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Law SJ, Allison SD, Davies AB, Flores-Moreno H, Wijas BJ, Yatsko AR, Zhou Y, Zanne AE, Eggleton P. The challenge of estimating global termite methane emissions. GLOBAL CHANGE BIOLOGY 2024; 30:e17390. [PMID: 38899583 DOI: 10.1111/gcb.17390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 05/30/2024] [Accepted: 06/04/2024] [Indexed: 06/21/2024]
Abstract
Methane is a powerful greenhouse gas, more potent than carbon dioxide, and emitted from a variety of natural sources including wetlands, permafrost, mammalian guts and termites. As increases in global temperatures continue to break records, quantifying the magnitudes of key methane sources has never been more pertinent. Over the last 40 years, the contribution of termites to the global methane budget has been subject to much debate. The most recent estimates of termite emissions range between 9 and 15 Tg CH4 year-1, approximately 4% of emissions from natural sources (excluding wetlands). However, we argue that the current approach for estimating termite contributions to the global methane budget is flawed. Key parameters, namely termite methane emissions from soil, deadwood, living tree stems, epigeal mounds and arboreal nests, are largely ignored in global estimates. This omission occurs because data are lacking and research objectives, crucially, neglect variation in termite ecology. Furthermore, inconsistencies in data collection methods prohibit the pooling of data required to compute global estimates. Here, we summarise the advances made over the last 40 years and illustrate how different aspects of termite ecology can influence the termite contribution to global methane emissions. Additionally, we highlight technological advances that may help researchers investigate termite methane emissions on a larger scale. Finally, we consider dynamic feedback mechanisms of climate warming and land-use change on termite methane emissions. We conclude that ultimately the global contribution of termites to atmospheric methane remains unknown and thus present an alternative framework for estimating their emissions. To significantly improve estimates, we outline outstanding questions to guide future research efforts.
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Affiliation(s)
- Stephanie J Law
- Life Sciences Department, The Natural History Museum, London, UK
| | - Steven D Allison
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California, USA
- Department of Earth System Science, University of California, Irvine, California, USA
| | - Andrew B Davies
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | | | | | - Abbey R Yatsko
- Department of Biology, University of Miami, Miami, Florida, USA
| | - Yong Zhou
- Department of Wildland Resources, Utah State University, Logan, Utah, USA
- Ecology Center, Utah State University, Logan, Utah, USA
| | - Amy E Zanne
- Department of Biology, University of Miami, Miami, Florida, USA
- Cary Institute of Ecosystem Studies, Millbrook, New York, USA
| | - Paul Eggleton
- Life Sciences Department, The Natural History Museum, London, UK
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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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Sanmartín-Villar I. Social buffer or avoidance depends on the similarity of stress between queen ants. Curr Zool 2022; 69:181-191. [PMID: 37091993 PMCID: PMC10120981 DOI: 10.1093/cz/zoac031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 04/18/2022] [Indexed: 11/13/2022] Open
Abstract
Abstract
The association of unrelated ant queens (pleometrosis) is supposed to improve nest foundation and competitiveness under environmental stress, but its evolutionary maintenance is difficult to explain because only one of the queens survives after nest foundation. My aim was to test the potential effect of queen association as a social buffer, i.e. as a mechanism reducing stress and improving fitness due to the benefits of social contact. I analysed the survival, fecundity, and behaviour of isolated and paired Lasius flavus queens exposed and not exposed to stressors (disturbing environmental conditions). I found no difference in survivorship between isolated and paired queens or between stressed and unstressed isolated queens. Groups in which one or two paired queens were stressed showed higher mortality. Unstressed queens died similarly to their stressed nestmates, suggesting stress transmission. A trend suggested that paired queens produced eggs more quickly, but eggs were produced similarly between isolated and paired queens. Social avoidance was observed in groups with one stressed and one unstressed queen. However, the groups with two stressed queens showed the expected behaviours according to social buffering: lower mobility and more interindividual inspection. My findings suggest the synergistic effect of pleometrosis and stress and the dependence of stress level similarity between nestmates on social buffering or rejection on ant queens.
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Affiliation(s)
- Iago Sanmartín-Villar
- ECOEVO Lab, Escola de Enxeñaría Forestal, Campus A Xunqueira, Universidade de Vigo, Pontevedra, Galiza, Spain
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4
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Intersection between parental investment, transgenerational immunity, and termite sociality in the face of disease: a theoretical approach. Behav Ecol Sociobiol 2022. [DOI: 10.1007/s00265-022-03128-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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5
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Ostwald MM, Guo X, Wong T, Malaekeh A, Harrison JF, Fewell JH. Cooperation among unrelated ant queens provides persistent growth and survival benefits during colony ontogeny. Sci Rep 2021; 11:8332. [PMID: 33859275 PMCID: PMC8050306 DOI: 10.1038/s41598-021-87797-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 03/25/2021] [Indexed: 02/02/2023] Open
Abstract
The fitness consequences of cooperation can vary across an organism's lifespan. For non-kin groups, especially, social advantages must balance intrinsic costs of cooperating with non-relatives. In this study, we asked how challenging life history stages can promote stable, long-term alliances among unrelated ant queens. We reared single- and multi-queen colonies of the primary polygynous harvester ant, Pogonomyrmex californicus, from founding through the first ten months of colony growth, when groups face high mortality risks. We found that colonies founded by multiple, unrelated queens experienced significant survival and growth advantages that outlasted the colony founding period. Multi-queen colonies experienced lower mortality than single-queen colonies, and queens in groups experienced lower mortality than solitary queens. Further, multi-queen colonies produced workers at a faster rate than did single-queen colonies, even while experiencing lower per-queen worker production costs. Additionally, we characterized ontogenetic changes in the organization of labor, and observed increasing and decreasing task performance diversity by workers and queens, respectively, as colonies grew. This dynamic task allocation likely reflects a response to the changing role of queens as they are increasingly able to delegate risky and costly tasks to an expanding workforce. Faster worker production in multi-queen colonies may beneficially accelerate this behavioral transition from a vulnerable parent-offspring group to a stable, growing colony. These combined benefits of cooperation may facilitate the retention of multiple unrelated queens in mature colonies despite direct fitness costs, providing insight into the evolutionary drivers of stable associations between unrelated individuals.
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Affiliation(s)
| | - Xiaohui Guo
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Tyler Wong
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Armon Malaekeh
- 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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6
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Aguero CM, Eyer P, Martin JS, Bulmer MS, Vargo EL. Natural variation in colony inbreeding does not influence susceptibility to a fungal pathogen in a termite. Ecol Evol 2021; 11:3072-3083. [PMID: 33841768 PMCID: PMC8019025 DOI: 10.1002/ece3.7233] [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] [Received: 08/13/2020] [Revised: 01/08/2021] [Accepted: 01/15/2021] [Indexed: 01/26/2023] Open
Abstract
Reduced genetic diversity through inbreeding can negatively affect pathogen resistance. This relationship becomes more complicated in social species, such as social insects, since the chance of disease transmission increases with the frequency of interactions among individuals. However, social insects may benefit from social immunity, whereby individual physiological defenses may be bolstered by collective-level immune responses, such as grooming or sharing of antimicrobial substance through trophallaxis. We set out to determine whether differences in genetic diversity between colonies of the subterranean termite, Reticulitermes flavipes, accounts for colony survival against pathogens. We sampled colonies throughout the United States (Texas, North Carolina, Maryland, and Massachusetts) and determined the level of inbreeding of each colony. To assess whether genetically diverse colonies were better able to survive exposure to diverse pathogens, we challenged groups of termite workers with two strains of a pathogenic fungus, one local strain present in the soil surrounding sampled colonies and another naïve strain, collected outside the range of this species. We found natural variation in the level of inbreeding between colonies, but this variation did not explain differences in susceptibility to either pathogen. Although the naïve strain was found to be more hazardous than the local strain, colony resistance was correlated between two strains, meaning that colonies had either relatively high or low susceptibility to both strains regardless of their inbreeding coefficient. Overall, our findings may reflect differential virulence between the strains, immune priming of the colonies via prior exposure to the local strain, or a coevolved resistance toward this strain. They also suggest that colony survival may rely more upon additional factors, such as different behavioral response thresholds or the influence of a specific genetic background, rather than the overall genetic diversity of the colony.
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Affiliation(s)
- Carlos M. Aguero
- Department of EntomologyTexas A&M UniversityCollege StationTXUSA
| | | | - Jason S. Martin
- Department of Biological SciencesTowson UniversityTowsonMDUSA
| | - Mark S. Bulmer
- Department of Biological SciencesTowson UniversityTowsonMDUSA
| | - Edward L. Vargo
- Department of EntomologyTexas A&M UniversityCollege StationTXUSA
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7
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Cole EL, Empringham JS, Biro C, Thompson GJ, Rosengaus RB. Relish as a Candidate Marker for Transgenerational Immune Priming in a Dampwood Termite (Blattodae: Archeotermopsidae). INSECTS 2020; 11:E149. [PMID: 32120840 PMCID: PMC7143124 DOI: 10.3390/insects11030149] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/21/2020] [Accepted: 02/24/2020] [Indexed: 11/17/2022]
Abstract
Natural selection should favor the transfer of immune competence from one generation to the next in a context-dependent manner. Transgenerational immune priming (TGIP) is expected to evolve when species exploit pathogen-rich environments and exhibit extended overlap of parent-offspring generations. Dampwood termites are hemimetabolous, eusocial insects (Blattodea: Archeotermopsidae) that possess both of these traits. We predict that offspring of pathogen-exposed queens of Zootermopsis angusticollis will show evidence of a primed immune system relative to the offspring of unexposed controls. We found that Relish transcripts, one of two immune marker loci tested, were enhanced in two-day-old embryos when laid by Serratia-injected queens. These data implicate the immune deficiency (IMD) signaling pathway in TGIP. Although an independent antibacterial assay revealed that embryos do express antibacterial properties, these do not vary as a function of parental treatment. Taken together, Z. angusticollis shows transcriptional but not translational evidence for TGIP. This apparent incongruence between the transcriptional and antimicrobial response from termites suggests that effectors are either absent in two-day-old embryos or their activity is too subtle to detect with our antibacterial assay. In total, we provide the first suggestive evidence of transgenerational immune priming in a termite.
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Affiliation(s)
- Erin L. Cole
- Department of Marine and Environmental Sciences, Northeastern University, 134 Mugar Life Sciences Building, 360 Huntington Avenue, Boston, MA 02115, USA; (E.L.C.); (C.B.)
| | - Jessica S. Empringham
- Department of Biology, Western University, 1151 Richmond St. London, ON N6A 5B7, Canada; (J.S.E.); (G.J.T.)
| | - Colette Biro
- Department of Marine and Environmental Sciences, Northeastern University, 134 Mugar Life Sciences Building, 360 Huntington Avenue, Boston, MA 02115, USA; (E.L.C.); (C.B.)
| | - Graham J. Thompson
- Department of Biology, Western University, 1151 Richmond St. London, ON N6A 5B7, Canada; (J.S.E.); (G.J.T.)
| | - Rebeca B. Rosengaus
- Department of Marine and Environmental Sciences, Northeastern University, 134 Mugar Life Sciences Building, 360 Huntington Avenue, Boston, MA 02115, USA; (E.L.C.); (C.B.)
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Cole EL, Rosengaus RB. Pathogenic Dynamics During Colony Ontogeny Reinforce Potential Drivers of Termite Eusociality: Mate Assistance and Biparental Care. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00473] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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9
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Cole EL, Ilieş I, Rosengaus RB. Competing Physiological Demands During Incipient Colony Foundation in a Social Insect: Consequences of Pathogenic Stress. Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00103] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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10
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Colony-founding success of pleometrosis in a fungus-growing termite Odontotermes formosanus. Behav Ecol Sociobiol 2017. [DOI: 10.1007/s00265-017-2429-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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11
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Cooney F, Vitikainen EIK, Marshall HH, van Rooyen W, Smith RL, Cant MA, Goodey N. Lack of aggression and apparent altruism towards intruders in a primitive termite. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160682. [PMID: 28018658 PMCID: PMC5180156 DOI: 10.1098/rsos.160682] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 10/06/2016] [Indexed: 06/06/2023]
Abstract
In eusocial insects, the ability to discriminate nest-mates from non-nest-mates is widespread and ensures that altruistic actions are directed towards kin and agonistic actions are directed towards non-relatives. Most tests of nest-mate recognition have focused on hymenopterans, and suggest that cooperation typically evolves in tandem with strong antagonism towards non-nest-mates. Here, we present evidence from a phylogenetically and behaviourally basal termite species that workers discriminate members of foreign colonies. However, contrary to our expectations, foreign intruders were the recipients of more rather than less cooperative behaviour and were not subjected to elevated aggression. We suggest that relationships between groups may be much more peaceable in basal termites compared with eusocial hymenoptera, owing to energetic and temporal constraints on colony growth, and the reduced incentive that totipotent workers (who may inherit breeding status) have to contribute to self-sacrificial intergroup conflict.
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Affiliation(s)
- Feargus Cooney
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9EZ, UK
| | - Emma I. K. Vitikainen
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9EZ, UK
| | - Harry H. Marshall
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9EZ, UK
| | - Wilmie van Rooyen
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9EZ, UK
| | - Robert L. Smith
- Department of Entomology, University of Arizona, Forbes 410, Tucson, AZ 85721-0036, USA
| | - Michael A. Cant
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9EZ, UK
| | - Nicole Goodey
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9EZ, UK
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12
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Rosengaus RB, Reichheld JL. Phenoloxidase activity in the infraorder Isoptera: unraveling life-history correlates of immune investment. Naturwissenschaften 2016; 103:14. [PMID: 26838762 DOI: 10.1007/s00114-016-1338-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 01/19/2016] [Accepted: 01/21/2016] [Indexed: 11/25/2022]
Abstract
Within the area of ecological immunology, the quantification of phenoloxidase (PO) activity has been used as a proxy for estimating immune investment. Because termites have unique life-history traits and significant inter-specific differences exist regarding their nesting and foraging habits, comparative studies on PO activity can shed light on the general principles influencing immune investment against the backdrop of sociality, reproductive potential, and gender. We quantified PO activity across four termite species ranging from the phylogenetically basal to the most derived, each with their particular nesting/foraging strategies. Our data indicate that PO activity varies across species, with soil-dwelling termites exhibiting significantly higher PO levels than the above-ground wood nester species which in turn have higher PO levels than arboreal species. Moreover, our comparative approach suggests that pathogenic risks can override reproductive potential as a more important driver of immune investment. No gender-based differences in PO activities were recorded. Although termite PO activity levels vary in accordance with a priori predictions made from life-history theory, our data indicate that nesting and foraging strategies (and their resulting pathogenic pressures) can supersede reproductive potential and other life-history traits in influencing investment in PO. Termites, within the eusocial insects, provide a unique perspective for inferring how different ecological pressures may have influenced immune function in general and their levels of PO activity, in particular.
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Affiliation(s)
- Rebeca B Rosengaus
- Department of Marine and Environmental Sciences, Northeastern University, 134 Mugar Life Sciences Building, 360 Huntington Avenue, Boston, MA, 02115-5000, USA.
| | - Jennifer L Reichheld
- Department of Marine and Environmental Sciences, Northeastern University, 134 Mugar Life Sciences Building, 360 Huntington Avenue, Boston, MA, 02115-5000, USA
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Unrelated secondary reproductives in the neotropical termite Silvestritermes euamignathus (Isoptera: Termitidae). Naturwissenschaften 2016; 103:9. [PMID: 26781111 DOI: 10.1007/s00114-015-1325-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 12/14/2015] [Accepted: 12/18/2015] [Indexed: 10/22/2022]
Abstract
A termite colony is usually founded by a pair of alates, the primary reproductives, which produce all the nestmates. In some species, secondary reproductives appear to either replace the primaries or supplement colony reproduction. In termites, secondary reproductives are generally ergatoids derived from workers or nymphoids derived from nymphs. Silvestritermes euamignathus is a termite species that forms multiple nymphoid reproductives, and to date it was hypothesized that these secondary reproductives were the progeny of the primary founding reproductives. We developed markers for 12 microsatellite loci and used COI mitochondrial DNA (mtDNA) to genotype 59 nymphoid neotenics found in a colony of S. euamignathus to test this hypothesis. Our results showed that nymphoids of S. euamignathus are not all siblings. The microsatellite analysis suggests that the secondary reproductives derived from a minimum of four different pairs of reproductives belonging to at least two different matrilines. This is the first record of non-sibling secondary reproductives occupying the same nest in a higher termite. These unrelated reproductives might be the result of either pleometrotic colony foundation or colony fusion.
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Boomsma JJ, Huszár DB, Pedersen JS. The evolution of multiqueen breeding in eusocial lineages with permanent physically differentiated castes. Anim Behav 2014. [DOI: 10.1016/j.anbehav.2014.03.005] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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Pull CD, Hughes WOH, Brown MJF. Tolerating an infection: an indirect benefit of co-founding queen associations in the ant Lasius niger. Naturwissenschaften 2013; 100:1125-36. [DOI: 10.1007/s00114-013-1115-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 10/22/2013] [Accepted: 10/25/2013] [Indexed: 10/26/2022]
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