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Pyenson BC, Rehan SM. Gene regulation supporting sociality shared across lineages and variation in complexity. Genome 2024; 67:99-108. [PMID: 38096504 DOI: 10.1139/gen-2023-0054] [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] [Indexed: 01/25/2024]
Abstract
Across evolutionary lineages, insects vary in social complexity, from those that exhibit extended parental care to those with elaborate divisions of labor. Here, we synthesize the sociogenomic resources from hundreds of species to describe common gene regulatory mechanisms in insects that regulate social organization across phylogeny and levels of social complexity. Different social phenotypes expressed by insects can be linked to the organization of co-expressing gene networks and features of the epigenetic landscape. Insect sociality also stems from processes like the emergence of parental care and the decoupling of ancestral genetic programs. One underexplored avenue is how variation in a group's social environment affects the gene expression of individuals. Additionally, an experimental reduction of gene expression would demonstrate how the activity of specific genes contributes to insect social phenotypes. While tissue specificity provides greater localization of the gene expression underlying social complexity, emerging transcriptomic analysis of insect brains at the cellular level provides even greater resolution to understand the molecular basis of social insect evolution.
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Affiliation(s)
| | - Sandra M Rehan
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada
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2
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Beshers SN. Regulation of division of labor in insects: a colony-level perspective. CURRENT OPINION IN INSECT SCIENCE 2024; 61:101155. [PMID: 38109969 DOI: 10.1016/j.cois.2023.101155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 12/06/2023] [Accepted: 12/13/2023] [Indexed: 12/20/2023]
Abstract
Studies of division of labor have focused mainly on individual workers performing tasks. Here I propose a shift in perspective: colonies perform tasks, and task performance should be evaluated at the colony level. I then review studies from the recent literature from this perspective, on topics including evaluating task performance; specialization and efficiency; flexibility and task performance; response threshold models; and variation in behavior arising from diverse sensory experiences and learning. The use of specialized workers is only one of a variety of strategies that colonies may follow in performing tasks. The ability of colonies to produce consistent responses and to compensate for changes in the labor pool supports the idea of a task allocation system that precedes specialization. The colony-level perspective raises new questions about how tasks are done and the strategies used to improve colony task performance.
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Affiliation(s)
- Samuel N Beshers
- Department of Entomology, University of Illinois at Urbana-Champaign, 505 South Goodwin Avenue, Urbana, IL 61801, USA.
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Walton A, Toth AL. Nutritional inequalities structure worker division of labor in social insects. CURRENT OPINION IN INSECT SCIENCE 2023; 58:101059. [PMID: 37230413 DOI: 10.1016/j.cois.2023.101059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 05/16/2023] [Accepted: 05/20/2023] [Indexed: 05/27/2023]
Abstract
Eusocial insect societies are fundamentally non-egalitarian. The reproductive caste 'wins' in terms of resource accumulation, whereas non-reproductive workers 'lose'. Here, we argue that the division of labor among workers is also organized by nutritional inequalities. Across vastly different social systems and a variety of hymenopteran species, there is a recurrent pattern of lean foragers and corpulent nest workers. Experimental manipulations confirm causal associations between nutritional differences, associated molecular pathways, and behavioral roles in insect societies. The comparative and functional genomic data suggest that a conserved toolkit of core metabolic, nutrient storage, and signaling genes has evolved to regulate the social insect division of labor. Thus, the unequal distribution of food resources can be considered a fundamental organizing factor in the social insect division of labor.
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Affiliation(s)
- Alexander Walton
- Biological Sciences, University of Alberta, Edmonton AB T6G 2E9, Canada
| | - Amy L Toth
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50014 USA.
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Veenstra JA. Evolution of a Cockroach Allergen into the Major Protein of Termite Royal Jelly. Int J Mol Sci 2023; 24:10311. [PMID: 37373456 DOI: 10.3390/ijms241210311] [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: 03/30/2023] [Revised: 05/23/2023] [Accepted: 06/16/2023] [Indexed: 06/29/2023] Open
Abstract
Termites live in colonies, and their members belong to different castes that each have their specific role within the termite society. In well-established colonies of higher termites, the only food the founding female, the queen, receives is saliva from workers; such queens can live for many years and produce up to 10,000 eggs per day. In higher termites, worker saliva must thus constitute a complete diet and therein resembles royal jelly produced by the hypopharyngeal glands of honeybee workers that serves as food for their queens; indeed, it might as well be called termite royal jelly. However, whereas the composition of honeybee royal jelly is well established, that of worker termite saliva in higher termites remains largely unknown. In lower termites, cellulose-digesting enzymes constitute the major proteins in worker saliva, but these enzymes are absent in higher termites. Others identified a partial protein sequence of the major saliva protein of a higher termite and identified it as a homolog of a cockroach allergen. Publicly available genome and transcriptome sequences from termites make it possible to study this protein in more detail. The gene coding the termite ortholog was duplicated, and the new paralog was preferentially expressed in the salivary gland. The amino acid sequence of the original allergen lacks the essential amino acids methionine, cysteine and tryptophan, but the salivary paralog incorporated these amino acids, thus allowing it to become more nutritionally balanced. The gene is found in both lower and higher termites, but it is in the latter that the salivary paralog gene got reamplified, facilitating an even higher expression of the allergen. This protein is not expressed in soldiers, and, like the major royal jelly proteins in honeybees, it is expressed in young but not old workers.
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Affiliation(s)
- Jan A Veenstra
- INCIA UMR 5287 CNRS, Université de Bordeaux, 33600 Pessac, France
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Yaguchi H, Suzuki S, Kanasaki N, Masuoka Y, Suzuki R, Suzuki RH, Hayashi Y, Shigenobu S, Maekawa K. Evolution and functionalization of vitellogenin genes in the termite Reticulitermes speratus. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2023; 340:68-80. [PMID: 35485990 DOI: 10.1002/jez.b.23141] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 03/22/2022] [Accepted: 04/08/2022] [Indexed: 12/16/2022]
Abstract
Eusociality has been commonly observed in distinct animal lineages. The reproductive division of labor is a particular feature, achieved by the coordination between fertile and sterile castes within the same nest. The sociogenomic approach in social hymenopteran insects indicates that vitellogenin (Vg) has undergone neo-functionalization in sterile castes. Here, to know whether Vgs have distinct roles in nonreproductive castes in termites, we investigated the unique characteristics of Vgs in the rhinotermitid termite Reticulitermes speratus. The four Vgs were identified from R. speratus (RsVg1-4), and RsVg3 sequences were newly identified using the RACE method. Molecular phylogenetic analysis supported the monophyly of the four termite Vgs. Moreover, the termites Vg1-3 and Vg4 were positioned in two different clades. The dN/dS ratios indicated that the branch leading to the common ancestor of termite Vg4 was under weak purifying selection. Expression analyses among castes (reproductives, workers, and soldiers) and females (nymphs, winged alates, and queens) showed that RsVg1-3 was highly expressed in fertile queens. In contrast, RsVg4 was highly expressed in workers and female nonreproductives (nymphs and winged adults). Localization of RsVg4 messenger RNA was confirmed in the fat body of worker heads and abdomens. These results suggest that Vg genes are functionalized after gene duplication during termite eusocial transition and that Vg4 is involved in nonreproductive roles in termites.
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Affiliation(s)
- Hajime Yaguchi
- Graduate School of Science and Engineering, University of Toyama, Gofuku, Toyama, Japan.,Tropical Biosphere Research Center, University of the Ryukyus, Nishihara, Japan.,Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo, Japan
| | - Shogo Suzuki
- Graduate School of Science and Engineering, University of Toyama, Gofuku, Toyama, Japan
| | - Naoto Kanasaki
- Graduate School of Science and Engineering, University of Toyama, Gofuku, Toyama, Japan
| | - Yudai Masuoka
- Graduate School of Science and Engineering, University of Toyama, Gofuku, Toyama, Japan.,Institute of Agrobiological Sciences, NARO (National Agriculture and Food Research Organization), Tsukuba, Japan
| | - Ryutaro Suzuki
- Graduate School of Science and Engineering, University of Toyama, Gofuku, Toyama, Japan
| | - Ryouhei H Suzuki
- Graduate School of Science and Engineering, University of Toyama, Gofuku, Toyama, Japan
| | | | - Shuji Shigenobu
- NIBB Research Core Facilities, National Institute for Basic Biology, Okazaki, Japan
| | - Kiyoto Maekawa
- Faculty of Science, Academic Assembly, University of Toyama, Gofuku, Toyama, Japan
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Resource sharing is sufficient for the emergence of division of labour. Nat Commun 2022; 13:7232. [PMID: 36433975 PMCID: PMC9700737 DOI: 10.1038/s41467-022-35038-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 11/16/2022] [Indexed: 11/26/2022] Open
Abstract
Division of labour occurs in a broad range of organisms. Yet, how division of labour can emerge in the absence of pre-existing interindividual differences is poorly understood. Using a simple but realistic model, we show that in a group of initially identical individuals, division of labour emerges spontaneously if returning foragers share part of their resources with other group members. In the absence of resource sharing, individuals follow an activity schedule of alternating between foraging and other tasks. If non-foraging individuals are fed by other individuals, their alternating activity schedule becomes interrupted, leading to task specialisation and the emergence of division of labour. Furthermore, nutritional differences between individuals reinforce division of labour. Such differences can be caused by increased metabolic rates during foraging or by dominance interactions during resource sharing. Our model proposes a plausible mechanism for the self-organised emergence of division of labour in animal groups of initially identical individuals. This mechanism could also play a role for the emergence of division of labour during the major evolutionary transitions to eusociality and multicellularity.
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