Genetic caste determination in termites: out of the shade but not from Mars

Crozier, Ross H.; Schlüns, Helge

doi:10.1002/bies.20732

Cited by 8 publications

(3 citation statements)

References 38 publications

(32 reference statements)

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“…In the honeybee, a specific diet and, more generally, the nutritional status influence caste determination and behavioural development [ 23 , 24 ]. The role of environment in caste determination of termites has been assumed to be omnipotent compared with exclusively genetic effects (but see [ 25 , 26 ]). Secondary reproductives develop in response to external stimuli, such as environmental factors (e.g.…”

Section: Introductionmentioning

confidence: 99%

The role of the glucose-sensing transcription factor carbohydrate-responsive element-binding protein pathway in termite queen fertility

et al. 2016

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Termites are among the few animals that themselves can digest the most abundant organic polymer, cellulose, into glucose. In mice and Drosophila, glucose can activate genes via the transcription factor carbohydrate-responsive element-binding protein (ChREBP) to induce glucose utilization and de novo lipogenesis. Here, we identify a termite orthologue of ChREBP and its downstream lipogenic targets, including acetyl-CoA carboxylase and fatty acid synthase. We show that all of these genes, including ChREBP, are upregulated in mature queens compared with kings, sterile workers and soldiers in eight different termite species. ChREBP is expressed in several tissues, including ovaries and fat bodies, and increases in expression in totipotent workers during their differentiation into neotenic mature queens. We further show that ChREBP is regulated by a carbohydrate diet in termite queens. Suppression of the lipogenic pathway by a pharmacological agent in queens elicits the same behavioural alterations in sterile workers as observed in queenless colonies, supporting that the ChREBP pathway partakes in the biosynthesis of semiochemicals that convey the signal of the presence of a fertile queen. Our results highlight ChREBP as a likely key factor for the regulation and signalling of queen fertility.

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Section: Introductionmentioning

confidence: 99%

The role of the glucose-sensing transcription factor carbohydrate-responsive element-binding protein pathway in termite queen fertility

et al. 2016

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“…As for most social insects, the process of caste differentiation is likely mediated by environmental cues that trigger physiological restrictions on development [ 20 , 21 ]. However, genetic differences too could influence an individual termite’s differentiation into one caste or another [ 22 ], and do so along either pathway. For R. flavipes , colonies are typically headed by a pair of outbred primary reproductives [ 23 ], but in invasive habitats the species tends toward a unicolonial structure with spatially diffuse nests, low aggression and rampant neotenic reproduction with potentially hundreds of egg-laying nymphs [ 24 ].…”

Section: Introductionmentioning

confidence: 99%

Differential Selection on Caste-Associated Genes in a Subterranean Termite

Radford

Chen

Chernyshova

et al. 2022

Insects

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Analyzing the information-rich content of RNA can help uncover genetic events associated with social insect castes or other social polymorphisms. Here, we exploit a series of cDNA libraries previously derived from whole-body tissue of different castes as well as from three behaviourally distinct populations of the Eastern subterranean termite Reticulitermes flavipes. We found that the number (~0.5 M) of single nucleotide variants (SNVs) was roughly equal between nymph, worker and soldier caste libraries, but dN/dS (ratio of nonsynonymous to synonymous substitutions) analysis suggested that some of these variants confer a caste-specific advantage. Specifically, the dN/dS ratio was high (~4.3) for genes expressed in the defensively specialized soldier caste, relative to genes expressed by other castes (~1.7–1.8) and regardless of the North American population (Toronto, Raleigh, Boston) from which the castes were sampled. The populations, meanwhile, did show a large difference in SNV count but not in the manner expected from known demographic and behavioural differences; the highly invasive unicolonial population from Toronto was not the least diverse and did not show any other unique substitution patterns, suggesting any past bottleneck associated with invasion or with current unicoloniality has become obscured at the RNA level. Our study raises two important hypotheses relevant to termite sociobiology. First, the positive selection (dN/dS > 1) inferred for soldier-biased genes is presumably indirect and of the type mediated through kin selection, and second, the behavioural changes that accompany some social insect urban invasions (i.e., ‘unicoloniality’) may be detached from the loss-of-diversity expected from invasion bottlenecks.

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“…In termites, a major group of social insects, caste development is highly plastic and environmental signals are thought to be critical for caste determination (Wilson, 1971;Miura, 2001;Miura et al, 2003;Scharf et al, 2003;Scharf et al, 2005;Scharf et al, 2007;Matsuura et al, 2010;Hartke & Baer, 2011). In recent years, however, genetic influences on caste determination have been reported in some social insects (reviewed in Crozier & Schluns, 2008;Smith et al, 2008b;.…”

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confidence: 99%

Neotenic reproductives influence worker caste differentiation in the termite Reticulitermes speratus (Isoptera; Rhinotermitidae)

Hayashi¹,

Miyata²,

Kitade³

et al. 2013

Sociobiology

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Division of labor among castes in social insect colonies increases ergonomic efficiency and colony-level fitness, and has played a key role in the ecological success of social insects. Knowledge of the factors that regulate castes is important for understanding adaptive social organization. Our previous study on the termite Reticulitermes speratus demonstrated that the presence of a pair of nymphoid reproductives during development affected offspring caste ratios. In the present study, we investigated further the influence of individual neotenics on offspring caste ratios. Parthenogenetically-produced offspring were reared in worker-tended experimental colonies with the addition of different forms (nymphoid or ergatoid) and numbers of neotenics, and compared the caste ratios of the offspring between the different experimental treatments. We found that all offspring in worker-only tended colonies became nymphs, while a proportion of offspring in colonies with a single neotenic (with the exception of male ergatoids) differentiated into workers. These results show offspring caste ratios are influenced by the presence of single female ergatoids, single female and male nymphoids, while they remain unaffected by the presence of male ergatoids.

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Genetic caste determination in termites: out of the shade but not from Mars

Cited by 8 publications

References 38 publications

The role of the glucose-sensing transcription factor carbohydrate-responsive element-binding protein pathway in termite queen fertility

The role of the glucose-sensing transcription factor carbohydrate-responsive element-binding protein pathway in termite queen fertility

Differential Selection on Caste-Associated Genes in a Subterranean Termite

Neotenic reproductives influence worker caste differentiation in the termite Reticulitermes speratus (Isoptera; Rhinotermitidae)

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