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

Abstract

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.

Threat of Subterranean Termites Attack in the Asian Countries and their Control: A Review

“…There are three types of reproductives in a termite colony: the primary, secondary and tertiary reproductives. Recently, Hayashi et al (2013) found that the termite colony Reticulitermes speratus that lost the primary reproductive castes will form the secondary reproductive castes (neotenic reproductive) within four to seven days. In the colony there is a main colony, where the main queen lives and satellite units, in which secondary reproductive are laying eggs.…”

Regulatory Mechanisms Underlying the Differentiation of Neotenic Reproductives in Termites: Partial Release From Arrested Development

“…The differentiation of neotenic reproductives is controlled by genetic, maternal, and environmental factors. In Reticulitermes speratus and several other species, for instance, genetic, and maternal factors influenced by sex-linked genetic mechanisms, i.e., the asexual queen succession (AQS) system, are responsible for the neotenic differentiation (Hayashi et al, 2007;Matsuura et al, 2009;Matsuura et al, 2018;Hellemans et al, 2019), although environmental factors during the postembryonic development also affect the caste fate determination (Hayashi et al, 2007(Hayashi et al, , 2013. In contrast, environmental factors during postembryonic development, such as social interactions between reproductives and nonreproductive castes, are also determinant force for the neotenic differentiation (Lüscher, 1974;Shimoji et al, 2017;Sun et al, 2017;Masuoka et al, 2021).…”