Heritability and repeatability of behavioural attributes affecting foraging success and fitness in water striders

Abstract

Abstract. Heritabilities and repeatabilities are presented for various behavioural attributes affecting foraging performance and fitness in Aquarius (Gerris) remigis (Heteroptera: Gerridae) females. These behavioural attributes were patch choice, foraging success, capture accuracy, and measures of mobility, activity, skittishness and aggressiveness. Most heritabilities were not significantly different from zero, which may be related to the low sample size. Conclusions as to the potential of direct selection on behaviour in this species were consequently limited. In contrast, with a few exceptions (capture accuracy, foraging success), most repeatabilities were significant and at times high (range=0·22-0·79), indicating consistent, stereotypical individual behaviour. The life history or reproductive state of the daughter generation individuals significantly affected the magnitude of the repeatabilities as well as the mean values of many of the variables (notably mobility and aggressiveness), the latter in a manner consistent with field observations. This indicates that the state of the organism affects the general environmental variance, thus contributing to the discrepancies between the repeatabilities and the heritabilities obtained. It is suggested that common physiological processes (e.g. hormones) may underlie several of the behavioural attributes examined, resulting in possible pleiotropic effects and constraints on selection in a heterogeneous environment. It is further suggested that field studies of selection on behavioural attributes may be a more fruitful approach in this species, whose suitability for genetic analysis is limited.