Life-history traits and the mating system of an Australian water strider, Tenagogerris euphrosyne

Abstract

The hemipteran infraorder Gerromorpha (the semiaquatic bugs, or water striders) has been used extensively as a model taxon in evolutionary biology and ecology. Most studies have focused on North American and European species while there is a paucity of comparable data on the gerromorphs of Africa and Australia. In a series of laboratory experiments we explore patterns of ontogenetic development, foraging and mating behaviour in Tenagogerris euphrosyne (Kirkaldy), a medium-sized water strider distributed along the east coast of Australia. Our study revealed that T. euphrosyne nymphs passed through five instars before adulthood, but that mortality and rates of cannibalism were high. Foraging and mating trials revealed that the foraging success of adult males (but not females) was positively correlated with mating success. Observations indicated that T. euphrosyne exhibits a Type I water strider mating behaviour: mating followed a brief period of struggling by the female, after which males were able to ride on a female’s back for extended periods. Females gained direct fertility benefits from mating and were able to store sperm and lay fertilised eggs (albeit a reduced quantity) for several weeks even in the absence of males.