nests providing major savings. These results suggest that females may join social groups to avoid steep energetic costs, but that the benefits of this strategy are not experienced equally.
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Affiliation(s)
| | - Trevor P. Fox
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Jon F. Harrison
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
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12
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Hagadorn MA, Johnson MM, Smith AR, Seid MA, Kapheim KM. Experience, but not age, is associated with volumetric mushroom body expansion in solitary alkali bees. J Exp Biol 2021; 224:jeb.238899. [DOI: 10.1242/jeb.238899] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 02/09/2021] [Indexed: 01/03/2023]
Abstract
ABSTRACT
In social insects, changes in behavior are often accompanied by structural changes in the brain. This neuroplasticity may come with experience (experience-dependent) or age (experience-expectant). Yet, the evolutionary relationship between neuroplasticity and sociality is unclear, because we know little about neuroplasticity in the solitary relatives of social species. We used confocal microscopy to measure brain changes in response to age and experience in a solitary halictid bee (Nomia melanderi). First, we compared the volume of individual brain regions among newly emerged females, laboratory females deprived of reproductive and foraging experience, and free-flying, nesting females. Experience, but not age, led to significant expansion of the mushroom bodies – higher-order processing centers associated with learning and memory. Next, we investigated how social experience influences neuroplasticity by comparing the brains of females kept in the laboratory either alone or paired with another female. Paired females had significantly larger olfactory regions of the mushroom bodies. Together, these experimental results indicate that experience-dependent neuroplasticity is common to both solitary and social taxa, whereas experience-expectant neuroplasticity may be an adaptation to life in a social colony. Further, neuroplasticity in response to social chemical signals may have facilitated the evolution of sociality.
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Affiliation(s)
- Mallory A. Hagadorn
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322, USA
| | - Makenna M. Johnson
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322, USA
| | - Adam R. Smith
- Department of Biological Sciences, George Washington University, 800 22nd St NW, Washington, DC 20052, USA
| | - Marc A. Seid
- Biology Department, University of Scranton, 800 Linden St, Scranton, PA 18510, USA
| | - Karen M. Kapheim
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322, USA
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13
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Lin S, Werle J, Korb J. Transcriptomic analyses of the termite, Cryptotermes secundus, reveal a gene network underlying a long lifespan and high fecundity. Commun Biol 2021; 4:384. [PMID: 33753888 PMCID: PMC7985136 DOI: 10.1038/s42003-021-01892-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 02/19/2021] [Indexed: 01/31/2023] Open
Abstract
Organisms are typically characterized by a trade-off between fecundity and longevity. Notable exceptions are social insects. In insect colonies, the reproducing caste (queens) outlive their non-reproducing nestmate workers by orders of magnitude and realize fecundities and lifespans unparalleled among insects. How this is achieved is not understood. Here, we identified a single module of co-expressed genes that characterized queens in the termite species Cryptotermes secundus. It encompassed genes from all essential pathways known to be involved in life-history regulation in solitary model organisms. By manipulating its endocrine component, we tested the recent hypothesis that re-wiring along the nutrient-sensing/endocrine/fecundity axis can account for the reversal of the fecundity/longevity trade-off in social insect queens. Our data from termites do not support this hypothesis. However, they revealed striking links to social communication that offer new avenues to understand the re-modelling of the fecundity/longevity trade-off in social insects.
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Affiliation(s)
- Silu Lin
- grid.5963.9Evolutionary Biology and Ecology, University of Freiburg, Freiburg, Germany
| | - Jana Werle
- grid.5963.9Evolutionary Biology and Ecology, University of Freiburg, Freiburg, Germany
| | - Judith Korb
- grid.5963.9Evolutionary Biology and Ecology, University of Freiburg, Freiburg, Germany
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14
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Ge J, Ge Z, Zhu D, Wang X. Pheromonal Regulation of the Reproductive Division of Labor in Social Insects. Front Cell Dev Biol 2020; 8:837. [PMID: 32974354 PMCID: PMC7468439 DOI: 10.3389/fcell.2020.00837] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 08/05/2020] [Indexed: 11/13/2022] Open
Abstract
The reproductive altruism in social insects is an evolutionary enigma that has been puzzling scientists starting from Darwin. Unraveling how reproductive skew emerges and maintains is crucial to understand the reproductive altruism involved in the consequent division of labor. The regulation of adult worker reproduction involves conspecific inhibitory signals, which are thought to be chemical signals by numerous studies. Despite the primary identification of few chemical ligands, the action modes of primer pheromones that regulate reproduction and their molecular causes and effects remain challenging. Here, these questions were elucidated by comprehensively reviewing recent advances. The coordination with other modalities of queen pheromones (QPs) and its context-dependent manner to suppress worker reproduction were discussed under the vast variation and plasticity of reproduction during colony development and across taxa. In addition to the effect of QPs, special attention was paid to recent studies revealing the regulatory effect of brood pheromones. Considering the correlation between pheromone and hormone, this study focused on the production and perception of pheromones under the endocrine control and highlighted the pivotal roles of nutrition-related pathways. The novel chemicals and gene pathways discovered by recent works provide new insights into the understanding of social regulation of reproductive division of labor in insects.
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Affiliation(s)
- Jin Ge
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Zhuxi Ge
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Dan Zhu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Xianhui Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
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Müller C, Caspers BA, Gadau J, Kaiser S. The Power of Infochemicals in Mediating Individualized Niches. Trends Ecol Evol 2020; 35:981-989. [PMID: 32723498 DOI: 10.1016/j.tree.2020.07.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/26/2020] [Accepted: 07/02/2020] [Indexed: 12/24/2022]
Abstract
Infochemicals, including hormones, pheromones, and allelochemicals, play a central role in mediating information and shaping interactions within and between individuals. Due to their high plasticity, infochemicals are predestined mediators in facilitating individualized niches of organisms. Only recently it has become clear that individual differences are essential to understand how and why individuals realize a tiny subset of the species' niche. Moreover, individual differences have a central role in both ecological adjustment and evolutionary adaptation in a rapidly changing world. Here we highlight that infochemicals act as key signals or cues and empower the realization of the individualized niche through three proposed processes: niche choice, niche conformance, and niche construction.
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Affiliation(s)
- Caroline Müller
- Chemical Ecology, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany.
| | - Barbara A Caspers
- Behavioral Ecology, Bielefeld University, Konsequenz 45, 33615 Bielefeld, Germany
| | - Jürgen Gadau
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstraße 1, 48149 Münster, Germany
| | - Sylvia Kaiser
- Department of Behavioural Biology, University of Münster, Badestr. 13, 48149 Münster, Germany
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16
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Pahlke S, Jaumann S, Seid MA, Smith AR. Brain differences between social castes precede group formation in a primitively eusocial bee. Naturwissenschaften 2019; 106:49. [DOI: 10.1007/s00114-019-1644-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/20/2019] [Accepted: 08/05/2019] [Indexed: 02/03/2023]
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17
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Saleh NW, Ramírez SR. Sociality emerges from solitary behaviours and reproductive plasticity in the orchid bee Euglossa dilemma. Proc Biol Sci 2019; 286:20190588. [PMID: 31288697 DOI: 10.1098/rspb.2019.0588] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The evolution of eusociality and sterile worker castes represents a major transition in the history of life. Despite this, little is known about the mechanisms involved in the initial transition from solitary to social behaviour. It has been hypothesized that plasticity from ancestral solitary life cycles was coopted to create queen and worker castes in insect societies. Here, we tested this hypothesis by examining gene expression involved in the transition from solitary to social behaviour in the orchid bee Euglossa dilemma. To this end, we conducted observations that allowed us to classify bees into four distinct categories of solitary and social behaviour. Then, by sequencing brain and ovary transcriptomes from these behavioural phases, we identified gene expression changes overlapping with socially associated genes across multiple eusocial lineages. We find that genes involved in solitary E. dilemma ovarian plasticity overlap extensively with genes showing differential expression between fertile and sterile workers-or between queens and workers in other eusocial bees. We also find evidence that sociality in E. dilemma reflects gene expression patterns involved in solitary foraging and non-foraging nest care behaviours. Our results provide strong support for the hypothesis that eusociality emerges from plasticity found across solitary life cycles.
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Affiliation(s)
- Nicholas W Saleh
- Center for Population Biology, University of California , Davis, CA , USA
| | - Santiago R Ramírez
- Center for Population Biology, University of California , Davis, CA , USA
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18
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Jaumann S, Seid MA, Simons M, Smith AR. Queen Dominance May Reduce Worker Mushroom Body Size in a Social Bee. Dev Neurobiol 2019; 79:596-607. [PMID: 31207130 DOI: 10.1002/dneu.22705] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 06/10/2019] [Accepted: 06/11/2019] [Indexed: 01/20/2023]
Abstract
The mushroom body (MB) is an area of the insect brain involved in learning, memory, and sensory integration. Here, we used the sweat bee Megalopta genalis (Halictidae) to test for differences between queens and workers in the volume of the MB calyces. We used confocal microscopy to measure the volume of the whole brain, MB calyces, optic lobes, and antennal lobes of queens and workers. Queens had larger brains, larger MB calyces, and a larger MB calyces:whole brain ratio than workers, suggesting an effect of social dominance in brain development. This could result from social interactions leading to smaller worker MBs, or larger queen MBs. It could also result from other factors, such as differences in age or sensory experience. To test these explanations, we next compared queens and workers to other groups. We compared newly emerged bees, bees reared in isolation for 10 days, bees initiating new observation nests, and bees initiating new natural nests collected from the field to queens and workers. Queens did not differ from these other groups. We suggest that the effects of queen dominance over workers, rather than differences in age, experience, or reproductive status, are responsible for the queen-worker differences we observed. Worker MB development may be affected by queen aggression directly and/or manipulation of larval nutrition, which is provisioned by the queen. We found no consistent differences in the size of antennal lobes or optic lobes associated with differences in age, experience, reproductive status, or social caste.
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Affiliation(s)
- Sarah Jaumann
- Department of Biological Sciences, George Washington University, Washington, District of Columbia
| | - Marc A Seid
- Biology Department, University of Scranton, Scranton, Pennsylvania
| | - Meagan Simons
- Department of Biological Sciences, George Washington University, Washington, District of Columbia
| | - Adam R Smith
- Department of Biological Sciences, George Washington University, Washington, District of Columbia
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Kapheim KM, Pan H, Li C, Blatti C, Harpur BA, Ioannidis P, Jones BM, Kent CF, Ruzzante L, Sloofman L, Stolle E, Waterhouse RM, Zayed A, Zhang G, Wcislo WT. Draft Genome Assembly and Population Genetics of an Agricultural Pollinator, the Solitary Alkali Bee (Halictidae: Nomia melanderi). G3 (BETHESDA, MD.) 2019; 9:625-634. [PMID: 30642875 PMCID: PMC6404593 DOI: 10.1534/g3.118.200865] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 01/12/2019] [Indexed: 02/07/2023]
Abstract
Alkali bees (Nomia melanderi) are solitary relatives of the halictine bees, which have become an important model for the evolution of social behavior, but for which few solitary comparisons exist. These ground-nesting bees defend their developing offspring against pathogens and predators, and thus exhibit some of the key traits that preceded insect sociality. Alkali bees are also efficient native pollinators of alfalfa seed, which is a crop of major economic value in the United States. We sequenced, assembled, and annotated a high-quality draft genome of 299.6 Mbp for this species. Repetitive content makes up more than one-third of this genome, and previously uncharacterized transposable elements are the most abundant type of repetitive DNA. We predicted 10,847 protein coding genes, and identify 479 of these undergoing positive directional selection with the use of population genetic analysis based on low-coverage whole genome sequencing of 19 individuals. We found evidence of recent population bottlenecks, but no significant evidence of population structure. We also identify 45 genes enriched for protein translation and folding, transcriptional regulation, and triglyceride metabolism evolving slower in alkali bees compared to other halictid bees. These resources will be useful for future studies of bee comparative genomics and pollinator health research.
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Affiliation(s)
- Karen M Kapheim
- Department of Biology, Utah State University, Logan, UT 84322
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama
| | - Hailin Pan
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, China
- China National Genebank, BGI-Shenzhen, 518083, Shenzhen, Guangdong, China
- Centre for Social Evolution, Department of Biology, Universitetsparken 15, University of Copenhagen, DK-2100, Copenhagen, Denmark
| | - Cai Li
- The Francis Crick Institute, London NW1 1AT, United Kingdom
| | - Charles Blatti
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL
| | - Brock A Harpur
- Department of Entomology, Purdue University, W. Lafayette, IN, 47907
| | - Panagiotis Ioannidis
- Foundation for Research and Technology Hellas, Institute of Molecular Biology and Biotechnology, 70013 Vassilika Vouton, Heraklion, Greece
| | - Beryl M Jones
- Program in Ecology, Evolution, and Conservation Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Clement F Kent
- Department of Biology, York University, Toronto, Ontario, M3J 1P3, Canada
| | - Livio Ruzzante
- Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland
| | - Laura Sloofman
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL
| | - Eckart Stolle
- Institute of Biology, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany
| | - Robert M Waterhouse
- Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland
| | - Amro Zayed
- Department of Biology, York University, Toronto, Ontario, M3J 1P3, Canada
| | - Guojie Zhang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, China
- China National Genebank, BGI-Shenzhen, 518083, Shenzhen, Guangdong, China
- Centre for Social Evolution, Department of Biology, Universitetsparken 15, University of Copenhagen, DK-2100, Copenhagen, Denmark
| | - William T Wcislo
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama
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21
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Taylor D, Bentley MA, Sumner S. Social wasps as models to study the major evolutionary transition to superorganismality. CURRENT OPINION IN INSECT SCIENCE 2018; 28:26-32. [PMID: 30551764 DOI: 10.1016/j.cois.2018.04.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 04/03/2018] [Accepted: 04/05/2018] [Indexed: 06/09/2023]
Abstract
The major evolutionary transition to superorganismality has taken place several times in the insects. Although there has been much consideration of the ultimate evolutionary explanations for superorganismality, we know relatively little about what proximate mechanisms constrain or promote this major transition. Here, we propose that Vespid wasps represent an understudied, but potentially very useful, model system for studying the mechanisms underpinning superorganismality. We highlight how there is an abundance of behavioural data for many wasp species, confirming their utility in studies of social evolution; however, there is a sparsity of genomic data from which we can test proximate and ultimate hypotheses on this major evolutionary transition.
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Affiliation(s)
- Daisy Taylor
- Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, United Kingdom
| | - Michael A Bentley
- Centre for Biodiversity & Environment Research, Department of Genetics, Evolution & Environment, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Seirian Sumner
- Centre for Biodiversity & Environment Research, Department of Genetics, Evolution & Environment, University College London, Gower Street, London WC1E 6BT, United Kingdom.
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22
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Dani FR, Turillazzi S. Chemical Communication and Reproduction Partitioning in Social Wasps. J Chem Ecol 2018; 44:796-804. [DOI: 10.1007/s10886-018-0968-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 04/01/2018] [Accepted: 05/06/2018] [Indexed: 12/13/2022]
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23
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Kapheim KM, Johnson MM. Juvenile hormone, but not nutrition or social cues, affects reproductive maturation in solitary alkali bees ( Nomia melanderi). ACTA ACUST UNITED AC 2017; 220:3794-3801. [PMID: 28821570 DOI: 10.1242/jeb.162255] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 08/15/2017] [Indexed: 12/12/2022]
Abstract
Eusocial insect colonies are defined by extreme variation in reproductive activity among castes, but the ancestral conditions from which this variation arose are unknown. Investigating the factors that contribute to variation in reproductive physiology among solitary insects that are closely related to social species can help to fill this gap. We experimentally tested the role of nutrition, juvenile hormone (JH) and social cues on reproductive maturation in solitary alkali bees (Halictidae: Nomia melanderi). We found that alkali bee females emerge from overwintering with small Dufour's glands and small ovaries, containing oocytes in the early stages of development. Oocyte maturation occurs rapidly, and is staggered between the two ovaries. Lab-reared females reached reproductive maturity without access to mates or nesting opportunities, and many had resorbed oocytes. Initial activation of these reproductive structures does not depend on pollen consumption, though dietary protein or lipids may be necessary for long-term reproductive activity. JH is likely to be a limiting factor in alkali bee reproductive activation, as females treated with JH were more likely to develop mature oocytes and Dufour's glands. Unlike for related social bees, the effects of JH were not suppressed by the presence of older, reproductive females. These results provide valuable insight into the factors that influence reproductive activity in an important native pollinator, and those that may have been particularly influential in the evolution of reproductive castes.
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Affiliation(s)
- Karen M Kapheim
- Utah State University, Department of Biology, 5305 Old Main Hill, Logan, UT 84322, USA
| | - Makenna M Johnson
- Utah State University, Department of Biology, 5305 Old Main Hill, Logan, UT 84322, USA
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