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Mueller UG, Himler AG, Farrior CE. Life history, nest longevity, sex ratio, and nest architecture of the fungus-growing ant Mycetosoritis hartmanni (Formicidae: Attina). PLoS One 2023; 18:e0289146. [PMID: 37494382 PMCID: PMC10370743 DOI: 10.1371/journal.pone.0289146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 07/12/2023] [Indexed: 07/28/2023] Open
Abstract
Mycetosoritis hartmanni is a rarely collected fungus-farming ant of North America. We describe life history and nest architecture for a M. hartmanni population in central Texas, USA. Colonies are monogynous with typically less than 100 workers (average 47.6 workers, maximum 148 workers). Nests occur always in sand and have a uniform architecture with 1-3 underground garden chambers arranged along a vertical tunnel, with the deepest gardens 50-70 cm deep. Foragers are active primarily between April and October. After reduced activity between November and February, egg laying by queens resumes in April, and the first worker pupae develop in early June. Reproductive females and males are reared primarily in July and August, with proportionally more females produced early in summer (protogyny). Mating flights and founding of new nests by mated females occur in late June to August, but may extend through September. For a cohort of 150 established nests (nests that had survived at least one year after nest founding), the estimated mortality rate was 0.41-0.53, the estimated average lifespan for these nests was 1.9-2.5 years, and the longest-living nests were observed to live for 6 years. These life-history parameters for M. hartmanni in central Texas are consistent with information from additional M. hartmanni nests observed throughout the range of this species from eastern Louisiana to southern Texas. Throughout its range in the USA, M. hartmanni can be locally very abundant in sun-exposed, sandy soil. Abundance of M. hartmanni seems so far relatively unaffected by invasive fire ants, and at present M. hartmanni does not appear to be an endangered species.
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Affiliation(s)
- Ulrich G Mueller
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, United States of America
| | - Anna G Himler
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, United States of America
- Department of Biology, College of Idaho, Caldwell, ID, United States of America
| | - Caroline E Farrior
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, United States of America
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Majoe M, Libbrecht R, Foitzik S, Nehring V. Queen loss increases worker survival in leaf-cutting ants under paraquat-induced oxidative stress. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190735. [PMID: 33678018 PMCID: PMC7938173 DOI: 10.1098/rstb.2019.0735] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2020] [Indexed: 01/18/2023] Open
Abstract
Longevity is traded off with fecundity in most solitary species, but the two traits are positively linked in social insects. In ants, the most fecund individuals (queens and kings) live longer than the non-reproductive individuals, the workers. In many species, workers may become fertile following queen loss, and recent evidence suggests that worker fecundity extends worker lifespan. We postulated that this effect is in part owing to improved resilience to oxidative stress, and tested this hypothesis in three Myrmicine ants: Temnothorax rugatulus, and the leaf-cutting ants Atta colombica and Acromyrmex echinatior. We removed the queen from colonies to induce worker reproduction and subjected workers to oxidative stress. Oxidative stress drastically reduced survival, but this effect was less pronounced in leaf-cutting ant workers from queenless nests. We also found that, irrespective of oxidative stress, outside workers died earlier than inside workers did, likely because they were older. Since At. colombica workers cannot produce fertile offspring, our results indicate that direct reproduction is not necessary to extend the lives of queenless workers. Our findings suggest that workers are less resilient to oxidative stress in the presence of the queen, and raise questions on the proximate and ultimate mechanisms underlying socially mediated variation in worker lifespan. This article is part of the theme issue 'Ageing and sociality: why, when and how does sociality change ageing patterns?'
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Affiliation(s)
- Megha Majoe
- Institute of Organismic and Molecular Evolution, Johannes Gutenberg University Mainz, Hanns Dieter Hüsch Weg 15, 55128 Mainz, Germany
- Institute for Biology I (Zoology), University of Freiburg, Hauptstrasse 1, D-79104 Freiburg, Germany
| | - Romain Libbrecht
- Institute of Organismic and Molecular Evolution, Johannes Gutenberg University Mainz, Hanns Dieter Hüsch Weg 15, 55128 Mainz, Germany
| | - Susanne Foitzik
- Institute of Organismic and Molecular Evolution, Johannes Gutenberg University Mainz, Hanns Dieter Hüsch Weg 15, 55128 Mainz, Germany
| | - Volker Nehring
- Institute for Biology I (Zoology), University of Freiburg, Hauptstrasse 1, D-79104 Freiburg, Germany
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Stürup M, Nash DR, Hughes WOH, Boomsma JJ. Sperm mixing in the polyandrous leaf-cutting ant Acromyrmex echinatior. Ecol Evol 2014; 4:3571-82. [PMID: 25478149 PMCID: PMC4224532 DOI: 10.1002/ece3.1176] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 06/25/2014] [Accepted: 07/02/2014] [Indexed: 11/08/2022] Open
Abstract
The insemination of queens by sperm from multiple males (polyandry) has evolved in a number of eusocial insect lineages despite the likely costs of the behavior. The selective advantages in terms of colony fitness must therefore also be significant and there is now good evidence that polyandry increases genetic variation among workers, thereby improving the efficiency of division of labor, resistance against disease, and diluting the impact of genetically incompatible matings. However, these advantages will only be maximized if the sperm of initially discrete ejaculates are mixed when stored in queen spermathecae and used for egg fertilization in a "fair raffle." Remarkably, however, very few studies have addressed the level of sperm mixing in social insects. Here we analyzed sperm use over time in the highly polyandrous leaf-cutting ant Acromyrmex echinatior. We genotyped cohorts of workers produced either 2 months apart or up to over a year apart, and batches of eggs laid up to over 2 years apart, and tested whether fluctuations in patriline distributions deviated from random. We show that the representation of father males in both egg and worker cohorts does not change over time, consistent with obligatorily polyandrous queens maximizing their fitness when workers are as genetically diverse as possible.
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Affiliation(s)
- Marlene Stürup
- Department of Biology, Centre for Social Evolution, University of Copenhagen Universitetsparken 15, Copenhagen, 2100, Denmark
| | - David R Nash
- Department of Biology, Centre for Social Evolution, University of Copenhagen Universitetsparken 15, Copenhagen, 2100, Denmark
| | - William O H Hughes
- Department of Biology, Centre for Social Evolution, University of Copenhagen Universitetsparken 15, Copenhagen, 2100, Denmark ; School of Life Sciences, University of Sussex Brighton, BN1 9QG, UK
| | - Jacobus J Boomsma
- Department of Biology, Centre for Social Evolution, University of Copenhagen Universitetsparken 15, Copenhagen, 2100, Denmark
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Oettler J, Dijkstra MB, Heinze J. Egg-laying "intermorphs" in the ant Crematogaster smithi neither affect sexual production nor male parentage. PLoS One 2013; 8:e75278. [PMID: 24130699 PMCID: PMC3794939 DOI: 10.1371/journal.pone.0075278] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 08/14/2013] [Indexed: 11/18/2022] Open
Abstract
We study male parentage and between-colony variation in sex allocation and sexual production in the desert ant Crematogaster smithi, which usually has only one singly-mated queen per nest. Colonies of this species are known to temporarily store nutrients in the large fat body of intermorphs, a specialized female caste intermediate in morphology between queens and workers. Intermorphs repackage at least part of this fat into consumable but viable male-destined eggs. If these eggs sometimes develop instead of being eaten, intermorphs will be reproductive competitors of the queen but--due to relatedness asymmetries--allies of their sister worker. Using genetic markers we found a considerable proportion of non-queen sons in some, but not all, colonies. Even though intermorphs produce ∼1.7× more eggs than workers, their share in the parentage of adult males is estimated to be negligible due to their small number compared to workers. Furthermore, neither colony-level sex allocation nor overall sexual production was correlated with intermorph occurrence or number. We conclude that intermorph-laid eggs typically do not survive and that the storage of nutrients and their redistribution as eggs by intermorphs is effectively altruistic.
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Affiliation(s)
- Jan Oettler
- Biologie I, Universität Regensburg, Regensburg, Germany
| | - Michiel B. Dijkstra
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Jürgen Heinze
- Biologie I, Universität Regensburg, Regensburg, Germany
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Kümmerli R, Keller L. Between-year variation in population sex ratio increases with complexity of the breeding system in Hymenoptera. Am Nat 2011; 177:835-46. [PMID: 21597259 DOI: 10.1086/659951] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
While adaptive adjustment of sex ratio in the function of colony kin structure and food availability commonly occurs in social Hymenoptera, long-term studies have revealed substantial unexplained between-year variation in sex ratio at the population level. In order to identify factors that contribute to increased between-year variation in population sex ratio, we conducted a comparative analysis across 47 Hymenoptera species differing in their breeding system. We found that between-year variation in population sex ratio steadily increased as one moved from solitary species, to primitively eusocial species, to single-queen eusocial species, to multiple-queen eusocial species. Specifically, between-year variation in population sex ratio was low (6.6% of total possible variation) in solitary species, which is consistent with the view that in solitary species, sex ratio can vary only in response to fluctuations in ecological factors such as food availability. In contrast, we found significantly higher (19.5%) between-year variation in population sex ratio in multiple-queen eusocial species, which supports the view that in these species, sex ratio can also fluctuate in response to temporal changes in social factors such as queen number and queen-worker control over sex ratio, as well as factors influencing caste determination. The simultaneous adjustment of sex ratio in response to temporal fluctuations in ecological and social factors seems to preclude the existence of a single sex ratio optimum. The absence of such an optimum may reflect an additional cost associated with the evolution of complex breeding systems in Hymenoptera societies.
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Affiliation(s)
- Rolf Kümmerli
- Department of Environmental Microbiology, Swiss Federal Institute of Aquatic Science and Technology (Eawag), Überlandstrasse, Dübendorf, Switzerland.
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BONCKAERT W, Van ZWEDEN JS, D’ETTORRE P, BILLEN J, WENSELEERS T. Colony stage and not facultative policing explains pattern of worker reproduction in the Saxon wasp. Mol Ecol 2011; 20:3455-68. [DOI: 10.1111/j.1365-294x.2011.05200.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Dijkstra MB, van Zweden JS, Dirchsen M, Boomsma JJ. Workers of Acromyrmex echinatior leafcutter ants police worker-laid eggs, but not reproductive workers. Anim Behav 2010. [DOI: 10.1016/j.anbehav.2010.06.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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JOHNSON ELIZABETHL, CUNNINGHAM TYLERW, MARRINER SARAHM, KOVACS JENNIFERL, HUNT BRENDANG, BHAKTA DIMPALB, GOODISMAN MICHAELAD. Resource allocation in a social wasp: effects of breeding system and life cycle on reproductive decisions. Mol Ecol 2009; 18:2908-20. [DOI: 10.1111/j.1365-294x.2009.04240.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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