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Opachaloemphan C, Carmona-Aldana F, Yan H. Caste Transition and Reversion in Harpegnathos saltator Ant Colonies. Bio Protoc 2023; 13:e4770. [PMID: 37638295 PMCID: PMC10450750 DOI: 10.21769/bioprotoc.4770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 04/11/2023] [Accepted: 06/04/2023] [Indexed: 08/29/2023] Open
Abstract
Living organisms possess the ability to respond to environmental cues and adapt their behaviors and physiologies for survival. Eusocial insects, such as ants, bees, wasps, and termites, have evolved advanced sociality: living together in colonies where individuals innately develop into reproductive and non-reproductive castes. These castes exhibit remarkably distinct behaviors and physiologies that support their specialized roles in the colony. Among ant species, Harpegnathos saltator females stand out with their highly plastic caste phenotypes that can be easily manipulated in a laboratory environment. In this protocol, we provide detailed instructions on how to generate H. saltator ant colonies, define castes based on behavioral and physiological phenotypes, and experimentally induce caste switches, including the transition from a non-reproductive worker to a reproductive gamergate and vice versa (known as reversion). The unusual features of H. saltator make it a valuable tool to investigate cellular and molecular mechanisms underlying phenotypic plasticity in eusocial organisms. Key features H. saltator is one of few ant species showing remarkable caste plasticity with striking phenotypic changes, being a useful subject for studying behavioral plasticity. Caste switches in H. saltator can be easily manipulated in a controlled laboratory environment by controlling the presence of reproductive females in a colony. The relatively large size of H. saltator females allows researchers to dissect various tissues of interest and conduct detailed phenotypic analyses.
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Affiliation(s)
- Comzit Opachaloemphan
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, NY, USA
| | - Francisco Carmona-Aldana
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, NY, USA
| | - Hua Yan
- Department of Biology, University of Florida, Gainesville, FL, USA
- Center for Smell and Taste, University of Florida, Gainesville, FL, USA
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2
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Jeanne RL, Loope KJ, Bouwma AM, Nordheim EV, Smith ML. Five decades of misunderstanding in the social Hymenoptera: a review and meta-analysis of Michener's paradox. Biol Rev Camb Philos Soc 2022; 97:1559-1611. [PMID: 35338566 PMCID: PMC9546470 DOI: 10.1111/brv.12854] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 12/22/2022]
Abstract
In a much-cited 1964 paper entitled "Reproductive efficiency in relation to colony size in hymenopterous societies," Charles Michener investigated the correlation between a colony's size and its reproductive efficiency - the ability of its adult females to produce reproductives, measured as per-capita output. Based on his analysis of published data from destructively sampled colonies in 18 species, he reported that in most of these species efficiency decreased with increasing colony size. His conclusion that efficiency is higher in smaller groups has since gained widespread acceptance. But it created a seeming paradox: how can natural selection maintain social behaviour when a female apparently enjoys her highest per-capita output by working alone? Here we treat Michener's pattern as a hypothesis and perform the first large-scale test of its prediction across the eusocial Hymenoptera. Because data on actual output of reproductives were not available for most species, Michener used various proxies, such as nest size, numbers of brood, or amounts of stored food. We show that for each of Michener's data sets the reported decline in per-capita productivity can be explained by factors other than decreasing efficiency, calling into question his conclusion that declining efficiency is the cause of the pattern. The most prominent cause of bias is the failure of the proxy to capture all forms of output in which the colony invests during the course of its ontogeny. Other biasing factors include seasonal effects and a variety of methodological flaws in the data sets he used. We then summarize the results of 215 data sets drawn from post-1964 studies of 80 species in 33 genera that better control for these factors. Of these, 163 data sets are included in two meta-analyses that statistically synthesize the available data on the relationship between colony size and efficiency, accounting for variable sample sizes and non-independence among the data sets. The overall effect, and those for most taxonomic subgroups, indicates no loss of efficiency with increasing colony size. Two exceptional taxa, the halictid bees and independent-founding paper wasps, show negative trends consistent with the Michener hypothesis in some species. We conclude that in most species, particularly those with large colony sizes, the hypothesis of decreasing efficiency with increasing colony size is not supported. Finally, we explore potential mechanisms through which the level of efficiency can decrease, be maintained, or even increase, as colonies increase in size.
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Affiliation(s)
- Robert L Jeanne
- Department of Entomology, University of Wisconsin, 1630 Linden Drive, Madison, WI, 53706, U.S.A
| | - Kevin J Loope
- Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University (Virginia Tech), Cheatham Hall, 310 W. Campus Drive, Blacksburg, VA, 24060, U.S.A
| | - Andrew M Bouwma
- Department of Integrative Biology, Oregon State University, Cordley Hall, 3029, 2701 SW Campus Way, Corvallis, OR, 97331, U.S.A
| | - Erik V Nordheim
- Department of Statistics, University of Wisconsin, 1300 University Avenue, Madison, WI, 53706, U.S.A
| | - Michael L Smith
- Department of Biological Sciences, Auburn University, Auburn, AL, 36849, U.S.A
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3
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Hagadorn MA, Eck K, Del Grosso M, Haemmerle X, Wcislo WT, Kapheim KM. Age-related mushroom body expansion in male sweat bees and bumble bees. Sci Rep 2021; 11:17039. [PMID: 34426595 PMCID: PMC8382693 DOI: 10.1038/s41598-021-96268-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 08/04/2021] [Indexed: 01/20/2023] Open
Abstract
A well-documented phenomenon among social insects is that brain changes occur prior to or at the onset of certain experiences, potentially serving to prime the brain for specific tasks. This insight comes almost exclusively from studies considering developmental maturation in females. As a result, it is unclear whether age-related brain plasticity is consistent across sexes, and to what extent developmental patterns differ. Using confocal microscopy and volumetric analyses, we investigated age-related brain changes coinciding with sexual maturation in the males of the facultatively eusocial sweat bee, Megalopta genalis, and the obligately eusocial bumble bee, Bombus impatiens. We compared volumetric measurements between newly eclosed and reproductively mature males kept isolated in the lab. We found expansion of the mushroom bodies-brain regions associated with learning and memory-with maturation, which were consistent across both species. This age-related plasticity may, therefore, play a functionally-relevant role in preparing male bees for mating, and suggests that developmentally-driven neural restructuring can occur in males, even in species where it is absent in females.
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Affiliation(s)
- Mallory A Hagadorn
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT, 84322, USA.
| | - Karlee Eck
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT, 84322, USA
| | - Matthew Del Grosso
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT, 84322, USA
| | - Xavier Haemmerle
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT, 84322, USA
| | - William T Wcislo
- Smithsonian Tropical Research Institute, 0843-03092, Panama City, Republic of Panama
| | - Karen M Kapheim
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT, 84322, USA.
- Smithsonian Tropical Research Institute, 0843-03092, Panama City, Republic of Panama.
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4
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Kingwell C, Böröczky K, Steitz I, Ayasse M, Wcislo W. Cuticular and Dufour's Gland Chemistry Reflect Reproductive and Social State in the Facultatively Eusocial Sweat Bee Megalopta genalis (Hymenoptera: Halictidae). J Chem Ecol 2021; 47:420-432. [PMID: 33682070 DOI: 10.1007/s10886-021-01262-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/23/2021] [Accepted: 03/02/2021] [Indexed: 01/18/2023]
Abstract
Queen pheromones evolved independently in multiple eusocial insect lineages, in which they mediate reproductive conflict by inhibiting worker ovarian development. Although fundamentally important for reproductive division of labor - the hallmark of eusociality - their evolutionary origins are enigmatic. Here, we analyze cuticular and Dufour's gland chemistries across alternative social and reproductive phenotypes in Megalopta genalis bees (tribe Augochlorini, family Halictidae) that facultatively express simple eusociality. Reproductive bees have distinct overall glandular and cuticular chemical phenotypes compared with non-reproductive workers. On the cuticle, a likely site of signal transmission, reproductives are enriched for certain alkenes, most linear alkanes, and are heavily enriched for all methyl-branched alkanes. Chemicals belonging to these compound classes are known to function as fertility signals in other eusocial insect taxa. Some macrocyclic lactones, compounds that serve as queen pheromones in the other eusocial halictid tribe (Halictini), are also enriched among reproductives relative to workers. The intra-population facultative eusociality of M. genalis permits direct comparisons between individuals expressing alternative reproductive phenotypes - females that reproduce alone (solitary reproductives) and social queens - to highlight traits in the latter that may be important mediators of eusociality. Compared with solitary reproductives, the cuticular chemistries of queens are more strongly differentiated from those of workers, and furthermore are especially enriched for methyl-branched alkanes. Determining the pheromonal function(s) and information content of the candidate signaling compounds we identify will help illuminate the early evolutionary history of queen pheromones, chemical signals central to the organization of insect eusocial behavior.
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Affiliation(s)
- Callum Kingwell
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, USA.
- Smithsonian Tropical Research Institute, Panama City, Panama.
| | - Katalin Böröczky
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, USA
| | - Iris Steitz
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm, Germany
| | - Manfred Ayasse
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm, Germany
| | - William Wcislo
- Smithsonian Tropical Research Institute, Panama City, Panama
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5
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Developmental plasticity shapes social traits and selection in a facultatively eusocial bee. Proc Natl Acad Sci U S A 2020; 117:13615-13625. [PMID: 32471944 PMCID: PMC7306772 DOI: 10.1073/pnas.2000344117] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Developmental processes are an important source of phenotypic variation, but the extent to which this variation contributes to evolutionary change is unknown. We used integrative genomic analyses to explore the relationship between developmental and social plasticity in a bee species that can adopt either a social or solitary lifestyle. We find genes regulating this social flexibility also regulate development, and positive selection on these genes is influenced by their function during development. This suggests that developmental plasticity may influence the evolution of sociality. Our additional finding of genetic variants linked to differences in social behavior sheds light on how phenotypic variation derived from development may become encoded into the genome, and thus contribute to evolutionary change. Developmental plasticity generates phenotypic variation, but how it contributes to evolutionary change is unclear. Phenotypes of individuals in caste-based (eusocial) societies are particularly sensitive to developmental processes, and the evolutionary origins of eusociality may be rooted in developmental plasticity of ancestral forms. We used an integrative genomics approach to evaluate the relationships among developmental plasticity, molecular evolution, and social behavior in a bee species (Megalopta genalis) that expresses flexible sociality, and thus provides a window into the factors that may have been important at the evolutionary origins of eusociality. We find that differences in social behavior are derived from genes that also regulate sex differentiation and metamorphosis. Positive selection on social traits is influenced by the function of these genes in development. We further identify evidence that social polyphenisms may become encoded in the genome via genetic changes in regulatory regions, specifically in transcription factor binding sites. Taken together, our results provide evidence that developmental plasticity provides the substrate for evolutionary novelty and shapes the selective landscape for molecular evolution in a major evolutionary innovation: Eusociality.
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6
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Smith AR, Kapheim KM, Kingwell CJ, Wcislo WT. A split sex ratio in solitary and social nests of a facultatively social bee. Biol Lett 2019; 15:20180740. [PMID: 30940017 DOI: 10.1098/rsbl.2018.0740] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A classic prediction of kin selection theory is that a mixed population of social and solitary nests of haplodiploid insects should exhibit a split sex ratio among offspring: female biased in social nests, male biased in solitary nests. Here, we provide the first evidence of a solitary-social split sex ratio, using the sweat bee Megalopta genalis (Halictidae). Data from 2502 offspring collected from naturally occurring nests across 6 years spanning the range of the M. genalis reproductive season show that despite significant yearly and seasonal variation, the offspring sex ratio of social nests is consistently more female biased than in solitary nests. This suggests that split sex ratios may facilitate the evolutionary origins of cooperation based on reproductive altruism via kin selection.
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Affiliation(s)
- Adam R Smith
- 1 Department of Biological Sciences, George Washington University , Washington, DC , USA
| | - Karen M Kapheim
- 2 Department of Biology, Utah State University , Logan, UT , USA.,4 Smithsonian Tropical Research Institute , Panama City , Panama
| | - Callum J Kingwell
- 3 Department of Neurobiology and Behavior, Cornell University , Ithaca, NY , USA.,4 Smithsonian Tropical Research Institute , Panama City , Panama
| | - William T Wcislo
- 4 Smithsonian Tropical Research Institute , Panama City , Panama
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7
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Quiñones AE, Henriques GJB, Pen I. Queen–worker conflict can drive the evolution of social polymorphism and split sex ratios in facultatively eusocial life cycles*. Evolution 2019; 74:15-28. [DOI: 10.1111/evo.13844] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 08/26/2019] [Accepted: 09/02/2019] [Indexed: 11/28/2022]
Affiliation(s)
- Andrés E. Quiñones
- Theoretical Research in Evolutionary Life Sciences, Groningen Institute for Evolutionary Life SciencesUniversity of Groningen 9747 AG Groningen The Netherlands
- Laboratorio de Biología Evolutiva de Vertebrados, Departamento de Ciencias BiológicasUniversidad de los Andes Bogotá Colombia
| | - Gil J. B. Henriques
- Theoretical Research in Evolutionary Life Sciences, Groningen Institute for Evolutionary Life SciencesUniversity of Groningen 9747 AG Groningen The Netherlands
- Department of Zoology and Biodiversity Research CentreUniversity of British Columbia Vancouver British Columbia V6T 1Z4 Canada
| | - Ido Pen
- Theoretical Research in Evolutionary Life Sciences, Groningen Institute for Evolutionary Life SciencesUniversity of Groningen 9747 AG Groningen The Netherlands
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8
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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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9
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10
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Branstetter MG, Childers AK, Cox-Foster D, Hopper KR, Kapheim KM, Toth AL, Worley KC. Genomes of the Hymenoptera. CURRENT OPINION IN INSECT SCIENCE 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] [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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11
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Kapheim KM. Nutritional, endocrine, and social influences on reproductive physiology at the origins of social behavior. CURRENT OPINION IN INSECT SCIENCE 2017; 22:62-70. [PMID: 28805640 DOI: 10.1016/j.cois.2017.05.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 05/19/2017] [Accepted: 05/30/2017] [Indexed: 06/07/2023]
Abstract
Understanding the evolutionary origins of social behavior in insects requires understanding the physiological basis for reproductive plasticity. Solitary bees and wasps or those living in small, flexible societies will be key to understanding how conserved pathways have evolved to give rise to reproductive castes. Nutrient-sensing and endocrine pathways are decoupled from reproduction in some life stages of social insects. Heterochrony, particularly as it is related to diapause physiology, may be an important mechanism by which this decoupling occurs. Additional research is needed to understand how these pathways became sensitive to cues from the social environment. Future research targeting species with a diversity of social behaviors and diapause strategies will be key to understanding the physiological basis of social evolution.
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Affiliation(s)
- Karen M Kapheim
- Utah State University, Department of Biology, 5305 Old Main Hill, Logan, UT 84322, USA.
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12
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Jones BM, Kingwell CJ, Wcislo WT, Robinson GE. Caste-biased gene expression in a facultatively eusocial bee suggests a role for genetic accommodation in the evolution of eusociality. Proc Biol Sci 2017; 284:20162228. [PMID: 28053060 PMCID: PMC5247497 DOI: 10.1098/rspb.2016.2228] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 12/05/2016] [Indexed: 12/18/2022] Open
Abstract
Developmental plasticity may accelerate the evolution of phenotypic novelty through genetic accommodation, but studies of genetic accommodation often lack knowledge of the ancestral state to place selected traits in an evolutionary context. A promising approach for assessing genetic accommodation involves using a comparative framework to ask whether ancestral plasticity is related to the evolution of a particular trait. Bees are an excellent group for such comparisons because caste-based societies (eusociality) have evolved multiple times independently and extant species exhibit different modes of eusociality. We measured brain and abdominal gene expression in a facultatively eusocial bee, Megalopta genalis, and assessed whether plasticity in this species is functionally linked to eusocial traits in other bee lineages. Caste-biased abdominal genes in M. genalis overlapped significantly with caste-biased genes in obligately eusocial bees. Moreover, caste-biased genes in M. genalis overlapped significantly with genes shown to be rapidly evolving in multiple studies of 10 bee species, particularly for genes in the glycolysis pathway and other genes involved in metabolism. These results provide support for the idea that eusociality can evolve via genetic accommodation, with plasticity in facultatively eusocial species like M. genalis providing a substrate for selection during the evolution of caste in obligately eusocial lineages.
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Affiliation(s)
- Beryl M Jones
- Program in Ecology, Evolution, and Conservation Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Smithsonian Tropical Research Institute, Panama City 20521-9100, Panama
| | - Callum J Kingwell
- Smithsonian Tropical Research Institute, Panama City 20521-9100, Panama
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - William T Wcislo
- Smithsonian Tropical Research Institute, Panama City 20521-9100, Panama
| | - Gene E Robinson
- Program in Ecology, Evolution, and Conservation Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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13
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Séguret A, Bernadou A, Paxton RJ. Facultative social insects can provide insights into the reversal of the longevity/fecundity trade-off across the eusocial insects. CURRENT OPINION IN INSECT SCIENCE 2016; 16:95-103. [PMID: 27720058 DOI: 10.1016/j.cois.2016.06.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 05/27/2016] [Accepted: 06/03/2016] [Indexed: 06/06/2023]
Abstract
In eusocial insects, reversal of the fecundity/longevity trade-off and extreme differences in life histories between castes of the same species garner scientific and public interest. Facultative social species at the threshold of sociality, in which individuals are socially plastic, provide an excellent opportunity to understand the causes and mechanisms underlying this reversal in life history trade-off associated with eusociality. We briefly present the ultimate factors favoring sociality and the association between fecundity and longevity in facultative eusocial insects, including kin selection and disposable soma, as well as proximate mechanisms observed in such species, such as differences in hormone titers and functions. Potential genetic underpinnings of lifespan and fecundity differences between castes are discussed and future research directions are proposed.
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Affiliation(s)
- Alice Séguret
- Institute for Biology, Martin-Luther-University Halle-Wittenberg, Hoher Weg 8, 06120 Halle (Saale), Germany
| | - Abel Bernadou
- Zoology/Evolutionary Biology, Universität Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Robert J Paxton
- Institute for Biology, Martin-Luther-University Halle-Wittenberg, Hoher Weg 8, 06120 Halle (Saale), Germany; iDiv, German Centre for Integrative Biodiversity Research Halle-Jena-Leipzig, Deutscher Platz 5e, 04103 Leipzig, Germany.
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14
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Gadagkar R. Evolution of social behaviour in the primitively eusocial wasp Ropalidia marginata: do we need to look beyond kin selection? Philos Trans R Soc Lond B Biol Sci 2016; 371:20150094. [PMID: 26729933 DOI: 10.1098/rstb.2015.0094] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Ropalidia marginata is a primitively eusocial wasp widely distributed in peninsular India. Although solitary females found a small proportion of nests, the vast majority of new nests are founded by small groups of females. In such multiple foundress nests, a single dominant female functions as the queen and lays eggs, while the rest function as sterile workers and care for the queen's brood. Previous attempts to understand the evolution of social behaviour and altruism in this species have employed inclusive fitness theory (kin selection) as a guiding framework. Although inclusive fitness theory is quite successful in explaining the high propensity of the wasps to found nests in groups, several features of their social organization suggest that forces other than kin selection may also have played a significant role in the evolution of this species. These features include lowering of genetic relatedness owing to polyandry and serial polygyny, nest foundation by unrelated individuals, acceptance of young non-nest-mates, a combination of well-developed nest-mate recognition and lack of intra-colony kin recognition, a combination of meek and docile queens and a decentralized self-organized work force, long reproductive queues with cryptic heir designates and conflict-free queen succession, all resulting in extreme intra-colony cooperation and inter-colony conflict.
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Affiliation(s)
- Raghavendra Gadagkar
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560012, India
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15
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Kapheim KM, Nonacs P, Smith AR, Wayne RK, Wcislo WT. Kinship, parental manipulation and evolutionary origins of eusociality. Proc Biol Sci 2015; 282:20142886. [PMID: 25694620 DOI: 10.1098/rspb.2014.2886] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
One of the hallmarks of eusociality is that workers forego their own reproduction to assist their mother in raising siblings. This seemingly altruistic behaviour may benefit workers if gains in indirect fitness from rearing siblings outweigh the loss of direct fitness. If worker presence is advantageous to mothers, however, eusociality may evolve without net benefits to workers. Indirect fitness benefits are often cited as evidence for the importance of inclusive fitness in eusociality, but have rarely been measured in natural populations. We compared inclusive fitness of alternative social strategies in the tropical sweat bee, Megalopta genalis, for which eusociality is optional. Our results show that workers have significantly lower inclusive fitness than females that found their own nests. In mathematical simulations based on M. genalis field data, eusociality cannot evolve with reduced intra-nest relatedness. The simulated distribution of alternative social strategies matched observed distributions of M. genalis social strategies when helping behaviour was simulated as the result of maternal manipulation, but not as worker altruism. Thus, eusociality in M. genalis is best explained through kin selection, but the underlying mechanism is likely maternal manipulation.
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Affiliation(s)
- Karen M Kapheim
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322-5305, USA
| | - Peter Nonacs
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA 90095, USA
| | - Adam R Smith
- Department of Biological Sciences, George Washington University, Washington, DC 20052, USA
| | - Robert K Wayne
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA 90095, USA
| | - William T Wcislo
- Smithsonian Tropical Research Institute, Apartado 0843, Balboa, Republic of Panama
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16
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Jones BM, Wcislo WT, Robinson GE. Developmental Transcriptome for a Facultatively Eusocial Bee, Megalopta genalis. G3 (BETHESDA, MD.) 2015; 5:2127-35. [PMID: 26276382 PMCID: PMC4592995 DOI: 10.1534/g3.115.021261] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 08/12/2015] [Indexed: 11/18/2022]
Abstract
Transcriptomes provide excellent foundational resources for mechanistic and evolutionary analyses of complex traits. We present a developmental transcriptome for the facultatively eusocial bee Megalopta genalis, which represents a potential transition point in the evolution of eusociality. A de novo transcriptome assembly of Megalopta genalis was generated using paired-end Illumina sequencing and the Trinity assembler. Males and females of all life stages were aligned to this transcriptome for analysis of gene expression profiles throughout development. Gene Ontology analysis indicates that stage-specific genes are involved in ion transport, cell-cell signaling, and metabolism. A number of distinct biological processes are upregulated in each life stage, and transitions between life stages involve shifts in dominant functional processes, including shifts from transcriptional regulation in embryos to metabolism in larvae, and increased lipid metabolism in adults. We expect that this transcriptome will provide a useful resource for future analyses to better understand the molecular basis of the evolution of eusociality and, more generally, phenotypic plasticity.
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Affiliation(s)
- Beryl M Jones
- Program in Ecology, Evolution, and Conservation Biology, University of Illinois, Urbana, Illinois 61801 Smithsonian Tropical Research Institute, Panama City, Panama 20521-9100 Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois 61801
| | - William T Wcislo
- Smithsonian Tropical Research Institute, Panama City, Panama 20521-9100
| | - Gene E Robinson
- Program in Ecology, Evolution, and Conservation Biology, University of Illinois, Urbana, Illinois 61801 Department of Entomology, University of Illinois, Urbana, Illinois 61801 Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois 61801 Neuroscience Program, University of Illinois, Urbana, Illinois 61801
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Quiñones AE, Wcislo WT. Cryptic extended brood care in the facultatively eusocial sweat bee Megalopta genalis. INSECTES SOCIAUX 2015; 62:307-313. [PMID: 26097252 PMCID: PMC4469088 DOI: 10.1007/s00040-015-0409-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 03/10/2015] [Accepted: 03/19/2015] [Indexed: 06/04/2023]
Abstract
As a result of different brood cell provisioning strategies, nest-making insects may differ in the extent to which adults regularly provide extended parental care to their brood beyond nest defense. Mass-provisioning species cache the entire food supply needed for larval development prior to the oviposition and typically seal the brood cell. It is usually assumed that there is no regular contact between the adult(s) and brood. Here, we show that the bee, Megalopta genalis, expresses a form of cryptic brood care, which would not be observed during normal development. Following experimental injections of different provisioning materials into brood cells, foundresses reopened manipulated cells and the brood were aborted in some cases, implying that the foundresses assessed conditions within the cells. In aborted cells, foundresses sometimes laid a second egg after first removing dead larvae, previously stored pollen and contaminants. Our results show that hygienic brood care can be cryptic and hence may be more widespread than previously believed, lending support to the hypothesis that extended parental care is a preadaptation toward eusociality.
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Affiliation(s)
- A. E. Quiñones
- />Theoretical biology group, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - W. T. Wcislo
- />Smithsonian Tropical Research Institute, 0843-03092 Balboa, Apartado Republic of Panama
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