Egg mass destroying behaviour of the female giant water bugLethocerus deyrollei Vuillefroy (Heteroptera: Belostomatidae)

Abstract

After being laid on emergent aquatic vegetation, the egg masses ofLethocerus deyrollei are brooded by the male. In laboratory studies, females were observed to destroy egg masses and ingest the fluid of eggs. Brooding males fought with these attackers at first, but then gave up the defense and mated with them. After destroying the egg masses, females laid new ones at the same sites on the same night or the following one, and males brooded the new offspring. The population density of this species is very low. Most males engage in brooding and cease to become acceptable mates after most of the females lay the first egg masses. It is costly for females to search out free males in the aquatic vegetation. By destroying egg masses, however, individual females can gain new mates with little exertion and can make them brood their own offspring. Furthermore, the survival of their own offspring increases with the elimination of their competitors.