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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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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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Brossette L, Meunier J, Dupont S, Bagnères A, Lucas C. Unbalanced biparental care during colony foundation in two subterranean termites. Ecol Evol 2019; 9:192-200. [PMID: 30680106 PMCID: PMC6342128 DOI: 10.1002/ece3.4710] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 10/05/2018] [Accepted: 10/11/2018] [Indexed: 11/11/2022] Open
Abstract
Parental care is a major component of reproduction in social organisms, particularly during the foundation steps. Because investment into parental care is often costly, each parent is predicted to maximize its fitness by providing less care than its partner. However, this sexual conflict is expected to be low in species with lifelong monogamy, because the fitness of each parent is typically tied to the other's input. Somewhat surprisingly, the outcomes of this tug-of-war between maternal and paternal investments have received important attention in vertebrate species, but remain less known in invertebrates. In this study, we investigated how queens and kings share their investment into parental care and other social interactions during colony foundation in two termites with lifelong monogamy: the invasive species Reticulitermes flavipes and the native species R. grassei. Behaviors of royal pairs were recorded during six months using a non-invasive approach. Our results showed that queens and kings exhibit unbalanced investment in terms of grooming, antennation, trophallaxis, and vibration behavior. Moreover, both parents show behavioral differences toward their partner or their descendants. Our results also revealed differences among species, with R. flavipes exhibiting shorter periods of grooming and antennation toward eggs or partners. They also did more stomodeal trophallaxis and less vibration behavior. Overall, this study emphasizes that despite lifelong monogamy, the two parents are not equally involved in the measured forms of parental care and suggests that kings might be specialized in other tasks. It also indicates that males could play a central, yet poorly studied role in the evolution and maintenance of the eusocial organization.
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Affiliation(s)
- Lou Brossette
- Institut de Recherche sur la Biologie de l'Insecte (UMR7261)CNRS – University of ToursToursFrance
| | - Joël Meunier
- Institut de Recherche sur la Biologie de l'Insecte (UMR7261)CNRS – University of ToursToursFrance
| | - Simon Dupont
- Institut de Recherche sur la Biologie de l'Insecte (UMR7261)CNRS – University of ToursToursFrance
| | - Anne‐Geneviève Bagnères
- Institut de Recherche sur la Biologie de l'Insecte (UMR7261)CNRS – University of ToursToursFrance
- CEFE, CNRS UMR5175, Univ. Montpellier, Univ. Paul Valéry Montpellier 3, EPHE, IRDMontpellierFrance
| | - Christophe Lucas
- Institut de Recherche sur la Biologie de l'Insecte (UMR7261)CNRS – University of ToursToursFrance
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Baudouin G, Bech N, Bagnères AG, Dedeine F. Spatial and genetic distribution of a north American termite, Reticulitermes flavipes, across the landscape of Paris. Urban Ecosyst 2018. [DOI: 10.1007/s11252-018-0747-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Su X, Yang X, Li J, Xing L, Liu H, Chen J. The transition path from female workers to neotenic reproductives in the termite Reticulitermes labralis. Evol Dev 2017; 19:218-226. [PMID: 28869353 DOI: 10.1111/ede.12229] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Termite workers are characterized by unique flexibility in that a worker can develop in one of three ways: remain a worker, become a soldier within two successive moults, or become a neotenic reproductive (NR) within a single moult. However, is it true that workers can transform into NRs within a single moult? Actually, the developmental pathways of workers turning into NRs remains unclear. In this study, we show for the first time that the female workers of Reticulitermes labralis develop into NRs after a pre-NRs stage. We found that a female worker became a NR after two successive moults, whereas the male workers copulated directly with queens without undergoing any moults. After the first moult led the female workers into the pre-NR stage, the length of their abdomens, seventh sternites and ovaries significantly increased. After the second moult from the pre-NRs stage into NRs, the follicle cells returned to normal, and a few oocytes and follicle cells underwent apoptosis. These results demonstrated that the female pre-NR type was a transitional type during the development of female workers to the NR caste, and the starting point for oogenesis resumption was the NR stage. We confirmed there were fundamental differences in the reproductive pathway of the male and female workers. Therefore, we determined that the transformation process of the female NRs from workers may be a very complex process, and the reproductive biology of the workers has great potential to provide important and spectacular insights into the evolution strategy of termites.
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Affiliation(s)
- Xiaohong Su
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an, China.,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
| | - Xiaojuan Yang
- College of Life Sciences, Northwest University, Xi'an, China
| | - Jing Li
- College of Life Sciences, Northwest University, Xi'an, China
| | - Lianxi Xing
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an, China.,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
| | - He Liu
- College of Life Sciences, Northwest University, Xi'an, China
| | - Jiaoling Chen
- College of Life Sciences, Northwest University, Xi'an, China
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Induction of a reproductive-specific cuticular hydrocarbon profile by a juvenile hormone analog in the termite Zootermopsis nevadensis. CHEMOECOLOGY 2016. [DOI: 10.1007/s00049-016-0219-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Lefebvre T, Vargo EL, Zimmermann M, Dupont S, Kutnik M, Bagnères AG. Subterranean termite phylogeography reveals multiple postglacial colonization events in southwestern Europe. Ecol Evol 2016; 6:5987-6004. [PMID: 27547371 PMCID: PMC4983608 DOI: 10.1002/ece3.2333] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 06/30/2016] [Indexed: 12/23/2022] Open
Abstract
A long‐standing goal of evolutionary biology is to understand how paleoclimatic and geological events shape the geographical distribution and genetic structure within and among species. Using a diverse set of markers (cuticular hydrocarbons, mitochondrial and nuclear gene sequences, microsatellite loci), we studied Reticulitermes grassei and R. banyulensis, two closely related termite species in southwestern Europe. We sought to clarify the current genetic structure of populations that formed following postglacial dispersal from refugia in southern Spain and characterize the gene flow between the two lineages over the last several million years. Each marker type separately provided a fragmented picture of the evolutionary history at different timescales. Chemical analyses of cuticular hydrocarbons and phylogenetic analyses of mitochondrial and nuclear genes showed clear separation between the species, suggesting they diverged following vicariance events in the Late Miocene. However, the presence of intermediate chemical profiles and mtDNA introgression in some Spanish colonies suggests ongoing gene flow. The current genetic structure of Iberian populations is consistent with alternating isolation and dispersal events during Quaternary glacial periods. Analyses of population genetic structure revealed postglacial colonization routes from southern Spain to France, where populations underwent strong genetic bottlenecks after traversing the Pyrenees resulting in parapatric speciation.
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Affiliation(s)
- Thomas Lefebvre
- Institut de Recherche sur la Biologie de l'Insecte UMR CNRS 7261 UFR Sciences et Techniques Université François Rabelais 37200 Tours France; Present address: Ynsect R&D dpt Genopole 391058 Evry France
| | - Edward L Vargo
- Department of Entomology 2143 TAMU Texas A&M University College Station Texas 77843-2143 USA
| | - Marie Zimmermann
- Institut de Recherche sur la Biologie de l'Insecte UMR CNRS 7261 UFR Sciences et Techniques Université François Rabelais 37200 Tours France
| | - Simon Dupont
- Institut de Recherche sur la Biologie de l'Insecte UMR CNRS 7261 UFR Sciences et Techniques Université François Rabelais 37200 Tours France
| | - Magdalena Kutnik
- Institut de Recherche sur la Biologie de l'Insecte UMR CNRS 7261 UFR Sciences et Techniques Université François Rabelais 37200 Tours France; FCBA - Institut technologique Dpt Biologie et Préservation du BoisAllée de Boutaut BP 227 33000 Bordeaux France
| | - Anne-Geneviève Bagnères
- Institut de Recherche sur la Biologie de l'Insecte UMR CNRS 7261 UFR Sciences et Techniques Université François Rabelais 37200 Tours France
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Abstract
Why do most animals live solitarily, while complex social life is restricted to a few cooperatively breeding vertebrates and social insects? Here, we synthesize concepts and theories in social evolution and discuss its underlying ecological causes. Social evolution can be partitioned into (a) formation of stable social groups, (b) evolution of helping, and (c) transition to a new evolutionary level. Stable social groups rarely evolve due to competition over food and/or reproduction. Food competition is overcome in social insects with central-place foraging or bonanza-type food resources, whereas competition over reproduction commonly occurs because staying individuals are rarely sterile. Hence, the evolution of helping is shaped by direct and indirect fitness options and helping is only altruism if it reduces the helper's direct fitness. The helper's capability to gain direct fitness also creates within-colony conflict. This prevents transition to a new evolutionary level.
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Affiliation(s)
- Judith Korb
- Department of Evolutionary Biology & Ecology, University of Freiburg, D-79104 Freiburg, Germany;
| | - Jürgen Heinze
- Institute of Zoology/Evolutionary Biology, University of Regensburg, D-93040 Regensburg, Germany;
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Darrouzet E, Labédan M, Landré X, Perdereau E, Christidès JP, Bagnères AG. Endocrine control of cuticular hydrocarbon profiles during worker-to-soldier differentiation in the termite Reticulitermes flavipes. JOURNAL OF INSECT PHYSIOLOGY 2014; 61:25-33. [PMID: 24374106 DOI: 10.1016/j.jinsphys.2013.12.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 12/12/2013] [Accepted: 12/18/2013] [Indexed: 06/03/2023]
Abstract
The social organization of termites, unlike that of other social insects, is characterized by a highly plastic caste system. With the exception of the alates, all other individuals in a colony remain at an immature stage of development. Workers in particular remain developmentally flexible; they can switch castes to become soldiers or neotenics. Juvenile hormone (JH) is known to play a key role in turning workers into soldiers. In this study, we analyzed differences in cuticular hydrocarbon (CHC) profiles among castes, paying particular attention to the transition of workers to soldiers, in the subterranean termite species Reticulitermes flavipes. CHCs have a fundamental function in social insects as they serve as cues in inter- and intraspecific recognition. We showed that (1) the CHC profiles of the different castes (workers, soldiers, nymphs and neotenics) are different and (2) when workers were experimentally exposed to a JH analog and thus induced to become soldiers, their CHC profiles were modified before and after the worker-presoldier molt and before and after the presoldier-soldier molt.
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Affiliation(s)
- E Darrouzet
- University of Tours, IRBI UMR CNRS 6172, parc de Grandmont, 37200 Tours, France.
| | - M Labédan
- University of Tours, IRBI UMR CNRS 6172, parc de Grandmont, 37200 Tours, France
| | - X Landré
- University of Tours, IRBI UMR CNRS 6172, parc de Grandmont, 37200 Tours, France
| | - E Perdereau
- University of Tours, IRBI UMR CNRS 6172, parc de Grandmont, 37200 Tours, France
| | - J P Christidès
- University of Tours, IRBI UMR CNRS 6172, parc de Grandmont, 37200 Tours, France
| | - A G Bagnères
- University of Tours, IRBI UMR CNRS 6172, parc de Grandmont, 37200 Tours, France
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10
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Bourguignon T, Šobotník J, Sillam-Dussès D, Jiroš P, Hanus R, Roisin Y, Miura T. Developmental pathways of Psammotermes hybostoma (Isoptera: Rhinotermitidae): old pseudergates make up a new sterile caste. PLoS One 2012; 7:e44527. [PMID: 23028554 PMCID: PMC3444481 DOI: 10.1371/journal.pone.0044527] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 08/03/2012] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Ergonomic efficiency is in termites maximized by task partitioning among specialized castes. The isopteran caste systems can be classified as either (i) linear, when tasks are performed by pluripotent immatures (pseudergates), retaining the ability to develop into winged imagoes or (ii) bifurcated, with the presence of a true worker caste, which diverges early and permanently from the sexual (nymph/alate) line. PRINCIPAL FINDINGS Here, we report on the ontogenetic potentialities of the highly polymorphic sand termite Psammotermes hybostoma. Beside numerous pluripotent pseudergates, constituting the main work force, some larger non-feeding apterous immatures, also occur. These individuals are unable to proceed to the winged imago stage, but store large amounts of fat and also give rise to large soldiers. Soldiers therefore originate from a wide range of apterous instars, consequently being highly polymorphic. CONCLUSIONS The caste system of P. hybostoma is essentially linear, as in other basal Rhinotermitidae, but is distinguished by the late bifurcation leading to large apterous immatures. Because these large worker-like individuals deviate late and do not perform worker tasks, they cannot be considered homologous to the true workers of Termitidae and advanced Rhinotermitidae, but they provide a novel example of the evolution of sterile immatures in termites.
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Affiliation(s)
- Thomas Bourguignon
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan
- Evolutionary Biology and Ecology, Université Libre de Bruxelles, Brussels, Belgium
| | - Jan Šobotník
- Institute of Organic Chemistry and Biochemistry, Prague, Czech Republic
- Czech University of Life Sciences, Faculty of Forestry and Wood Sciences, Prague, Czech Republic
| | - David Sillam-Dussès
- Institute of Organic Chemistry and Biochemistry, Prague, Czech Republic
- Laboratoire Écologie et Évolution, Université Pierre et Marie Curie, Paris, France
- IRD, UMR 211 BIOEMCO, IBIOS, Bondy, France
- Laboratoire d’Ethologie Expérimentale et Comparée, Université Paris 13, Villetaneuse, France
| | - Pavel Jiroš
- Institute of Organic Chemistry and Biochemistry, Prague, Czech Republic
| | - Robert Hanus
- Evolutionary Biology and Ecology, Université Libre de Bruxelles, Brussels, Belgium
- Institute of Organic Chemistry and Biochemistry, Prague, Czech Republic
| | - Yves Roisin
- Evolutionary Biology and Ecology, Université Libre de Bruxelles, Brussels, Belgium
| | - Toru Miura
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan
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Korb J, Buschmann M, Schafberg S, Liebig J, Bagnères AG. Brood care and social evolution in termites. Proc Biol Sci 2012; 279:2662-71. [PMID: 22398169 DOI: 10.1098/rspb.2011.2639] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Cooperative brood care is assumed to be the common driving factor leading to sociality. While this seems to be true for social Hymenoptera and many cooperatively breeding vertebrates, the importance of brood care for the evolution of eusociality in termites is unclear. A first step in elucidating this problem is an assessment of the ancestral condition in termites. We investigated this by determining the overall level of brood care behaviour across four termite species that cover the phylogenetic diversity of the lower termites. Brood care was low in the three species (all from different families) that had an ancestral wood-dwelling lifestyle of living in a single piece of wood that serves as food and shelter. In the fourth species, a lower termite that evolved outside foraging, brood care was more common. Together with data for higher termites, this suggests that brood care in termites only becomes important when switching from a wood-dwelling to a foraging lifestyle. These results imply that early social evolution in termites was driven by benefits of increased defence, while eusociality in Hymenoptera and cooperative breeding in birds and mammals are primarily based on brood care.
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Affiliation(s)
- Judith Korb
- Behavioural Biology, University of Osnabrueck, Barbarastrasse11, 49076 Osnabrueck, Germany.
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Competition between invasive and indigenous species: an insular case study of subterranean termites. Biol Invasions 2010. [DOI: 10.1007/s10530-010-9906-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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