Mechanisms of inbreeding avoidance in the one-piece drywood termite Neotermes chilensis

Abstract

Inbreeding depression refers to a decrease in fitness components in the offspring of closely related sexual pairs. Given the disadvantages of inbreeding depression, it is of interest to study the mechanisms involved in its avoidance, particularly in social insects. In termites, colonies are founded by dispersing individuals. Two types of mechanisms may account for inbreeding avoidance: indirect mechanisms that occur before the dispersing individuals come into contact (sex-biased production at colony level, sex-biased emergence timing, dispersal, and sex-biased dispersal), and an active mechanism (kin recognition) that occurs when dispersing individuals come into contact. We have used ecological, behavioral and genetic approaches to study the mechanisms of inbreeding avoidance along the complete process of colony foundation by Neotermes chilensis, i.e., from the production of dispersing individuals in the colony to the production of siblings by the newly formed reproductive pair. This is the first report to address both indirect and active mechanisms of inbreeding avoidance in the same study, in the same termite species, and through the complete process of colony foundation. The results show that dispersal is the main indirect mechanism of inbreeding avoidance and that kin recognition is unlikely as an active mechanism of inbreeding avoidance.