Introduction
Social behavior is a set of interactions among individuals within a species and is displayed in a wide spectrum of forms, and eusociality represents the most intimate and complex degree of social organization. Eusociality is defined by the presence of distinct reproductive and non-reproductive castes, overlapping generations, and cooperative care for the brood within a colony (Engels 1990; Kocher and Paxton 2014). Reproductives (kings and queens) and non-reproductives (workers or soldiers) in the colonies are differentiated morphologically, physiologically, and behaviorally (Wheeler 1907; Wilson 1971; Robinson et al. 1991; Harvell 1994; Sherman et al. 1994; Gräff et al. 2007; Begna et al. 2012; Seeley 2014). Although most well-characterized eusocial species are termites and hymenopteran insect species such as honeybees and ants, eusociality has been reported in several other insect, non-insect, and even vertebrate species (Sherman et al. 1994; Duffy et al. 2000). Although taxonomically rare, eusocial insect species exhibit great ecological importance, as approximately 50% of the world insect biomass is comprised of eusocial insect species (Wilson 1971; Kocher and Paxton 2014).
Eusocial insects offer an appealing opportunity to uncover mechanisms underlying how the social environment can alter the rate of organismal aging (Parker 2010; Lucas and Keller 2014). Due to their extraordinary caste-related lifespan differences, their plasticity in the rate of aging, and their contradiction of the usual fecundity/lifespan trade-off, eusocial insects provide an excellent model system for research on aging (Chapuisat and Keller 2002; Parker 2010; Lucas et al. 2017; Corona et al. 2019; Kohlmeier et al. 2019). This article proposes the possible role of telomerase and telomere biology in life-span regulation as a reproduction strategy of animal species.