Maternal care of a single offspring in the dung beetleKheper nigroaeneus: the consequences of extreme parental investment

Abstract

The nesting biology of Kheper nigroaeneus, a large diurnal ball-rolling dung beetle, was studied in Mkuzi Game Reserve, South Africa. On each nesting occasion a female reared a single offspring from egg to adult in an underground nest. During the first two weeks of nesting the female fed on the outside of the brood ball, reducing its volume by 60%. The larva required only 17% of the ball for development. Female K. nigroaeneus remained physiologically prepared to develop a second egg and hence initiate a new nest, if the first was unsuccessful, for about three weeks after oviposition. Thereafter they resorbed the second and any subsequent oocytes. Offspring survival was between 58% and 84% for egg to adult. The sexual strategies of both sexes are discussed, with particular consideration given to the question of why the male deserts the nest before oviposition.