1
|
Schultner E, Wallner T, Dofka B, Brülhart J, Heinze J, Freitak D, Pokorny T, Oettler J. Queens control caste allocation in the ant Cardiocondyla obscurior. Proc Biol Sci 2023; 290:20221784. [PMID: 36750190 PMCID: PMC9904955 DOI: 10.1098/rspb.2022.1784] [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: 09/08/2022] [Accepted: 01/17/2023] [Indexed: 02/09/2023] Open
Abstract
Social insect queens and workers can engage in conflict over reproductive allocation when they have different fitness optima. Here, we show that queens have control over queen-worker caste allocation in the ant Cardiocondyla obscurior, a species in which workers lack reproductive organs. We describe crystalline deposits that distinguish castes from the egg stage onwards, providing the first report of a discrete trait that can be used to identify ant caste throughout pre-imaginal development. The comparison of queen and worker-destined eggs and larvae revealed size and weight differences in late development, but no discernible differences in traits that may be used in social interactions, including hair morphology and cuticular odours. In line with a lack of caste-specific traits, adult workers treated developing queens and workers indiscriminately. Together with previous studies demonstrating queen control over sex allocation, these results show that queens control reproductive allocation in C. obscurior and suggest that the fitness interests of colony members are aligned to optimize resource allocation in this ant.
Collapse
Affiliation(s)
- Eva Schultner
- Zoology/Evolutionary Biology, University of Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - Tobias Wallner
- Zoology/Evolutionary Biology, University of Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - Benjamin Dofka
- Zoology/Evolutionary Biology, University of Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - Jeanne Brülhart
- Zoology/Evolutionary Biology, University of Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - Jürgen Heinze
- Zoology/Evolutionary Biology, University of Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - Dalial Freitak
- Institute for Biology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
| | - Tamara Pokorny
- Zoology/Evolutionary Biology, University of Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - Jan Oettler
- Zoology/Evolutionary Biology, University of Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| |
Collapse
|
2
|
Jud SL, Knebel D, Ulrich Y. Intergenerational genotypic interactions drive collective behavioural cycles in a social insect. Proc Biol Sci 2022; 289:20221273. [PMID: 36321497 PMCID: PMC9627708 DOI: 10.1098/rspb.2022.1273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Many social animals display collective activity cycles based on synchronous behavioural oscillations across group members. A classic example is the colony cycle of army ants, where thousands of individuals undergo stereotypical biphasic behavioural cycles of about one month. Cycle phases coincide with brood developmental stages, but the regulation of this cycle is otherwise poorly understood. Here, we probe the regulation of cycle duration through interactions between brood and workers in an experimentally amenable army ant relative, the clonal raider ant. We first establish that cycle length varies across clonal lineages using long-term monitoring data. We then investigate the putative sources and impacts of this variation in a cross-fostering experiment with four lineages combining developmental, morphological and automated behavioural tracking analyses. We show that cycle length variation stems from variation in the duration of the larval developmental stage, and that this stage can be prolonged not only by the clonal lineage of brood (direct genetic effects), but also of the workers (indirect genetic effects). We find similar indirect effects of worker line on brood adult size and, conversely (but more surprisingly), indirect genetic effects of the brood on worker behaviour (walking speed and time spent in the nest).
Collapse
Affiliation(s)
- Stephanie L. Jud
- Institute of Integrative Biology, ETHZ Zürich, Zürich 8092, Switzerland
| | - Daniel Knebel
- Max Planck Institute for Chemical Ecology, Hans-Knöll-Strasse 8, Jena 07745, Germany
| | - Yuko Ulrich
- Institute of Integrative Biology, ETHZ Zürich, Zürich 8092, Switzerland,Max Planck Institute for Chemical Ecology, Hans-Knöll-Strasse 8, Jena 07745, Germany
| |
Collapse
|
3
|
Walsh JT, Garnier S, Linksvayer TA. Ant Collective Behavior Is Heritable and Shaped by Selection. Am Nat 2020; 196:541-554. [PMID: 33064586 DOI: 10.1086/710709] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractCollective behaviors are widespread in nature and usually assumed to be strongly shaped by natural selection. However, the degree to which variation in collective behavior is heritable and has fitness consequences-the two prerequisites for evolution by natural selection-is largely unknown. We used a new pharaoh ant (Monomorium pharaonis) mapping population to estimate the heritability, genetic correlations, and fitness consequences of three collective behaviors (foraging, aggression, and exploration), as well as of body size, sex ratio, and caste ratio. Heritability estimates for the collective behaviors were moderate, ranging from 0.17 to 0.32, but lower than our estimates for the heritability of caste ratio, sex ratio, and body size of new workers, queens, and males. Moreover, variation in collective behaviors among colonies was phenotypically correlated, suggesting that selection may shape multiple colony collective behaviors simultaneously. Finally, we found evidence for directional selection that was similar in strength to estimates of selection in natural populations. Altogether, our study begins to elucidate the genetic architecture of collective behavior and is one of the first studies to demonstrate that it is shaped by selection.
Collapse
|
4
|
Walsh J, Pontieri L, d'Ettorre P, Linksvayer TA. Ant cuticular hydrocarbons are heritable and associated with variation in colony productivity. Proc Biol Sci 2020; 287:20201029. [PMID: 32517627 DOI: 10.1098/rspb.2020.1029] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In social insects, cuticular hydrocarbons function in nest-mate recognition and also provide a waxy barrier against desiccation, but basic evolutionary features, including the heritability of hydrocarbon profiles and how they are shaped by natural selection are largely unknown. We used a new pharaoh ant (Monomorium pharaonis) laboratory mapping population to estimate the heritability of individual cuticular hydrocarbons, genetic correlations between hydrocarbons, and fitness consequences of phenotypic variation in the hydrocarbons. Individual hydrocarbons had low to moderate estimated heritability, indicating that some compounds provide more information about genetic relatedness and can also better respond to natural selection. Strong genetic correlations between compounds are likely to constrain independent evolutionary trajectories, which is expected, given that many hydrocarbons share biosynthetic pathways. Variation in cuticular hydrocarbons was associated with variation in colony productivity, with some hydrocarbons experiencing strong directional selection. Altogether, this study builds on our knowledge of the genetic architecture of the social insect hydrocarbon profile and indicates that hydrocarbon variation is shaped by natural selection.
Collapse
Affiliation(s)
- Justin Walsh
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Luigi Pontieri
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark
| | - Patrizia d'Ettorre
- Laboratory of Experimental and Comparative Ethology (LEEC), University of Paris 13, Sorbonne Paris Cité, France
| | | |
Collapse
|
5
|
Morsky B, Smolla M, Akçay E. Evolution of contribution timing in public goods games. Proc Biol Sci 2020; 287:20200735. [PMID: 32453985 DOI: 10.1098/rspb.2020.0735] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Life-history strategies are a crucial aspect of life, which are complicated in group-living species, where pay-offs additionally depend on others' behaviours. Previous theoretical models of public goods games have generally focused on the amounts individuals contribute to the public good. Yet a much less-studied strategic aspect of public goods games, the timing of contributions, can also have dramatic consequences for individual and collective performance. Here, we develop two stage game theoretical models to explore how the timing of contributions evolves. In the first stage, individuals contribute to a threshold public good based on a performance schedule. The second stage begins once the threshold is met, and the individuals then compete as a function of their performance. We show how contributing rapidly is not necessarily optimal, because delayers can act as 'cheats,' avoiding contributing while reaping the benefits of the public good. However, delaying too long can put the delayers at a disadvantage as they may be ill-equipped to compete. These effects lead to bistability in a single group, and spatial diversity among multiple interacting groups.
Collapse
Affiliation(s)
- Bryce Morsky
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Marco Smolla
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Erol Akçay
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
6
|
Singh R, Linksvayer TA. Wolbachia-infected ant colonies have increased reproductive investment and an accelerated life cycle. J Exp Biol 2020; 223:jeb220079. [PMID: 32253286 DOI: 10.1242/jeb.220079] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 03/26/2020] [Indexed: 12/31/2022]
Abstract
Wolbachia is a widespread genus of maternally transmitted endosymbiotic bacteria that often manipulates the reproductive strategy and life history of its hosts to favor its own transmission. Wolbachia-mediated phenotypic effects are well characterized in solitary hosts, but effects in social hosts are unclear. The invasive pharaoh ant, Monomorium pharaonis, shows natural variation in Wolbachia infection between colonies and can be readily bred under laboratory conditions. We previously showed that Wolbachia-infected pharaoh ant colonies had more queen-biased sex ratios than uninfected colonies, which is expected to favor the spread of maternally transmitted Wolbachia Here, we further characterize the effects of Wolbachia on the short- and longer-term reproductive and life history traits of pharaoh ant colonies. First, we characterized the reproductive differences between naturally infected and uninfected colonies at three discrete time points and found that infected colonies had higher reproductive investment (i.e. infected colonies produced more new queens), particularly when existing colony queens were 3 months old. Next, we compared the long-term growth and reproduction dynamics of infected and uninfected colonies across their whole life cycle. Infected colonies had increased colony-level growth and early colony reproduction, resulting in a shorter colony life cycle, when compared with uninfected colonies.
Collapse
Affiliation(s)
- Rohini Singh
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | |
Collapse
|
7
|
Reiner Brodetzki T, Brodetzki G, Feinerman O, Hefetz A. Worker demography and behavior in a supercolonial ant colony: The case of the desert ant
Cataglyphis niger. Ethology 2019. [DOI: 10.1111/eth.12960] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Tali Reiner Brodetzki
- School of Zoology George S. Wise Faculty of Life Sciences Tel Aviv University Tel Aviv Israel
| | - Guy Brodetzki
- Physics Department Tel Aviv University Tel Aviv Israel
| | - Ofer Feinerman
- Department of Physics of Complex Systems Weizmann Institute of Science Rehovot Israel
| | - Abraham Hefetz
- School of Zoology George S. Wise Faculty of Life Sciences Tel Aviv University Tel Aviv Israel
| |
Collapse
|
8
|
Warner MR, Qiu L, Holmes MJ, Mikheyev AS, Linksvayer TA. Convergent eusocial evolution is based on a shared reproductive groundplan plus lineage-specific plastic genes. Nat Commun 2019; 10:2651. [PMID: 31201311 PMCID: PMC6570765 DOI: 10.1038/s41467-019-10546-w] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 05/14/2019] [Indexed: 12/31/2022] Open
Abstract
Eusociality has convergently evolved multiple times, but the genomic basis of caste-based division of labor and degree to which independent origins of eusociality have utilized common genes remain largely unknown. Here we characterize caste-specific transcriptomic profiles across development and adult body segments from pharaoh ants (Monomorium pharaonis) and honey bees (Apis mellifera), representing two independent origins of eusociality. We identify a substantial shared core of genes upregulated in the abdomens of queen ants and honey bees that also tends to be upregulated in mated female flies, suggesting that these genes are part of a conserved insect reproductive groundplan. Outside of this shared groundplan, few genes are differentially expressed in common. Instead, the majority of the thousands of caste-associated genes are plastically expressed, rapidly evolving, and relatively evolutionarily young. These results emphasize that the recruitment of both highly conserved and lineage-specific genes underlie the convergent evolution of novel traits such as eusociality. Eusocial caste systems have evolved independently multiple times. Here, Warner et al. investigate the amount of shared vs. lineage-specific genes involved in the evolution of caste in pharaoh ants and honey bees by comparing transcriptomes across tissues, developmental stages, and castes.
Collapse
Affiliation(s)
| | - Lijun Qiu
- Okinawa Institute of Science and Technology, Okinawa, 904-0495, Japan
| | - Michael J Holmes
- Okinawa Institute of Science and Technology, Okinawa, 904-0495, Japan.,School of Life and Environmental Science, University of Sydney, Sydney, 2006, Australia
| | - Alexander S Mikheyev
- Okinawa Institute of Science and Technology, Okinawa, 904-0495, Japan.,Research School of Biology, Australian National University, Canberra, 0200, Australia
| | | |
Collapse
|
9
|
Warner MR, Mikheyev AS, Linksvayer TA. Transcriptomic basis and evolution of the ant nurse-larval social interactome. PLoS Genet 2019; 15:e1008156. [PMID: 31107868 DOI: 10.1101/514356] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 05/31/2019] [Accepted: 04/24/2019] [Indexed: 05/20/2023] Open
Abstract
Development is often strongly regulated by interactions among close relatives, but the underlying molecular mechanisms are largely unknown. In eusocial insects, interactions between caregiving worker nurses and larvae regulate larval development and resultant adult phenotypes. Here, we begin to characterize the social interactome regulating ant larval development by collecting and sequencing the transcriptomes of interacting nurses and larvae across time. We find that the majority of nurse and larval transcriptomes exhibit parallel expression dynamics across larval development. We leverage this widespread nurse-larva gene co-expression to infer putative social gene regulatory networks acting between nurses and larvae. Genes with the strongest inferred social effects tend to be peripheral elements of within-tissue regulatory networks and are often known to encode secreted proteins. This includes interesting candidates such as the nurse-expressed giant-lens, which may influence larval epidermal growth factor signaling, a pathway known to influence various aspects of insect development. Finally, we find that genes with the strongest signatures of social regulation tend to experience relaxed selective constraint and are evolutionarily young. Overall, our study provides a first glimpse into the molecular and evolutionary features of the social mechanisms that regulate all aspects of social life.
Collapse
Affiliation(s)
- Michael R Warner
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Alexander S Mikheyev
- Ecology and Evolution Unit, Okinawa Institute of Science and Technology, Onna, Okinawa, Japan
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Timothy A Linksvayer
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| |
Collapse
|
10
|
Warner MR, Mikheyev AS, Linksvayer TA. Transcriptomic basis and evolution of the ant nurse-larval social interactome. PLoS Genet 2019; 15:e1008156. [PMID: 31107868 PMCID: PMC6544314 DOI: 10.1371/journal.pgen.1008156] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 05/31/2019] [Accepted: 04/24/2019] [Indexed: 12/13/2022] Open
Abstract
Development is often strongly regulated by interactions among close relatives, but the underlying molecular mechanisms are largely unknown. In eusocial insects, interactions between caregiving worker nurses and larvae regulate larval development and resultant adult phenotypes. Here, we begin to characterize the social interactome regulating ant larval development by collecting and sequencing the transcriptomes of interacting nurses and larvae across time. We find that the majority of nurse and larval transcriptomes exhibit parallel expression dynamics across larval development. We leverage this widespread nurse-larva gene co-expression to infer putative social gene regulatory networks acting between nurses and larvae. Genes with the strongest inferred social effects tend to be peripheral elements of within-tissue regulatory networks and are often known to encode secreted proteins. This includes interesting candidates such as the nurse-expressed giant-lens, which may influence larval epidermal growth factor signaling, a pathway known to influence various aspects of insect development. Finally, we find that genes with the strongest signatures of social regulation tend to experience relaxed selective constraint and are evolutionarily young. Overall, our study provides a first glimpse into the molecular and evolutionary features of the social mechanisms that regulate all aspects of social life.
Collapse
Affiliation(s)
- Michael R. Warner
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Alexander S. Mikheyev
- Ecology and Evolution Unit, Okinawa Institute of Science and Technology, Onna, Okinawa, Japan
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Timothy A. Linksvayer
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| |
Collapse
|
11
|
Ant nurse workers exhibit behavioural and transcriptomic signatures of specialization on larval stage. Anim Behav 2018. [DOI: 10.1016/j.anbehav.2018.05.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|