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Mikhailova AA, Dohmen E, Harrison MC. Major changes in domain arrangements are associated with the evolution of termites. J Evol Biol 2024; 37:758-769. [PMID: 38630634 DOI: 10.1093/jeb/voae047] [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: 05/31/2023] [Revised: 12/18/2023] [Accepted: 04/12/2024] [Indexed: 04/19/2024]
Abstract
Domains as functional protein units and their rearrangements along the phylogeny can shed light on the functional changes of proteomes associated with the evolution of complex traits like eusociality. This complex trait is associated with sterile soldiers and workers, and long-lived, highly fecund reproductives. Unlike in Hymenoptera (ants, bees, and wasps), the evolution of eusociality within Blattodea, where termites evolved from within cockroaches, was accompanied by a reduction in proteome size, raising the question of whether functional novelty was achieved with existing rather than novel proteins. To address this, we investigated the role of domain rearrangements during the evolution of termite eusociality. Analysing domain rearrangements in the proteomes of three solitary cockroaches and five eusocial termites, we inferred more than 5,000 rearrangements over the phylogeny of Blattodea. The 90 novel domain arrangements that emerged at the origin of termites were enriched for several functions related to longevity, such as protein homeostasis, DNA repair, mitochondrial activity, and nutrient sensing. Many domain rearrangements were related to changes in developmental pathways, important for the emergence of novel castes. Along with the elaboration of social complexity, including permanently sterile workers and larger, foraging colonies, we found 110 further domain arrangements with functions related to protein glycosylation and ion transport. We found an enrichment of caste-biased expression and splicing within rearranged genes, highlighting their importance for the evolution of castes. Furthermore, we found increased levels of DNA methylation among rearranged compared to non-rearranged genes suggesting fundamental differences in their regulation. Our findings indicate the importance of domain rearrangements in the generation of functional novelty necessary for termite eusociality to evolve.
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Affiliation(s)
- Alina A Mikhailova
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
| | - Elias Dohmen
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
| | - Mark C Harrison
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
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2
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Zhou Q, Yu T, Li W, Nasser R, Chidwala N, Mo J. Prostaglandin A3 regulates the colony development of Odontotermes formosanus by reducing worker proportion. CROP HEALTH 2024; 2:11. [PMID: 38984319 PMCID: PMC11232360 DOI: 10.1007/s44297-024-00030-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 06/11/2024] [Accepted: 06/12/2024] [Indexed: 07/11/2024]
Abstract
Subterranean termites cause significant economic losses worldwide due to their destruction of agricultural and forest plants. In the past, soil termiticides were commonly used to control subterranean termites because they were effective and affordable. However, due to growing environmental concerns, these harmful substances have become less popular as they cause damage to non-target organisms and lead to environmental contamination. Baits crafted from plants and other easily metabolized compounds serve as excellent alternatives. In this study, we gathered branches from the promising plant, Magnolia grandiflora L. (MGL), along with branches from five other tree species that are potential food for termites. These branches were used as food to observe the population growth of Odontotermes formosanus. Additionally, a mix of branches from all six species was used to feed the control group (MIX). The study results showed that MGL nutrition significantly inhibited worker development, resulting in a significantly lower worker-to-soldier ratio (WSR). Furthermore, LC‒MS/MS analysis revealed that the level of prostaglandin A3 (PGA3) in workers significantly increased when they were under MGL nutrition. Additionally, ICP-MS analysis indicated a significant increase in calcium concentrations in the branches of MGL and combs under MGL nutrition. Moreover, there was a significant increase in peroxidase (POD) activity in workers under MGL nutrition. These findings suggest that the inhibitory effect of MGL nutrition on worker development may be due to excessive PGA3 synthesis, as Ca2+ and POD are involved in the synthesis process of PGs in insects. Subsequent verification experiments strongly support this hypothesis, as the WSR of colonies fed PGA3-added MIX was significantly lower than that of the MIX alone. This study introduces a new concept for developing environmentally friendly biological control methods for O. formosanus and sheds light on the potential role of PGs in termite development. Supplementary Information The online version contains supplementary material available at 10.1007/s44297-024-00030-3.
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Affiliation(s)
- Qihuan Zhou
- Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058 China
| | - Ting Yu
- Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058 China
| | - Wuhan Li
- Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058 China
| | - Raghda Nasser
- Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058 China
- Department of Zoology and Entomology, Faculty of Science, Minia University, El-Minia, 61519 Egypt
| | - Nooney Chidwala
- Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058 China
| | - Jianchu Mo
- Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058 China
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3
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Erezyilmaz D. The genetic determination of alternate stages in polyphenic insects. Evol Dev 2024:e12485. [PMID: 38867484 DOI: 10.1111/ede.12485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/23/2024] [Accepted: 05/14/2024] [Indexed: 06/14/2024]
Abstract
Molt-based transitions in form are a central feature of insect life that have enabled adaptation to diverse and changing environments. The endocrine regulation of these transitions is well established, but an understanding of their genetic regulation has only recently emerged from insect models. The pupal and adult stages of metamorphosing insects are determined by the stage specifying transcription factors broad-complex (br) and Ecdysone inducible protein 93 (E93), respectively. A probable larval determinant, chronologically inappropriate metamorphosis (chinmo), has just recently been characterized. Expression of these three transcription factors in the metamorphosing insects is regulated by juvenile hormone with ecdysteroid hormones, and by mutual repression between the stage-specific transcription factors. This review explores the hypothesis that variations in the onset, duration, and tissue-specific expression of chinmo, br, and E93 underlie other polyphenisms that have arisen throughout insects, including the castes of social insects, aquatic stages of mayflies, and the neoteny of endoparasites. The mechanisms that constrain how chinmo, br, and E93 expression may vary will also constrain the ways that insect life history may evolve. I find that four types of expression changes are associated with novel insect forms: (1) heterochronic shift in the turnover of expression, (2) expansion or contraction of expression, (3) tissue-specific expression, and (4) redeployment of stage-specific expression. While there is more to be learned about chinmo, br, and E93 function in diverse insect taxa, the studies outlined here show that insect stages are modular units in developmental time and a substrate for evolutionary forces to act upon.
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Affiliation(s)
- Deniz Erezyilmaz
- Department of Physiology, Anatomy and Genetics, Centre for Neural Circuits and Behavior, University of Oxford, Oxford, UK
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Revely L, Eggleton P, Clement R, Zhou C, Bishop TR. The diversity of social complexity in termites. Proc Biol Sci 2024; 291:20232791. [PMID: 38835273 DOI: 10.1098/rspb.2023.2791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 05/03/2024] [Indexed: 06/06/2024] Open
Abstract
Sociality underpins major evolutionary transitions and significantly influences the structure and function of complex ecosystems. Social insects, seen as the pinnacle of sociality, have traits like obligate sterility that are considered 'master traits', used as single phenotypic measures of this complexity. However, evidence is mounting that completely aligning both phenotypic and evolutionary social complexity, and having obligate sterility central to both, is erroneous. We hypothesize that obligate and functional sterility are insufficient in explaining the diversity of phenotypic social complexity in social insects. To test this, we explore the relative importance of these sterility traits in an understudied but diverse taxon: the termites. We compile the largest termite social complexity dataset to date, using specimen and literature data. We find that although functional and obligate sterility explain a significant proportion of variance, neither trait is an adequate singular proxy for the phenotypic social complexity of termites. Further, we show both traits have only a weak association with the other social complexity traits within termites. These findings have ramifications for our general comprehension of the frameworks of phenotypic and evolutionary social complexity, and their relationship with sterility.
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Affiliation(s)
- Lewis Revely
- Soil Biodiversity Group, Department of Life Sciences, The Natural History Museum, London SW7 5BD, UK
- Centre for Biodiversity and Environmental Research, Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Paul Eggleton
- Soil Biodiversity Group, Department of Life Sciences, The Natural History Museum, London SW7 5BD, UK
| | - Rebecca Clement
- Computational Biology Institute, George Washington University, Washington, DC 20052, USA
| | - Chuanyu Zhou
- Soil Biodiversity Group, Department of Life Sciences, The Natural History Museum, London SW7 5BD, UK
| | - Tom R Bishop
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
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Oguchi K, Miura T. Body part-specific development in termite caste differentiation: crosstalk between hormonal actions and developmental toolkit genes. CURRENT OPINION IN INSECT SCIENCE 2024; 63:101183. [PMID: 38428818 DOI: 10.1016/j.cois.2024.101183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 02/24/2024] [Accepted: 02/25/2024] [Indexed: 03/03/2024]
Abstract
In social insects, interactions among colony members trigger caste differentiation with morphological modifications. During caste differentiation in termites, body parts and caste-specific morphologies are modified during postembryonic development under endocrine controls such as juvenile hormone (JH) and ecdysone. In addition to endocrine factors, developmental toolkit genes such as Hox- and appendage-patterning genes also contribute to the caste-specific body part modifications. These toolkits are thought to provide spatial information for specific morphogenesis. During social evolution, the complex crosstalks between physiological and developmental mechanisms should be established, leading to the sophisticated caste systems. This article reviews recent studies on these mechanisms underlying the termite caste differentiation and addresses implications for the evolution of caste systems in termites.
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Affiliation(s)
- Kohei Oguchi
- Misaki Marine Biological Station, The University of Tokyo, Miura, Kanagawa 238-0225, Japan
| | - Toru Miura
- Misaki Marine Biological Station, The University of Tokyo, Miura, Kanagawa 238-0225, Japan.
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Du H, Huang R, Chen DS, Zhuang T, Huang X, Zhang H, Li Z. Regulation of soldier caste differentiation by microRNAs in Formosan subterranean termite ( Coptotermes formosanus Shiraki). PeerJ 2024; 12:e16843. [PMID: 38436016 PMCID: PMC10909360 DOI: 10.7717/peerj.16843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 01/05/2024] [Indexed: 03/05/2024] Open
Abstract
The soldier caste is one of the most distinguished castes inside the termite colony. The mechanism of soldier caste differentiation has mainly been studied at the transcriptional level, but the function of microRNAs (miRNAs) in soldier caste differentiation is seldom studied. In this study, the workers of Coptotermes formosanus Shiraki were treated with methoprene, a juvenile hormone analog which can induce workers to transform into soldiers. The miRNomes of the methoprene-treated workers and the controls were sequenced. Then, the differentially expressed miRNAs (DEmiRs) were corrected with the differentially expressed genes DEGs to construct the DEmiR-DEG regulatory network. Afterwards, the DEmiR-regulated DEGs were subjected to GO enrichment and KEGG enrichment analysis. A total of 1,324 miRNAs were identified, among which 116 miRNAs were screened as DEmiRs between the methoprene-treated group and the control group. A total of 4,433 DEmiR-DEG pairs were obtained. No GO term was recognized as significant in the cellular component, molecular function, or biological process categories. The KEGG enrichment analysis of the DEmiR-regulated DEGs showed that the ribosome biogenesis in eukaryotes and circadian rhythm-fly pathways were enriched. This study demonstrates that DEmiRs and DEGs form a complex network regulating soldier caste differentiation in termites.
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Affiliation(s)
- He Du
- Guangdong Key Laboratory of Integrated Pest Management in Agriculture, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou, China
| | - Runmei Huang
- Guangdong Key Laboratory of Integrated Pest Management in Agriculture, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou, China
| | - Da-Song Chen
- Guangdong Key Laboratory of Integrated Pest Management in Agriculture, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou, China
| | - Tianyong Zhuang
- Guangdong Key Laboratory of Integrated Pest Management in Agriculture, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou, China
| | - Xueyi Huang
- Guangdong Key Laboratory of Integrated Pest Management in Agriculture, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou, China
| | - Huan Zhang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Zhiqiang Li
- Guangdong Key Laboratory of Integrated Pest Management in Agriculture, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou, China
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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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Liu F, Yu S, Chen N, Ren C, Li S. Nutrition- and hormone-controlled developmental plasticity in Blattodea. CURRENT OPINION IN INSECT SCIENCE 2023; 60:101128. [PMID: 37806339 DOI: 10.1016/j.cois.2023.101128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 09/12/2023] [Accepted: 10/02/2023] [Indexed: 10/10/2023]
Abstract
Blattodea, which includes cockroaches and termites, possesses high developmental plasticity that is mainly controlled by nutritional conditions and insect hormones. Insulin/insulin-like growth factor signaling (IIS), target of rapamycin complex 1 (TORC1), and adenosine monophosphate-activated protein complex are the three primary nutrition-responsive signals. Juvenile hormone (JH) and 20-hydroxyecdysone (20E) constitute the two most vital insect hormones that might interact with each other through the Met, Kr-h1, E93 (MEKRE93) pathway. Nutritional and hormonal signals interconnect to create a complex regulatory network. Here we summarize recent progress in our understanding of how nutritional and hormonal signals coordinately control the developmental plasticity of metamorphosis, reproduction, and appendage regeneration in cockroaches as well as caste differentiation in termites. We also highlight several perspectives that should be further emphasized in the studies of developmental plasticity in Blattodea. This review provides a general landscape in the field of nutrition- and hormone-controlled developmental plasticity in insects.
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Affiliation(s)
- Fangfang Liu
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China; Guangmeiyuan R&D Center, Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, South China Normal University, Meizhou 514779, China
| | - Shuxin Yu
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Nan Chen
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Chonghua Ren
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Sheng Li
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China; Guangmeiyuan R&D Center, Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, South China Normal University, Meizhou 514779, China.
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Salazar-Salazar LR, Pinzón-Florian OP. Ecology, behavior and bionomics: functional response of Heterotermes tenuis Hagen (Insecta: Blattaria: Isoptera: Rhinotermitidae) in forests of the Colombian Orinoquía. BMC ZOOL 2023; 8:24. [PMID: 37884987 PMCID: PMC10601117 DOI: 10.1186/s40850-023-00184-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 09/06/2023] [Indexed: 10/28/2023] Open
Abstract
BACKGROUND Land use intensification may affect diversity, abundance, and functional morphological traits (FMT) related to dispersal, food acquisition, digestion, and nesting in some insects, possibly impacting their ecological role. Most studies of termites on the effects of afforestation focus on diversity and abundance, but changes in FMT have yet to be studied. AIM To better understand the response mechanisms to land use intensification, we compared the FMT of the worker and soldier caste of Heterotermes tenuis among Pinus caribaea plantations of four different ages and gallery forests of the Colombian Orinoquía. METHODOLOGY We measured thirty-eight FMTs in the worker and soldier castes of H. tenuis from gallery forests and pine plantations. Then, we used a Community-Weighted Mean (CWM), a PERMANOVA, and a nonmetric multidimensional scaling (NMDS) to estimate the possible effect of land use type on the FMT of both castes. We selected the FMTs with the lowest intraspecific coefficient of variation (CV) from each caste to compare their size among the land use types and pine plantation ages. RESULTS Land use type had a more significant impact on the FMT size of pine plantation workers than the age of the afforestation. FMT of the worker caste tends to be larger in gallery forests than in pine plantations, while the results were inconclusive for soldiers. CONCLUSION The results suggested a homogenization mainly of the feeding FMT of the worker caste of H. tenuis in pine plantations associated with the increase in the softwood food resource of P. caribaea.
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Oguchi K, Miura T. Upregulation of Hox genes leading to caste-specific morphogenesis in a termite. EvoDevo 2023; 14:12. [PMID: 37501210 PMCID: PMC10375622 DOI: 10.1186/s13227-023-00216-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 07/13/2023] [Indexed: 07/29/2023] Open
Abstract
BACKGROUND In social insects, interactions among colony members trigger caste differentiation with morphological modifications. In termite caste differentiation, caste-specific morphologies (such as mandibles in soldiers, genital organs in reproductives or wings in alates) are well developed during post-embryonic development under endocrine controls (e.g., juvenile hormone and ecdysone). Since body part-specific morphogenesis in caste differentiation is hormonally regulated by global factors circulated throughout the body, positional information should be required for the caste-specific and also body part-specific morphogenesis. To identify factors providing the positional information, expression and functional analyses of eight Hox genes were carried out during the three types of caste differentiation (i.e., soldier, neotenic and alate differentiation) in a termite, Hodotermopsis sjostedti. RESULTS Spatio-temporal patterns of Hox gene expression during caste differentiation were elucidated by real-time qPCR, showing the caste-specific upregulations of Hox genes during the differentiation processes. Among eight Hox genes, Deformed (Dfd) was upregulated specifically in mandibles in soldier differentiation, abdominal-A (abd-A) and Abdominal-B (Abd-B) were upregulated in the abdomen in neotenic differentiation, while Sex-comb reduced (Scr) and Antennapedia (Antp) were upregulated during alate differentiation. Furthermore, RNAi knockdown of Dfd in soldier differentiation and of abd-A and Abd-B in neotenic differentiation distorted the modifications of caste-specific morphologies. CONCLUSIONS Gene expression and functional analyses in this study revealed that, in the caste differentiation in termites, upregulation of Hox genes provide positional identities of body segments, resulting in the caste-specific morphogenesis. The acquisition of such developmental modifications would have enabled the evolution of sophisticated caste systems in termites.
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Affiliation(s)
- Kohei Oguchi
- Misaki Marine Biological Station, Graduate School of Science, The University of Tokyo, Miura, Kanagawa, 238-0225, Japan.
| | - Toru Miura
- Misaki Marine Biological Station, Graduate School of Science, The University of Tokyo, Miura, Kanagawa, 238-0225, Japan
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Rau V, Flatt T, Korb J. The remoulding of dietary effects on the fecundity / longevity trade-off in a social insect. BMC Genomics 2023; 24:244. [PMID: 37147612 PMCID: PMC10163710 DOI: 10.1186/s12864-023-09335-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 04/25/2023] [Indexed: 05/07/2023] Open
Abstract
BACKGROUND In many organisms increased reproductive effort is associated with a shortened life span. This trade-off is reflected in conserved molecular pathways that link nutrient-sensing with fecundity and longevity. Social insect queens apparently defy the fecundity / longevity trade-off as they are both, extremely long-lived and highly fecund. Here, we have examined the effects of a protein-enriched diet on these life-history traits and on tissue-specific gene expression in a termite species of low social complexity. RESULTS On a colony level, we did not observe reduced lifespan and increased fecundity, effects typically seen in solitary model organisms, after protein enrichment. Instead, on the individual level mortality was reduced in queens that consumed more of the protein-enriched diet - and partially also in workers - while fecundity seemed unaffected. Our transcriptome analyses supported our life-history results. Consistent with life span extension, the expression of IIS (insulin/insulin-like growth factor 1 signalling) components was reduced in fat bodies after protein enrichment. Interestingly, however, genes involved in reproductive physiology (e.g., vitellogenin) were largely unaffected in fat body and head transcriptomes. CONCLUSION These results suggest that IIS is decoupled from downstream fecundity-associated pathways, which can contribute to the remoulding of the fecundity/longevity trade-off in termites as compared to solitary insects.
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Affiliation(s)
- Veronika Rau
- Evolutionary Biology & Ecology, University of Freiburg, Hauptstrasse 1, 79104, Freiburg (Brsg.), Germany.
| | - Thomas Flatt
- Department of Biology, University of Fribourg, Chemin du Musée 10, CH-1700, Fribourg, Switzerland
| | - Judith Korb
- Evolutionary Biology & Ecology, University of Freiburg, Hauptstrasse 1, 79104, Freiburg (Brsg.), Germany.
- RIEL, Charles Darwin University Casuarina Campus, Ellengowan Drive, Darwin, NT0811, Australia.
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Martelossi J, Forni G, Iannello M, Savojardo C, Martelli PL, Casadio R, Mantovani B, Luchetti A, Rota-Stabelli O. Wood feeding and social living: Draft genome of the subterranean termite Reticulitermes lucifugus (Blattodea; Termitoidae). INSECT MOLECULAR BIOLOGY 2023; 32:118-131. [PMID: 36366787 DOI: 10.1111/imb.12818] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 11/08/2022] [Indexed: 06/16/2023]
Abstract
Termites (Insecta, Blattodea, Termitoidae) are a widespread and diverse group of eusocial insects known for their ability to digest wood matter. Herein, we report the draft genome of the subterranean termite Reticulitermes lucifugus, an economically important species and among the most studied taxa with respect to eusocial organization and mating system. The final assembly (~813 Mb) covered up to 88% of the estimated genome size and, in agreement with the Asexual Queen Succession Mating System, it was found completely homozygous. We predicted 16,349 highly supported gene models and 42% of repetitive DNA content. Transposable elements of R. lucifugus show similar evolutionary dynamics compared to that of other termites, with two main peaks of activity localized at 25% and 8% of Kimura divergence driven by DNA, LINE and SINE elements. Gene family turnover analyses identified multiple instances of gene duplication associated with R. lucifugus diversification, with significant lineage-specific gene family expansions related to development, perception and nutrient metabolism pathways. Finally, we analysed P450 and odourant receptor gene repertoires in detail, highlighting the large diversity and dynamical evolutionary history of these proteins in the R. lucifugus genome. This newly assembled genome will provide a valuable resource for further understanding the molecular basis of termites biology as well as for pest control.
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Affiliation(s)
- Jacopo Martelossi
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy
| | - Giobbe Forni
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy
- Dipartimento di Scienze Agrarie e Ambientali, Università degli Studi di Milano, Milano, Italy
| | - Mariangela Iannello
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy
| | - Castrense Savojardo
- Biocomputing Group, Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Pier Luigi Martelli
- Biocomputing Group, Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Rita Casadio
- Biocomputing Group, Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Barbara Mantovani
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy
| | - Andrea Luchetti
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy
| | - Omar Rota-Stabelli
- Center Agriculture Food Environment C3A, University of Trento/Fondazione Edmund Mach, Trento, Italy
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Wu J, Wang J, Wang Y, Hassan A. Same-sex Pairs Retain Their Reproductive Capacity as a Potential Opportunity for Individual Reproductive Success in Termites. JOURNAL OF INSECT SCIENCE (ONLINE) 2023; 23:9. [PMID: 36757064 PMCID: PMC9909647 DOI: 10.1093/jisesa/ieac073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Indexed: 06/18/2023]
Abstract
In eusocial termites, successful pairing is an essential element of dispersal and distribution after the departure of alates from natal colonies. Two situations could arise during the pairing process: mixed-sex pairs and same-sex pairs. However, most previous studies focused on mixed-sex pairs, overlooking groups formed by same-sex pairings, especially potential fecundity (the total number of oocytes or ovarioles), oogenesis and the development stage of oocytes of females in female-female pairs, and spermatogenesis and testis development of males in male-male pairs. In this study, through experimentation, we investigated the reproductive ability of virgin dealates based on various pairing types as mentioned above. We found that the life spans of virgin dealates can cover 1 yr or even more when they establish a nest with a partner, which is more than 10-fold longer than the life span of individuals establishing a colony alone. After 1 yr of pairing, the potential fecundity of virgin same sex dealates did not degenerate significantly compared with newly emerged dealates, including the number of ovarioles, size of testis, oogenesis, and the development stage of the oocytes. Moreover, when individuals of same-sex pairings experimentally changed into mixed-sex pairs after 1 yr, the eggs produced in the colony hatched into larvae. These findings suggest that dealates which through same-sex pairs retain fecundity after 1 yr have more reproductive potential than dealates that failed to pair with heterosexuals, shedding light on the ecological significance of homosexual behaviors in terms of the successful extension and fecundity of eusocial termites.
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Affiliation(s)
- Jia Wu
- Applied Research Center for Life Science, Xi’an International University, Xi’an, Shaanxi 710077, China
- College of Medicine, Xi’an International University, Xi’an, Shaanxi 710077, China
| | | | - Yonghui Wang
- College of Engineering, Xi’an International University, Xi’an, Shaanxi 710077, China
| | - Ali Hassan
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan 430070, Hubei, China
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Saba NU, Ye C, Zhang W, Wu T, Wang Y, Zhang X, Song Z, Xing L, Su X. The Antennal Sensilla and Expression Patterns of Olfactory Genes in the Lower Termite Reticulitermes aculabialis (Isoptera: Rhinotermitidae). JOURNAL OF INSECT SCIENCE (ONLINE) 2022; 22:11. [PMID: 36001302 PMCID: PMC9400615 DOI: 10.1093/jisesa/ieac045] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Indexed: 06/15/2023]
Abstract
The insect olfactory system plays pivotal roles in insect survival and reproduction through odor detection. Morphological and physiological adaptations are caste-specific and evolved independently in workers, soldiers, and reproductives in termites. However, it is unclear whether the olfactory system is involved in the division of labor in termite colonies. In the present study, the antennal sensilla of alates, workers, soldiers, nymphs, and larvae of the termite Reticulitermes aculabialis Tsai et Hwang ( Isoptera: Rhinotermitidae) were investigated. Transcriptomes were used to detect olfactory genes, and differential expression levels of olfactory genes were confirmed in various castes by qRT-PCR analysis. Nine types of sensilla were identified on the antennae of R. aculabialis, and soldiers possessed all 9 types. In 89,475 assembled unigenes, we found 16 olfactory genes, including 6 chemosensory protein (CSP) and 10 odorant-binding protein (OBP) genes. These OBP genes included 8 general odorant-binding protein genes (GOBPs) and 2 pheromone-binding protein-related protein (PBP) genes. Five CSP genes were more highly expressed in alates than in workers, soldiers, larvae, and nymphs, and the expression levels of CSP6 were significantly higher in nymphs. Seven GOBP and two PBP genes exhibited significantly higher expression levels in alates, and there were no significant differences in the expression levels of GOBP2 among workers, soldiers, alates, and larvae. These results suggest that alates, as primary reproductives, have unique expression patterns of olfactory genes, which play key roles in nuptial flight, mate seeking, and new colony foundation.
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Affiliation(s)
| | | | - Wenxiu Zhang
- College of Life Sciences, Northwest University, Xi’an, China
| | - Taoyu Wu
- College of Life Sciences, Northwest University, Xi’an, China
| | - Yijie Wang
- College of Life Sciences, Northwest University, Xi’an, China
| | - Xiaohan Zhang
- College of Life Sciences, Northwest University, Xi’an, China
| | - Zhuanzhuan Song
- College of Life Sciences, Northwest University, Xi’an, China
| | - Lianxi Xing
- College of Life Sciences, Northwest University, Xi’an, China
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15
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Aguilera-Olivares D, Torres-Guzmán B, Arab A, Flores-Prado L, Niemeyer HM. Body Size and Symmetry Properties of Termite Soldiers Under Two Intraspecific Competition Scenarios. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.882357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Single-piece nesting termites live and forage in the same piece of wood throughout their life, which limit their colony size. In certain species, more than one colony thrive in a given piece of wood (multicolonial substrate) and intraspecific competition become important in this limited resource, as has been reported in Zootermopsis nevadensis (Hagen, 1858) and Neotermes chilensis (Blattodea: Kalotermitidae) (Blanchard, 1851). The effects of such competition have been described mainly at population and colony levels rather than at the individual level. In eusocial insects such as termites, intraspecific competition constitutes a stress factor imposed to a colony as a whole and should also cause developmental instability in soldiers produced under such conditions. Investment in the production of soldiers involves a trade-off between colony maintenance costs and defense benefits. Hence, we hypothesize that body size and fluctuating asymmetry, two indicators of developmental instability, will increase when two or more colonies of N. chilensis share a piece of wood (high intraspecific competition scenario). Our results showed that soldiers developing in multicolonial substrates were indeed larger and more asymmetric than soldiers developing in unicolonial substrates. The large body size in a soldier could improve its chance to win a physical contest with a non-nestmate opponent; thus, despite the high cost to produce large soldiers in small colonies, larger soldier production could be an adaptative strategy to avoid being outcompeted. However, the effects of deviations from perfect symmetry on soldier performance are not clear.
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16
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Soldier Caste-Specific Protein 1 Is Involved in Soldier Differentiation in Termite Reticulitermes aculabialis. INSECTS 2022; 13:insects13060502. [PMID: 35735839 PMCID: PMC9224846 DOI: 10.3390/insects13060502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 05/22/2022] [Accepted: 05/23/2022] [Indexed: 01/27/2023]
Abstract
Termite soldiers are a unique caste among social insects, and their differentiation can be induced by Juvenile hormone (JH) from workers through two molts (worker–presoldier–soldier). However, the molecular mechanism underlying the worker-to-soldier transformation in termites is poorly understood. To explore the mechanism of soldier differentiation induced by JH, the gene soldier caste-specific protein 1 (RaSsp1, NCBI accession no: MT861054.1) in R. aculabialis was cloned, and its function was studied. This gene was highly expressed in the soldier caste, and the protein RsSsp1 was similar to the JHBP (JH-binding protein) domain-containing protein by Predict Protein online. In addition, JHIII could be anchored in the hydrophobic cage of RaSsp1 as the epoxide of the JHBP-bound JH according to the protein ligand molecular docking online tool AutoDock. The functional studies indicated that knocking down of the RaSsp1 shorted the presoldier’s head capsule, reduced mandible size, delayed molting time and decreased molting rate (from worker to presoldier) at the beginning of worker gut-purging. Furthermore, knocking down of the RaSsp1 had a more pronounced effect on soldier differentiation (from presoldier to soldier), and manifested in significantly shorter mandibles, rounder head capsules, and lower molting rate (from worker to presoldier) at the beginning of presoldier gut-purging. Correspondingly, the expressions of JH receptor Methoprene-tolerant (Met), the JH-inducible transcription factor Krüppel homolog1 (Kr-h1) and ecdysone signal genes Broad-complex (Br-C) were downregulated when knocking down the RaSsp1 at the above two stages. All these results that RaSsp1 may be involved in soldier differentiation from workers by binding and transporting JH.
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17
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Bai ZD, Shi CY, Sillam-Dussès D, Wang RW. Elusive workers are more likely to differentiate into replacement reproductives than aggressive workers in a lower termite. Curr Zool 2022. [DOI: 10.1093/cz/zoac040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
One of the most intriguing questions in eusocial insects is to understand how the overt reproductive conflict in the colony appears limited when queens or kings are senescent or lost, since the morphologically similar individuals in the colony are reproductively totipotent. Whether there are some individuals which preferentially differentiate into replacement reproductives or not has received little attention. The consistent individual behavioral differences (also termed ‘animal personality’) of individuals from the colony can shape cunningly their task and consequently affect the colony fitness but have been rarely investigated in eusocial insects. Here, we used the termite Reticulitermes labralis to investigate if variations in individual personalities (elusiveness and aggressiveness) may predict which individuals will perform reproductive differentiation within colonies. We observed that when we separately reared elusive and aggressive workers, elusive workers differentiate into reproductives significantly earlier than aggressive workers. When we reared them together in the proportions 12:3, 10:5 and 8:7 (aggressive workers:elusive workers), the first reproductives mostly differentiated from the elusive workers, and the reproductives differentiated from the elusive workers significantly earlier than from aggressive workers. Furthermore, we found that the number of workers participating in reproductive differentiation was significantly lower in the groups of both type of workers than in groups containing only elusive workers. Our results demonstrate that the elusiveness trait was a strong predictor of workers differentiation into replacement reproductives in R. labralis. Moreover, our results suggest that individual personalities within the insect society could play a key role in resolving the overt reproductive conflict.
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Affiliation(s)
- Zhuang-Dong Bai
- School of Ecology and Environment, Northwestern Polytechnical University, Xi’an 710072, China
| | - Chong-Yang Shi
- School of Ecology and Environment, Northwestern Polytechnical University, Xi’an 710072, China
| | - David Sillam-Dussès
- Laboratory of Experimental and Comparative Ethology, LEEC, UR 4443, University Sorbonne Paris Nord, Villetaneuse, France
| | - Rui-Wu Wang
- School of Ecology and Environment, Northwestern Polytechnical University, Xi’an 710072, China
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18
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Castillo P, Husseneder C, Sun Q. Molecular characterization and expression variation of the odorant receptor co-receptor in the Formosan subterranean termite. PLoS One 2022; 17:e0267841. [PMID: 35482814 PMCID: PMC9049313 DOI: 10.1371/journal.pone.0267841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 04/14/2022] [Indexed: 11/18/2022] Open
Abstract
Subterranean termites live in underground colonies with a division of labor among castes (i.e., queens and kings, workers, and soldiers). The function of social colonies relies on sophisticated chemical communication. Olfaction, the sense of smell from food, pathogens, and colony members, plays an important role in their social life. Olfactory plasticity in insects can be induced by long- and short-term environmental perturbations, allowing adaptive responses to the chemical environment according to their physiological and behavioral state. However, there is a paucity of information on the molecular basis of olfaction in termites. In this study, we identified an ortholog encoding the odorant receptor co-receptor (Orco) in the Formosan subterranean termite, Coptotermes formosanus, and examined its expression variation across developmental stages and in response to social conditions. We found that C. formosanus Orco showed conserved sequence and structure compared with other insects. Spatial and temporal analyses showed that the Orco gene was primarily expressed in the antennae, and it was expressed in eggs and all postembryonic developmental stages. The antennal expression of Orco was upregulated in alates (winged reproductives) compared with workers and soldiers. Further, the expression of Orco decreased in workers after starvation for seven days, but it was not affected by the absence of soldiers or different group sizes. Our study reveals the molecular characteristics of Orco in a termite, and the results suggest a link between olfactory sensitivity and nutritional status. Further studies are warranted to better understand the role of Orco in olfactory plasticity and behavioral response.
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Affiliation(s)
- Paula Castillo
- Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, United States of America
| | - Claudia Husseneder
- Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, United States of America
| | - Qian Sun
- Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, United States of America
- * E-mail:
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19
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Oguchi K, Koshikawa S, Miura T. Hormone-related genes heterochronically and modularly regulate neotenic differentiation in termites. Dev Biol 2022; 485:70-79. [DOI: 10.1016/j.ydbio.2022.02.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 02/22/2022] [Accepted: 02/26/2022] [Indexed: 11/26/2022]
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20
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Mizumoto N, Bourguignon T. The evolution of body size in termites. Proc Biol Sci 2021; 288:20211458. [PMID: 34784763 PMCID: PMC8596001 DOI: 10.1098/rspb.2021.1458] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 10/27/2021] [Indexed: 12/17/2022] Open
Abstract
Termites are social cockroaches. Because non-termite cockroaches are larger than basal termite lineages, which themselves include large termite species, it has been proposed that termites experienced a unidirectional body size reduction since they evolved eusociality. However, the validity of this hypothesis remains untested in a phylogenetic framework. Here, we reconstructed termite body size evolution using head width measurements of 1638 modern and fossil termite species. We found that the unidirectional body size reduction model was only supported by analyses excluding fossil species. Analyses including fossil species suggested that body size diversified along with speciation events and estimated that the size of the common ancestor of modern termites was comparable to that of modern species. Our analyses further revealed that body size variability among species, but not body size reduction, is associated with features attributed to advanced termite societies. Our results suggest that miniaturization took place at the origin of termites, while subsequent complexification of termite societies did not lead to further body size reduction.
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Affiliation(s)
- Nobuaki Mizumoto
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan
| | - Thomas Bourguignon
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan
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21
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Bernadou A, Kramer BH, Korb J. Major Evolutionary Transitions in Social Insects, the Importance of Worker Sterility and Life History Trade-Offs. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.732907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The evolution of eusociality in social insects, such as termites, ants, and some bees and wasps, has been regarded as a major evolutionary transition (MET). Yet, there is some debate whether all species qualify. Here, we argue that worker sterility is a decisive criterion to determine whether species have passed a MET (= superorganisms), or not. When workers are sterile, reproductive interests align among group members as individual fitness is transferred to the colony level. Division of labour among cooperating units is a major driver that favours the evolution of METs across all biological scales. Many METs are characterised by a differentiation into reproductive versus maintenance functions. In social insects, the queen specialises on reproduction while workers take over maintenance functions such as food provisioning. Such division of labour allows specialisation and it reshapes life history trade-offs among cooperating units. For instance, individuals within colonies of social insects can overcome the omnipresent fecundity/longevity trade-off, which limits reproductive success in organisms, when increased fecundity shortens lifespan. Social insect queens (particularly in superorganismal species) can reach adult lifespans of several decades and are among the most fecund terrestrial animals. The resulting enormous reproductive output may contribute to explain why some genera of social insects became so successful. Indeed, superorganismal ant lineages have more species than those that have not passed a MET. We conclude that the release from life history constraints at the individual level is a important, yet understudied, factor across METs to explain their evolutionary success.
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22
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O'Donnell S, Bulova S, Barrett M. Experience-expectant brain plasticity corresponds to caste-specific abiotic challenges in dampwood termites (Zootermopsis angusticollis and Z. nevadensis). Naturwissenschaften 2021; 108:57. [PMID: 34665344 DOI: 10.1007/s00114-021-01763-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 09/21/2021] [Accepted: 09/22/2021] [Indexed: 02/03/2023]
Abstract
Hypotheses for adaptive brain investment predict associations between the relative sizes of functionally distinct brain regions and the sensory/cognitive demands animals confront. We measured developmental differences in the relative sizes of visual processing brain regions (optic lobes) among dampwood termite castes to test whether optic lobe investment matches caste differences in exposure to visually complex environments. The winged primary reproductives (Kings/Queens) on mating flights are the only caste to leave the dark nest cavities and as predicted, Kings/Queens showed greater relative investment in optic lobe tissue than nestbound (neotenic) reproductives and soldiers in two dampwood termite species (Zootermopsis angusticollis and Z. nevadensis). Relative optic lobe size spanned more than an order of magnitude among the castes we studied, suggesting the growth of the optic lobes incurs substantial tissue costs. Optic lobe growth was experience-expectant: the optic lobes of Z. angusticollis brachypterous nymphs, which typically develop into Kings/Queens, were relatively larger than the optic lobes of apterous nymphs, which precede neotenics and soldiers, and relative optic lobe size of nestbound brachypterous nymphs was statistically similar to that of Kings/Queens. Experience-expectant brain tissue growth is rarely documented in insects, likely because it entails high potential costs of tissue production and maintenance and relatively low immediate sensory/cognitive benefits. We develop hypotheses for the conditions under which experience-expectant growth in brain regions could be favored by natural selection.
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Affiliation(s)
- Sean O'Donnell
- Departments of Biodiversity Earth & Environmental Science and Biology, Drexel University, Philadelphia, PA, 19081, USA.
| | - Susan Bulova
- Departments of Biodiversity Earth & Environmental Science and Biology, Drexel University, Philadelphia, PA, 19081, USA
| | - Meghan Barrett
- Departments of Biodiversity Earth & Environmental Science and Biology, Drexel University, Philadelphia, PA, 19081, USA
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23
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Miyaguni Y, Agarie A, Sugio K, Tsuji K, Kobayashi K. Caste development and sex ratio of the Ryukyu drywood termite Neotermes sugioi and its potential mechanisms. Sci Rep 2021; 11:15037. [PMID: 34294796 PMCID: PMC8298410 DOI: 10.1038/s41598-021-94505-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 07/05/2021] [Indexed: 02/06/2023] Open
Abstract
Sex allocation is one of the most studied traits in evolutionary biology because its theoretical predictions match the empirical data. Here, using the Ryukyu dry-wood termite Neotermes sugioi, we investigated several factors that could bias the sex allocation in three populations (Okinawa, Ishigaki/Iriomote, and Yonaguni). Our survey showed that there were more queen-only colonies than king-only colonies in these populations, suggesting a longer lifespan of the queens than that of the kings. In this condition, sex-asymmetric reproductive value (SRV) theory predicts female bias, because even after the short-lived kings die, the long-lived queens can continue reproduction with their sons. However, sex allocation in this species seemed to be biased toward males. Furthermore, we examined the possibility of intrasexual competition among siblings (ICS). If ICS is the cause of the bias, the allocation is expected to change depending on the total investment in sexual offspring. However, the biomass of both male and female alates increased linearly with the increase in the total biomass of the alates in these populations. Thus, neither the SRV nor the ICS theory could explain the male-biased sex ratio of N. sugioi. On the basis of these results, we discuss the remaining possibilities in this species.
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Affiliation(s)
- Y Miyaguni
- Global Education Institute, University of the Ryukyus, Okinawa, 903-0213, Japan
| | - A Agarie
- Department of Environmental Science and Conservation Biology, United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, 890-8580, Japan
| | - K Sugio
- Graduate School of Education, University of the Ryukyus, Nishihara, Okinawa, 903-0213, Japan
| | - K Tsuji
- Entomological Laboratory, Faculty of Agriculture, University of the Ryukyus, Okinawa, 903-0213, Japan
| | - K Kobayashi
- Field Science Education and Research Center, Hokkaido Forest Research Station, Kyoto University, 553 Tawa, Shibecha-cho, Kawakami-gun, Hokkaido, 088-2339, Japan.
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24
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Arab A, Issa S, Aguilera-Olivares D. Editorial: Advances in the Evolutionary Ecology of Termites. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.698937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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25
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Comparative Antennal Morphometry and Sensilla Organization in the Reproductive and Non-Reproductive Castes of the Formosan Subterranean Termite. INSECTS 2021; 12:insects12070576. [PMID: 34202744 PMCID: PMC8307099 DOI: 10.3390/insects12070576] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/17/2021] [Accepted: 06/18/2021] [Indexed: 12/02/2022]
Abstract
Simple Summary Insects use antennae to perceive the chemical environment, and olfaction (the sense of smell) is essential for a variety of behavioral responses. Termites are social insects that display a division of labor based on an elaborate caste system consisting of reproductive (queen and king) and non-reproductive individuals (workers and soldiers). Whether these castes have different senses of smell is poorly understood. In this study, we characterized the morphology of antennae in alates (winged reproductives), workers, and soldiers in the Formosan subterranean termite, Coptotermes formosanus, and further analyzed the diversity and abundance of the antennal sensilla (sensory receptors) in each caste. We found that both female and male alates had longer antennae and greater numbers of sensilla than workers and soldiers, but all castes possessed the same nine types of antennal sensilla. Each type of sensilla had a specific spatial distribution along the antenna. The quantitative composition of sensilla differed between the reproductive and non-reproductive castes, but few differences were found between female and male alates or between worker and soldier castes. These results suggest that the olfactory morphology is associated with the reproductive division of labor in subterranean termites. Abstract Antennae are the primary sensory organs in insects, where a variety of sensilla are distributed for the perception of the chemical environment. In eusocial insects, colony function is maintained by a division of labor between reproductive and non-reproductive castes, and chemosensation is essential for regulating their specialized social activities. Several social species in Hymenoptera display caste-specific characteristics in antennal morphology and diversity of sensilla, reflecting their differential tasks. In termites, however, little is known about how the division of labor is associated with chemosensory morphology among castes. Using light and scanning electron microscopy, we performed antennal morphometry and characterized the organization of sensilla in reproductive (female and male alates) and non-reproductive (worker and soldier) castes in the Formosan subterranean termite, Coptotermes formosanus Shiraki. Here, we show that the antennal sensilla in alates are twice as abundant as in workers and soldiers, along with the greater number of antennal segments and antennal length in alates. However, all castes exhibit the same types of antennal sensilla, including basiconicum, campaniformium, capitulum, chaeticum I, chaeticum II, chaeticum III, marginal, trichodeum I, and trichodeum I. The quantitative composition of sensilla diverges between reproductive and non-reproductive castes, but not between female and male alates or between worker and soldier castes. The sensilla display spatial-specific distribution, with basiconicum exclusively and capitulum predominantly found on the ventral side of antennae. In addition, the abundance of chemosensilla increases toward the distal end of antennae in each caste. This research provides morphological signatures of chemosensation and their implications for the division of labor, and suggests future neurophysiological and molecular studies to address the mechanisms of chemical communication in termites.
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26
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Pie MR, Carrijo TF, Caron FS. The diversification of termites: Inferences from a complete species‐level phylogeny. ZOOL SCR 2021. [DOI: 10.1111/zsc.12502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Marcio R. Pie
- Departamento de Zoologia Universidade Federal do Paraná Curitiba Brazil
| | - Tiago F. Carrijo
- Centro de Ciências Naturais e Humanas Universidade Federal do ABC São Bernardo do Campo Brazil
| | - Fernanda S. Caron
- Departamento de Zoologia Universidade Federal do Paraná Curitiba Brazil
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27
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Tasaki E, Takata M, Matsuura K. Why and how do termite kings and queens live so long? Philos Trans R Soc Lond B Biol Sci 2021; 376:20190740. [PMID: 33678028 PMCID: PMC7938161 DOI: 10.1098/rstb.2019.0740] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/21/2020] [Indexed: 12/23/2022] Open
Abstract
Lifespan varies greatly across the tree of life. Of the various explanations for this phenomenon, those that involve trade-offs between reproduction and longevity have gained considerable support. There is an important exception: social insect reproductives (queens and in termites, also kings) exhibit both high reproductive outputs and extraordinarily long lives. As both the ultimate and proximate mechanisms underlying the absence of the fecundity/longevity trade-off could shed light on the unexpected dynamics and molecular mechanisms of extended longevity, reproductives of social insects have attracted much attention in the field of ageing research. Here, we highlight current ecological and physiological studies on ageing and discuss the various possible evolutionary and molecular explanations of the extended lifespans of termite reproductives. We integrate these findings into a coherent framework revealing the evolution of longevity in these reproductives. Studies on termites may explain why and how ageing is shaped by natural selection. 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)
- Eisuke Tasaki
- Laboratory of Insect Ecology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
| | - Mamoru Takata
- Laboratory of Insect Ecology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
| | - Kenji Matsuura
- Laboratory of Insect Ecology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
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Kramer BH, Nehring V, Buttstedt A, Heinze J, Korb J, Libbrecht R, Meusemann K, Paxton RJ, Séguret A, Schaub F, Bernadou A. Oxidative stress and senescence in social insects: a significant but inconsistent link? Philos Trans R Soc Lond B Biol Sci 2021; 376:20190732. [PMID: 33678022 PMCID: PMC7938172 DOI: 10.1098/rstb.2019.0732] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/14/2020] [Indexed: 12/29/2022] Open
Abstract
The life-prolonging effects of antioxidants have long entered popular culture, but the scientific community still debates whether free radicals and the resulting oxidative stress negatively affect longevity. Social insects are intriguing models for analysing the relationship between oxidative stress and senescence because life histories differ vastly between long-lived reproductives and the genetically similar but short-lived workers. Here, we present the results of an experiment on the accumulation of oxidative damage to proteins, and a comparative analysis of the expression of 20 selected genes commonly involved in managing oxidative damage, across four species of social insects: a termite, two bees and an ant. Although the source of analysed tissue varied across the four species, our results suggest that oxidative stress is a significant factor in senescence and that its manifestation and antioxidant defenses differ among species, making it difficult to find general patterns. More detailed and controlled investigations on why responses to oxidative stress may differ across social species may lead to a better understanding of the relations between oxidative stress, antioxidants, social life history and senescence. 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)
- Boris H. Kramer
- Faculty of Science and Engineering, Theoretical Research in Evolutionary Life Sciences, RUG, 9747 AG Groningen, The Netherlands
| | - Volker Nehring
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), University of Freiburg, Hauptstraße 1, 79104 Freiburg (Brsg.), Germany
| | - Anja Buttstedt
- Institute for Biology - Molecular Ecology, Martin-Luther-University Halle-Saale, Hoher Weg 4, 06099 Halle, Germany
| | - Jürgen Heinze
- Zoology, Department of Evolutionary Biology, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Judith Korb
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), University of Freiburg, Hauptstraße 1, 79104 Freiburg (Brsg.), Germany
| | - Romain Libbrecht
- Institute of Organismic and Molecular Evolution (IOME), Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 15, 55128 Mainz, Germany
| | - Karen Meusemann
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), University of Freiburg, Hauptstraße 1, 79104 Freiburg (Brsg.), Germany
| | - Robert J. Paxton
- Institute for Biology - General Zoology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle, Germany
| | - Alice Séguret
- Institute for Biology - General Zoology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle, Germany
| | - Florentine Schaub
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), University of Freiburg, Hauptstraße 1, 79104 Freiburg (Brsg.), Germany
| | - Abel Bernadou
- Zoology, Department of Evolutionary Biology, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
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29
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Korb J, Meusemann K, Aumer D, Bernadou A, Elsner D, Feldmeyer B, Foitzik S, Heinze J, Libbrecht R, Lin S, Majoe M, Monroy Kuhn JM, Nehring V, Negroni MA, Paxton RJ, Séguret AC, Stoldt M, Flatt T. Comparative transcriptomic analysis of the mechanisms underpinning ageing and fecundity in social insects. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190728. [PMID: 33678016 PMCID: PMC7938167 DOI: 10.1098/rstb.2019.0728] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2021] [Indexed: 12/13/2022] Open
Abstract
The exceptional longevity of social insect queens despite their lifelong high fecundity remains poorly understood in ageing biology. To gain insights into the mechanisms that might underlie ageing in social insects, we compared gene expression patterns between young and old castes (both queens and workers) across different lineages of social insects (two termite, two bee and two ant species). After global analyses, we paid particular attention to genes of the insulin/insulin-like growth factor 1 signalling (IIS)/target of rapamycin (TOR)/juvenile hormone (JH) network, which is well known to regulate lifespan and the trade-off between reproduction and somatic maintenance in solitary insects. Our results reveal a major role of the downstream components and target genes of this network (e.g. JH signalling, vitellogenins, major royal jelly proteins and immune genes) in affecting ageing and the caste-specific physiology of social insects, but an apparently lesser role of the upstream IIS/TOR signalling components. Together with a growing appreciation of the importance of such downstream targets, this leads us to propose the TI-J-LiFe (TOR/IIS-JH-Lifespan and Fecundity) network as a conceptual framework for understanding the mechanisms of ageing and fecundity in social insects and beyond. 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)
- Judith Korb
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), University of Freiburg, Hauptstraße 1, D-79104 Freiburg (Breisgau), Germany
| | - Karen Meusemann
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), University of Freiburg, Hauptstraße 1, D-79104 Freiburg (Breisgau), Germany
- Australian National Insect Collection, CSIRO National Research Collections Australia, Clunies Ross Street, Canberra, Acton 2601, Australia
| | - Denise Aumer
- Developmental Zoology, Molecular Ecology Research Group, Hoher Weg 4, D-06099 Halle (Saale), Germany
| | - Abel Bernadou
- Zoology/Evolutionary Biology, University of Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany
| | - Daniel Elsner
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), University of Freiburg, Hauptstraße 1, D-79104 Freiburg (Breisgau), Germany
| | - Barbara Feldmeyer
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Molecular Ecology, Senckenberg, Georg-Voigt-Straße 14-16, D-60325 Frankfurt, Germany
| | - Susanne Foitzik
- Institute of Organismic and Molecular Evolution (IOME), Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 15, D-55128 Mainz, Germany
| | - Jürgen Heinze
- Zoology/Evolutionary Biology, University of Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany
| | - Romain Libbrecht
- Institute of Organismic and Molecular Evolution (IOME), Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 15, D-55128 Mainz, Germany
| | - Silu Lin
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), University of Freiburg, Hauptstraße 1, D-79104 Freiburg (Breisgau), Germany
| | - Megha Majoe
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), University of Freiburg, Hauptstraße 1, D-79104 Freiburg (Breisgau), Germany
- Institute of Organismic and Molecular Evolution (IOME), Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 15, D-55128 Mainz, Germany
| | - José Manuel Monroy Kuhn
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), University of Freiburg, Hauptstraße 1, D-79104 Freiburg (Breisgau), Germany
| | - Volker Nehring
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), University of Freiburg, Hauptstraße 1, D-79104 Freiburg (Breisgau), Germany
| | - Matteo A. Negroni
- Institute of Organismic and Molecular Evolution (IOME), Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 15, D-55128 Mainz, Germany
| | - Robert J. Paxton
- Institute for Biology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle, Germany
| | - Alice C. Séguret
- Institute for Biology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle, Germany
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstraße 1, 48149 Münster, Germany
| | - Marah Stoldt
- Institute of Organismic and Molecular Evolution (IOME), Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 15, D-55128 Mainz, Germany
| | - Thomas Flatt
- Department of Biology, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland
| | - the So-Long consortium
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), University of Freiburg, Hauptstraße 1, D-79104 Freiburg (Breisgau), Germany
- Australian National Insect Collection, CSIRO National Research Collections Australia, Clunies Ross Street, Canberra, Acton 2601, Australia
- Developmental Zoology, Molecular Ecology Research Group, Hoher Weg 4, D-06099 Halle (Saale), Germany
- Zoology/Evolutionary Biology, University of Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Molecular Ecology, Senckenberg, Georg-Voigt-Straße 14-16, D-60325 Frankfurt, Germany
- Institute of Organismic and Molecular Evolution (IOME), Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 15, D-55128 Mainz, Germany
- Institute for Biology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle, Germany
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstraße 1, 48149 Münster, Germany
- Department of Biology, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland
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30
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Penick CA, Ghaninia M, Haight KL, Opachaloemphan C, Yan H, Reinberg D, Liebig J. Reversible plasticity in brain size, behaviour and physiology characterizes caste transitions in a socially flexible ant ( Harpegnathos saltator). Proc Biol Sci 2021; 288:20210141. [PMID: 33849311 DOI: 10.1098/rspb.2021.0141] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Phenotypic plasticity allows organisms to respond to changing environments throughout their lifetime, but these changes are rarely reversible. Exceptions occur in relatively long-lived vertebrate species that exhibit seasonal plasticity in brain size, although similar changes have not been identified in short-lived species, such as insects. Here, we investigate brain plasticity in reproductive workers of the ant Harpegnathos saltator. Unlike most ant species, workers of H. saltator are capable of sexual reproduction, and they compete in a dominance tournament to establish a group of reproductive workers, termed 'gamergates'. We demonstrated that, compared to foragers, gamergates exhibited a 19% reduction in brain volume in addition to significant differences in behaviour, ovarian status, venom production, cuticular hydrocarbon profile, and expression profiles of related genes. In experimentally manipulated gamergates, 6-8 weeks after being reverted back to non-reproductive status their phenotypes shifted to the forager phenotype across all traits we measured, including brain volume, a trait in which changes were previously shown to be irreversible in honeybees and Drosophila. Brain plasticity in H. saltator is therefore more similar to that found in some long-lived vertebrates that display reversible changes in brain volume throughout their lifetimes.
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Affiliation(s)
- Clint A Penick
- Department of Ecology, Evolution, and Organismal Biology, Kennesaw State University, Kennesaw, GA 30144, USA.,School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Majid Ghaninia
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Kevin L Haight
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Comzit Opachaloemphan
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Hua Yan
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA.,Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA.,Department of Biology, University of Florida, Gainesville, FL 32611, USA.,Center for Smell and Taste, University of Florida, Gainesville, FL 32611, USA
| | - Danny Reinberg
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA.,Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA
| | - Jürgen Liebig
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
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31
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West SA, Cooper GA, Ghoul MB, Griffin AS. Ten recent insights for our understanding of cooperation. Nat Ecol Evol 2021; 5:419-430. [PMID: 33510431 PMCID: PMC7612052 DOI: 10.1038/s41559-020-01384-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 12/11/2020] [Indexed: 01/29/2023]
Abstract
Since Hamilton published his seminal papers in 1964, our understanding of the importance of cooperation for life on Earth has evolved beyond recognition. Early research was focused on altruism in the social insects, where the problem of cooperation was easy to see. In more recent years, research into cooperation has expanded across the entire tree of life, and has been revolutionized by advances in genetic, microbiological and analytical techniques. We highlight ten insights that have arisen from these advances, which have illuminated generalizations across different taxa, making the world simpler to explain. Furthermore, progress in these areas has opened up numerous new problems to solve, suggesting exciting directions for future research.
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Affiliation(s)
- Stuart A West
- Department of Zoology, University of Oxford, Oxford, UK.
| | - Guy A Cooper
- Department of Zoology, University of Oxford, Oxford, UK
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32
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Holland JG, Nakayama S, Porfiri M, Nov O, Bloch G. Body Size and Behavioural Plasticity Interact to Influence the Performance of Free-Foraging Bumble Bee Colonies. INSECTS 2021; 12:236. [PMID: 33802199 PMCID: PMC8001989 DOI: 10.3390/insects12030236] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 03/05/2021] [Accepted: 03/08/2021] [Indexed: 11/20/2022]
Abstract
Specialisation and plasticity are important for many forms of collective behaviour, but the interplay between these factors is little understood. In insect societies, workers are often developmentally primed to specialise in different tasks, sometimes with morphological or physiological adaptations, facilitating a division of labour. Workers may also plastically switch between tasks or vary their effort. The degree to which developmentally primed specialisation limits plasticity is not clear and has not been systematically tested in ecologically relevant contexts. We addressed this question in 20 free-foraging bumble bee (Bombus terrestris) colonies by continually manipulating colonies to contain either a typically diverse, or a reduced ("homogeneous"), worker body size distribution while keeping the same mean body size, over two trials. Pooling both trials, diverse colonies produced a larger comb mass, an index of colony performance. The link between body size and task was further corroborated by the finding that foragers were larger than nurses even in homogeneous colonies with a very narrow body size range. However, the overall effect of size diversity stemmed mostly from one trial. In the other trial, homogeneous and diverse colonies showed comparable performance. By comparing behavioural profiles based on several thousand observations of individuals, we found evidence that workers in homogeneous colonies in this trial rescued colony performance by plastically increasing behavioural specialisation and/or individual effort, compared to same-sized individuals in diverse colonies. Our results are consistent with a benefit to colonies of large and small specialists under certain conditions, but also suggest that plasticity or effort can compensate for reduced (size-related) specialisation. Thus, we suggest that an intricate interplay between specialisation and plasticity is functionally adaptive in bumble bee colonies.
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Affiliation(s)
- Jacob G. Holland
- Department of Ecology, Evolution & Behaviour, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Shinnosuke Nakayama
- Department of Mechanical and Aerospace Engineering, New York University Tandon School of Engineering, Brooklyn, NY 11201, USA; (S.N.); (M.P.)
| | - Maurizio Porfiri
- Department of Mechanical and Aerospace Engineering, New York University Tandon School of Engineering, Brooklyn, NY 11201, USA; (S.N.); (M.P.)
- Center for Urban Science and Progress, New York University Tandon School of Engineering, Brooklyn, NY 11201, USA
- Department of Biomedical Engineering, New York University Tandon School of Engineering, Brooklyn, NY 11201, USA
| | - Oded Nov
- Department of Technology Management and Innovation, New York University Tandon School of Engineering, Brooklyn, NY 11201, USA;
| | - Guy Bloch
- Department of Ecology, Evolution & Behaviour, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel
- The Federmann Center for the Study of Rationality, The Hebrew University of Jerusalem, Rehovot 7610001, Israel
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33
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Korb J, Greiner C, Foget M, Geiler A. How Can Termites Achieve Their Unparalleled Postembryonic Developmental Plasticity? A Test for the Role of Intermolt-Specific High Juvenile Hormone Titers. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.619594] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Termites are “social cockroaches” and amongst the most phenotypically plastic insects. The different castes (i.e., two types of reproductives, workers, and soldiers) within termite societies are all encoded by a single genome and present the result of differential postembryonic development. Besides the default progressive development into winged sexuals of solitary hemimetabolous insects, termites have two postembryonic, non-terminal molts (stationary and regressive; i.e., molts associated, respectively, with no change or reduction of size/morphological differentiation) which allow them to retain workers, and two terminal developmental types to become soldiers and replacement reproductives. Despite this unique plasticity, especially the mechanisms underlying the non-terminal development are poorly understood. In 1982, Nijhout and Wheeler proposed a model how this diversity might have evolved. They proposed that varying juvenile hormone (JH) titers at the start, mid-phase, and end of each intermolt period account for the developmental diversity. We tested this rarely addressed model in the lower termite Cryptotermes secundus using phase-specific pharmacological manipulations of JH titers. Our results partially support the Nijhout and Wheeler model. These data are supplemented with gene expression studies of JH-related genes that characterize different postembryonic developmental trajectories. Our study provides new insights into the evolution of the unique postembryonic developmental plasticity of termites that constitutes the foundation of their social life.
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Oguchi K, Maekawa K, Miura T. Regulatory Mechanisms Underlying the Differentiation of Neotenic Reproductives in Termites: Partial Release From Arrested Development. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.635552] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Eusocial insects exhibit reproductive division of labor, in which only a part of colony members differentiates into reproductives. In termite colonies, the division of labors is performed among multiple types of individuals (i.e., castes), such as reproductives, workers, and soldiers to organize their society. Caste differentiation occurs according to extrinsic factors, such as social interactions, leading to developmental modifications during postembryonic development, and consequently, the caste ratio in a colony is appropriately coordinated. In particular, when the current reproductives die or become senescent, some immature individuals molt into supplementary reproductives, also known as “neotenics,” that take over the reproductive task in their natal colony. Neotenics exhibit variety of larval features, such as winglessness, and thus, immature individuals are suggested to differentiate by a partial release from arrested development, particularly in the reproductive organs. These neotenic features, which have long been assumed to develop via heterochronic regulation, provide us opportunities to understand the developmental mechanisms and evolutionary origin of the novel caste. This article overviews the accumulated data on the physiological and developmental mechanisms that regulate the neotenic differentiation in termites. Furthermore, the evolutionary trajectories leading to neotenic differentiation are discussed, namely the acquisition of a regulatory mechanism that enable the partial release from a developmentally arrested state.
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35
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Revely L, Sumner S, Eggleton P. The Plasticity and Developmental Potential of Termites. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.552624] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Phenotypic plasticity provides organisms with the potential to adapt to their environment and can drive evolutionary innovations. Developmental plasticity is environmentally induced variation in phenotypes during development that arise from a shared genomic background. Social insects are useful models for studying the mechanisms of developmental plasticity, due to the phenotypic diversity they display in the form of castes. However, the literature has been biased toward the study of developmental plasticity in the holometabolous social insects (i.e., bees, wasps, and ants); the hemimetabolous social insects (i.e., the termites) have received less attention. Here, we review the phenotypic complexity and diversity of termites as models for studying developmental plasticity. We argue that the current terminology used to define plastic phenotypes in social insects does not capture the diversity and complexity of these hemimetabolous social insects. We suggest that terminology used to describe levels of cellular potency could be helpful in describing the many levels of phenotypic plasticity in termites. Accordingly, we propose a conceptual framework for categorizing the changes in potential of individuals to express alternative phenotypes through the developmental life stages of termites. We compile from the literature an exemplar dataset on the phenotypic potencies expressed within and between species across the phylogeny of the termites and use this to illustrate how the potencies of different life stages of different species can be described using this framework. We highlight how this conceptual framework can help exploit the rich phenotypic diversity of termites to address fundamental questions about the evolution and mechanisms of developmental plasticity. This conceptual contribution is likely to have wider relevance to the study of other hemimetabolous insects, such as aphids and gall-forming thrips, and may even prove useful for some holometabolous social insects which have high caste polyphenism.
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36
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Ye C, Song Z, Wu T, Zhang W, Saba NU, Xing L, Su X. Endocuticle is involved in caste differentiation of the lower termite. Curr Zool 2021; 67:489-499. [PMID: 34616947 PMCID: PMC8489109 DOI: 10.1093/cz/zoab005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 01/19/2021] [Indexed: 12/30/2022] Open
Abstract
Caste differentiation in termites is one of the most conspicuous examples of facultative polyphenism in animals. It is clear that specific cuticular formation occurs in hard exocuticles during caste differentiation. However, the developmental pattern of the soft endocuticle in the differentiation pathways of castes is unknown. To reveal whether the endocuticle is involved in caste differentiation, we compared the exocuticle and endocuticle thickness of individuals in 2 pathways (nymph line and worker line) of caste differentiation in the termite Reticulitermes aculabialis. The endocuticle protein genes were identified by transcriptome analysis and the expression patterns of these genes were confirmed in caste differentiation. We found that the endocuticle structure showed dynamic changes in 2 pathways, and the first difference in endocuticle structure occurred after larvae differentiation bifurcated into workers and nymphs. The thinning of the endocuticle was a significant event from nymphs developing into alates with the thickest exocuticle and thinnest endocuticle. The thickest endocuticle layers were found in the heads of the workers and the ultrastructure of the endocuticle in the heads was more complex than that in the thorax–abdomens. Six endocuticle protein genes were identified and annotated as endocuticle structural glycoproteins SgAbd-2, SgAbd-9, and Abd-5. The expression levels of endocuticle protein genes changed dramatically during caste development and the expression levels in neotenic reproductives (secondary reproductives) were significantly higher than those in alates (primary reproductives). These results reveal the roles of endocuticles in caste differentiation and adaptation to the environment.
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Affiliation(s)
- Chenxu Ye
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an 710069, China.,College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Zhuanzhuan Song
- College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Taoyu Wu
- College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Wenxiu Zhang
- College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Noor Us Saba
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an 710069, China.,College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Lianxi Xing
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an 710069, China.,College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Xiaohong Su
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an 710069, China.,College of Life Sciences, Northwest University, Xi'an 710069, China
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37
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Lee SB, Chouvenc T, Patel J, Su NY. Altered Mobility and Accumulation of Inefficient Workers in Juvenile Hybrid Termite Colonies. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.589762] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Hybridization of two different species is an important mechanism to have gene flows between species. Recently, mating of two economically important invasive species of subterranean termites (Coptotermes formosanusandCoptotermes gestroi) have been observed in the field and hybrids colonies have been established in the laboratory. It was previously reported that incipient colonies (~1 year old) of hybridCoptotermesspecies contained more termites than colonies of parental species, showing hybrid vigor. In this study, colony vigor and individual termite vigor were investigated in juvenile colonies (~2 year old), using colony growth parameters and the movement activity of individual termites as proxies for the evaluation of hybrid vigor beyond the initial colony foundation. After 2 years from colony foundations, hybrid colonies showed no more hybrid vigor. In addition, movement activity of termites in hybrid colonies was significantly slower than in termites from conspecific colonies. It is suggested that a reduction in the molting rates of individuals in hybrid colonies may have a negative impact on their physiology and their movement activity. These possible changes in physiology may affect the movement of individuals, and accumulation of these inefficient termites in hybrid colonies may contribute to the loss of hybrid vigor at 2 years of age in hybrid colonies.
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Sun Q, Hampton JD, Merchant A, Haynes KF, Zhou X. Cooperative policing behaviour regulates reproductive division of labour in a termite. Proc Biol Sci 2020; 287:20200780. [PMID: 32517622 DOI: 10.1098/rspb.2020.0780] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Reproductive conflicts are common in insect societies where helping castes retain reproductive potential. One of the mechanisms regulating these conflicts is policing, a coercive behaviour that reduces direct reproduction by other individuals. In eusocial Hymenoptera (ants, bees and wasps), workers or the queen act aggressively towards fertile workers, or destroy their eggs. In many termite species (order Blattodea), upon the death of the primary queen and king, workers and nymphs can differentiate into neotenic reproductives and inherit the breeding position. During this process, competition among neotenics is inevitable, but how this conflict is resolved remains unclear. Here, we report a policing behaviour that regulates reproductive division of labour in the eastern subterranean termite, Reticulitermes flavipes. Our results demonstrate that the policing behaviour is a cooperative effort performed sequentially by successful neotenics and workers. A neotenic reproductive initiates the attack of the fellow neotenic by biting and displays alarm behaviour. Workers are then recruited to cannibalize the injured neotenic. Furthermore, the initiation of policing is age-dependent, with older reproductives attacking younger ones, thereby inheriting the reproductive position. This study provides empirical evidence of policing behaviour in termites, which represents a convergent trait shared between eusocial Hymenoptera and Blattodea.
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Affiliation(s)
- Qian Sun
- Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.,Department of Entomology, University of Kentucky, S-225 Agricultural Science Center North, Lexington, KY 40546-0091, USA
| | - Jordan D Hampton
- Department of Entomology, University of Kentucky, S-225 Agricultural Science Center North, Lexington, KY 40546-0091, USA
| | - Austin Merchant
- Department of Entomology, University of Kentucky, S-225 Agricultural Science Center North, Lexington, KY 40546-0091, USA
| | - Kenneth F Haynes
- Department of Entomology, University of Kentucky, S-225 Agricultural Science Center North, Lexington, KY 40546-0091, USA
| | - Xuguo Zhou
- Department of Entomology, University of Kentucky, S-225 Agricultural Science Center North, Lexington, KY 40546-0091, USA
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Male neotenic reproductives accelerate additional differentiation of female reproductives by lowering JH titer in termites. Sci Rep 2020; 10:9435. [PMID: 32523105 PMCID: PMC7286905 DOI: 10.1038/s41598-020-66403-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 05/19/2020] [Indexed: 12/02/2022] Open
Abstract
Eusocial insects exhibit reproductive division of labor, in which only a fraction of colony members differentiate into reproductives. In termites, reproductives of both sexes are present in a colony and constantly engaged in reproduction. It has been suggested that the sex ratio of reproductives is maintained by social interactions. The presence of reproductives is known to inhibit the additional differentiation of same-sex reproductives, while it promotes the differentiation of opposite-sex reproductives. In this study, using the damp-wood termite Hodotermopsis sjostedti, physiological effects of male/female reproductives on the differentiation of supplementary reproductives (neotenics) were examined. The results showed that the only male-neotenic condition, i.e., the presence of male neotenics in the absence of female neotenics, accelerated the neotenic differentiation from female workers (i.e., pseudergates). Under this condition, the rise of juvenile hormone (JH) titer was repressed in females, and the application of a JH analog inhibited the female neotenic differentiation, indicating that the low JH titer leads to rapid differentiation. Thus, the only male-neotenic condition that actively promotes reproductive differentiation by manipulating physiological condition of females is suggested to be a mechanism underlying sexual asymmetry in reproductive function, which may lead the female-biased sex allocation of reproductives.
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Miura T, Maekawa K. The making of the defensive caste: Physiology, development, and evolution of the soldier differentiation in termites. Evol Dev 2020; 22:425-437. [PMID: 32291940 DOI: 10.1111/ede.12335] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 02/11/2020] [Accepted: 03/08/2020] [Indexed: 12/29/2022]
Abstract
Termites (Blattodea, Termitoidea, or Isoptera) constitute one of the major lineages of eusocial insects. In termite societies, multiple types of functional individuals, that is, castes, perform divisions of labors to coordinate social behaviors. Among other castes, the soldier caste is distinctive since it is sterile and exclusively specialized into defensive behavior with largely modified morphological features. Therefore, many of the previous studies have been focused on soldiers, in terms of ecology, behavior, and evolution as well as developmental and physiological mechanisms. This article overviews the accumulation of studies especially focusing on the developmental and physiological mechanisms underlying the soldier differentiation in termites. Furthermore, the evolutionary trajectories that have led the acquisition of soldier caste and have diversified the soldier characteristics in association with the social evolution are discussed.
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Affiliation(s)
- Toru Miura
- Department of Biological Sciences, Misaki Marine Biological Station, School of Science, The University of Tokyo, Japan
| | - Kiyoto Maekawa
- Department of Biology, Faculty of Science, Academic Assembly, University of Toyama, Toyama, Japan
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41
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Wu J, Xu H, Hassan A, Huang Q. Interspecific Hybridization between the Two Sympatric Termite Reticulitermes Species under Laboratory Conditions. INSECTS 2019; 11:insects11010014. [PMID: 31877914 PMCID: PMC7022586 DOI: 10.3390/insects11010014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/10/2019] [Accepted: 12/13/2019] [Indexed: 12/30/2022]
Abstract
Closely related species have similar reproductive behaviors and recognition systems, which contribute to interspecific interactions. However, few studies have explored interspecific reproduction choice and mating in termites. We investigated whether hybridization between two sympatric termites, Reticulitermes flaviceps and R. chinensis, occurs under laboratory conditions. We found that frequencies of acceptance were significantly higher than those of agonism between interspecific partners. There were no significant differences in frequencies of tandem and mating behaviors between intraspecific and interspecific partners. However, the allogrooming frequencies of interspecific partners were significantly higher than intraspecific partners. There were no significant differences in the duration of tandem, allogrooming, or mating behavior at each time between conspecific partners and heterospecfic partners. Genotyping analyses further showed that both intraspecific and interspecific mating were able to produce offspring. We conclude that interspecific hybridization does occur between two termite Reticulitermes species under laboratory conditions.
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42
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Affiliation(s)
- Kenji Matsuura
- Laboratory of Insect Ecology, Graduate School of AgricultureKyoto University Kyoto Japan
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43
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Cesar CS, Giacometti D, Costa-Leonardo AM, Casarin FE. Drywood Pest Termite Cryptotermes brevis (Blattaria: Isoptera: Kalotermitidae): a Detailed Morphological Study of Pseudergates. NEOTROPICAL ENTOMOLOGY 2019; 48:822-833. [PMID: 31197677 DOI: 10.1007/s13744-019-00687-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 04/11/2019] [Indexed: 06/09/2023]
Abstract
The Kalotermitidae Cryptotermes brevis (Walker) presents colonies that lack a true worker caste. They have totipotent worker-like individuals named pseudergates. Few studies have characterized the morphology of immature instars, including pseudergates. In order to identify these instars and characterize the pseudergates, we conducted a comparison between morphometric and morphological variations among immature individuals of C. brevis colonies. Juvenile hormone analog (JHA) was used in the first instar nymphs to induce regressive molts and compare morphological differences between nymphs and pseudergates. Results showed the existence of three larval instars and four nymphal instars. These immatures were morphologically characterized. Individuals classified as third instar larvae presented white body, 10 to 12 antennal articles, absent or small non-pigmented compound eyes, and absence of wing buds. Pseudergates presented pigmented abdomen and sclerotized cuticle, 10 to 12 antennal articles, and absent or small compound eyes, and few specimens had large pigmented compound eyes and absence of wing buds. First instar nymphs had pigmented abdomen and sclerotized cuticle, 10 to 12 antennal articles, both large non-pigmented and pigmented compound eyes, the presence of wing buds. Bioassays using JHA on first instar nymphs resulted in a large percentage of nymph-soldier intercastes. We concluded that abdomen pigmentation and sclerotized cuticle are good characters to differentiate pseudergates from larvae and the absence of wing buds is a good character to differentiate pseudergates from nymphs. Our findings not only contribute to the basic biological and morphological information of this species but also help to identify correctly pseudergates in further studies that involve applied bioassays.
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Affiliation(s)
- C S Cesar
- Dept of Ecology and Evolutionary Biology, Lab de Termitologia, Federal Univ of São Paulo (UNIFESP), Diadema, SP, Brasil.
- Dept of Ecology, Univ of São Paulo, São Paulo, SP, Brasil.
| | - D Giacometti
- Dept of Ecology and Evolutionary Biology, Lab de Termitologia, Federal Univ of São Paulo (UNIFESP), Diadema, SP, Brasil
| | - A M Costa-Leonardo
- Dept of Biological Sciences, Instituto de Biociências, São Paulo State Univ (UNESP), Rio Claro, SP, Brasil
| | - F E Casarin
- Dept of Ecology and Evolutionary Biology, Lab de Termitologia, Federal Univ of São Paulo (UNIFESP), Diadema, SP, Brasil
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Oguchi K, Miura T. Unique Morphogenesis in the Damp-Wood Termite: Abscission of the Stylus during Female Reproductive Caste Differentiation. Zoolog Sci 2019; 36:380-386. [DOI: 10.2108/zs190056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 05/06/2019] [Indexed: 11/17/2022]
Affiliation(s)
- Kohei Oguchi
- Misaki Marine Biological Station, The University of Tokyo, Miura, Kanagawa 238-0225, Japan
| | - Toru Miura
- Misaki Marine Biological Station, The University of Tokyo, Miura, Kanagawa 238-0225, Japan
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Nozaki T, Matsuura K. Evolutionary relationship of fat body endoreduplication and queen fecundity in termites. Ecol Evol 2019; 9:11684-11694. [PMID: 31695878 PMCID: PMC6822035 DOI: 10.1002/ece3.5664] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 08/24/2019] [Accepted: 08/26/2019] [Indexed: 01/01/2023] Open
Abstract
Endoreduplication or nuclear genome replication without cell division is widely observed in the metabolically active tissues of plants and animals. The fat body cells of adult female insects produce abundant yolk proteins and become polyploid, which is assumed to accelerate egg production. Recently, it was reported that in termites, endopolyploidy in the fat body occurs only in queens but not in the other females; however, the relationship between the fecundity and ploidy level in the fat body remains unclear. Termite queens exhibit a huge variation in their egg-producing capacity among different species; queens in the species with a foraging lifestyle, in which workers leave the nest to forage outside, are much more fecund than those in the species living in a single piece of wood. In this study, we conducted ploidy analyses on three foragings and three wood-dwelling termites via flow cytometry. In all the species, the fat body of queens contained significantly more polyploid cells than that of other nonreproductive females, considering their body size effect. However, the male fat body, which is not involved in yolk production, did not show consistency in polyploid cell numbers among the species studied. Moreover, highly fecund queens in foraging termites exhibit higher levels of endopolyploidy in their fat body than those with less fecundity in wood-dwelling termites. These results suggest that endopolyploidy in the fat body of termite queens can boost their egg production, and the level of endopolyploidy in their fat body is linked to their fecundity. Our study provides a novel insight into the evolutionary relationship between endoreduplication and caste specialization in social insects.
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Affiliation(s)
- Tomonari Nozaki
- Laboratory of Insect EcologyGraduate School of AgricultureKyoto UniversityKyotoJapan
- Center for the Development of New Model OrganismsNational Institute for Basic BiologyOkazakiJapan
| | - Kenji Matsuura
- Laboratory of Insect EcologyGraduate School of AgricultureKyoto UniversityKyotoJapan
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46
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Ye C, Rasheed H, Ran Y, Yang X, Xing L, Su X. Transcriptome changes reveal the genetic mechanisms of the reproductive plasticity of workers in lower termites. BMC Genomics 2019; 20:702. [PMID: 31500567 PMCID: PMC6734246 DOI: 10.1186/s12864-019-6037-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 08/16/2019] [Indexed: 11/10/2022] Open
Abstract
Background The reproductive plasticity of termite workers provides colonies with tremendous flexibility to respond to environmental changes, which is the basis for evolutionary and ecological success. Although it is known that all colony members share the same genetic background and that differences in castes are caused by differences in gene expression, the pattern of the specific expression of genes involved in the differentiation of workers into reproductives remains unclear. In this study, the isolated workers of Reticulitermes labralis developed into reproductives, and then comparative transcriptomes were used for the first time to reveal the molecular mechanisms underlying the reproductive plasticity of workers. Results We identified 38,070 differentially expressed genes and found a pattern of gene expression involved in the differentiation of the workers into reproductives. 12, 543 genes were specifically upregulated in the isolated workers. Twenty-five signal transduction pathways classified into environmental information processing were related to the differentiation of workers into reproductives. Ras functions as a signalling switch regulates the reproductive plasticity of workers. The catalase gene which is related to longevity was up-regulated in reproductives. Conclusion We demonstrate that workers leaving the natal colony can induce the expression of stage-specific genes in the workers, which leads to the differentiation of workers into reproductives and suggests that the signal transduction along the Ras-MAPK pathway crucially controls the reproductive plasticity of the workers. This study also provides an important model for revealing the molecular mechanism of longevity changes. Electronic supplementary material The online version of this article (10.1186/s12864-019-6037-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Chenxu Ye
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an, China.,College of Life Sciences, Northwest University, Xi'an, China
| | - Humaira Rasheed
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an, China
| | - Yuehua Ran
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an, China
| | - Xiaojuan Yang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an, China
| | - Lianxi Xing
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an, China.,College of Life Sciences, Northwest University, Xi'an, China
| | - Xiaohong Su
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an, China. .,College of Life Sciences, Northwest University, Xi'an, China.
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47
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Abstract
Workers in an ant colony can kill fungus-infected brood, thereby protecting the rest of the colony from fungal infection. This form of social immunity is analogous to the immune system of multicellular organisms where immune cells kill infected cells.
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Affiliation(s)
- Duur K Aanen
- Department of Plant Sciences, Laboratory of Genetics, Wageningen University, 6708 PB Wageningen, Netherlands.
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48
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Nii R, Oguchi K, Shinji J, Koshikawa S, Miura T. Reduction of a nymphal instar in a dampwood termite: heterochronic shift in the caste differentiation pathways. EvoDevo 2019; 10:10. [PMID: 31123582 PMCID: PMC6521406 DOI: 10.1186/s13227-019-0123-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 04/16/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Generally in termites, alates differentiate through multiple nymphal instars which gradually develop wing buds. However, in a dampwood termite, Hodotermopsis sjostedti, alates molt directly from a single nymphal instar with short wing buds. In this study, to examine the mechanism underlying the wing formation during the alate differentiation in H. sjostedti, histological and morphological observations were carried out on the developmental process of wing formation during the nymphal instar, in comparison with those in Zootermopsis nevadensis, which has two nymphal instars. Furthermore, the expression patterns of genes that are thought to be responsible for wing formation, i.e., wing-patterning genes and genes encoding hormone-related factors, were quantified during alate differentiation and compared between the two species. RESULTS The results showed that, in H. sjostedti, wings were formed in a complicatedly folded shape, not only inside the wing buds as seen in Z. nevadensis, but also under the dorsal thoracic cuticle, where the wing tips shifted toward the median thoracic part. Accordingly, the wing expansion pattern also differed from that in Z. nevadensis. Furthermore, the results of real-time qRT-PCR on overall expression profiles of wing-patterning genes and hormone-related genes suggest that the single nymphal instar in H. sjostedti well resembles to the second nymphal instar in Z. nevadensis. In particular, significant upregulation of vestigial (vg) and downregulation of Krüppel homolog 1 (Kr-h1) that were observed at the second nymphal instar in Z. nevadensis apparently occurred during the single nymphal instar in H. sjostedti. CONCLUSION The developmental events for wing formation are compacted into a single nymphal instar in H. sjostedti, and as a result, the unique wing formation is seen to compensate for the spatial restriction inside small wing buds, leading to the completion of functional wings.
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Affiliation(s)
- Ryotaro Nii
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido 060-0810 Japan
| | - Kohei Oguchi
- Misaki Marine Biological Station, School of Science, The University of Tokyo, Miura, Kanagawa 238-0225 Japan
| | - Junpei Shinji
- Misaki Marine Biological Station, School of Science, The University of Tokyo, Miura, Kanagawa 238-0225 Japan
| | - Shigeyuki Koshikawa
- Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Hokkaido 060-0810 Japan
| | - Toru Miura
- Misaki Marine Biological Station, School of Science, The University of Tokyo, Miura, Kanagawa 238-0225 Japan
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49
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Ye C, Li J, Ran Y, Rasheed H, Xing L, Su X. The nest fungus of the lower termite Reticulitermes labralis. Sci Rep 2019; 9:3384. [PMID: 30833643 PMCID: PMC6399267 DOI: 10.1038/s41598-019-40229-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 02/11/2019] [Indexed: 11/09/2022] Open
Abstract
Fitness-determining interactions with fungi have often been considered a by-product of social evolution in insects. In higher termites, the mutualistic association between the basidiomycete genus Termitomyces and Macrotermitinae is well known. However, whether and how lower termites use fungi is unclear. Here, we found a large amount of brown sclerotium-forming fungi in egg piles of the lower termite Reticulitermes labralis and identified the sclerotia as Fibulorhizoctonia sp. There was a significant difference in morphology between the sclerotia and the termite eggs. The workers of R. labralis and R. chinensis actively gathered the sclerotia into the egg piles within their nests, whereas the workers of R. aculabialis did not gather sclerotia outside their nests. None of the sclerotia in the egg piles germinated in the presence of workers. However, the sclerotia germinated in the absence of workers, and then the hyphae killed the termite eggs. The data from cellulase activity demonstrated that Fibulorhizoctonia sp. was able to exhaustively digest cellulose into glucose.We confirmed for the first time that the workers carrying the sclerotia into the piles of eggs is not due to mistaking the sclerotia for their eggs and that the workers of R. labralis may be able to select favourite fungi.
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Affiliation(s)
- Chenxu Ye
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, Xi'an, China.,Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an, China.,College of Life Sciences, Northwest University, Xi'an, China
| | - Jing Li
- College of Life Sciences, Northwest University, Xi'an, China
| | - Yuehua Ran
- College of Life Sciences, Northwest University, Xi'an, China
| | - Humaira Rasheed
- College of Life Sciences, Northwest University, Xi'an, China
| | - Lianxi Xing
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, Xi'an, China.,Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an, China.,College of Life Sciences, Northwest University, Xi'an, China
| | - Xiaohong Su
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, Xi'an, China. .,Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an, China. .,College of Life Sciences, Northwest University, Xi'an, China.
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50
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Monroy Kuhn JM, Meusemann K, Korb J. Long live the queen, the king and the commoner? Transcript expression differences between old and young in the termite Cryptotermes secundus. PLoS One 2019; 14:e0210371. [PMID: 30759161 PMCID: PMC6373952 DOI: 10.1371/journal.pone.0210371] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 12/20/2018] [Indexed: 01/09/2023] Open
Abstract
Social insects provide promising new avenues for aging research. Within a colony, individuals that share the same genetic background can differ in lifespan by up to two orders of magnitude. Reproducing queens (and in termites also kings) can live for more than 20 years, extraordinary lifespans for insects. We studied aging in a termite species, Cryptotermes secundus, which lives in less socially complex societies with a few hundred colony members. Reproductives develop from workers which are totipotent immatures. Comparing transcriptomes of young and old individuals, we found evidence for aging in reproductives that was especially associated with DNA and protein damage and the activity of transposable elements. By contrast, workers seemed to be better protected against aging. Thus our results differed from those obtained for social insects that live in more complex societies. Yet, they are in agreement with lifespan estimates for the study species. Our data are also in line with expectations from evolutionary theory. For individuals that are able to reproduce, it predicts that aging should only start after reaching maturity. As C. secundus workers are immatures with full reproductive options we expect them to invest into anti-aging processes. Our study illustrates that the degree of aging can differ between social insects and that it may be associated with caste-specific opportunities for reproduction.
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Affiliation(s)
- José Manuel Monroy Kuhn
- Evolutionary Biology and Ecology, Albert-Ludwigs-Universität Freiburg, Freiburg, Baden-Württemberg, Germany
- * E-mail: (JMMK); (JK)
| | - Karen Meusemann
- Evolutionary Biology and Ecology, Albert-Ludwigs-Universität Freiburg, Freiburg, Baden-Württemberg, Germany
| | - Judith Korb
- Evolutionary Biology and Ecology, Albert-Ludwigs-Universität Freiburg, Freiburg, Baden-Württemberg, Germany
- * E-mail: (JMMK); (JK)
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