A comparison of the reproductive strategies of three species of Dysdercus from Africa (Hemiptera, Pyrrhocoridae)

Summary

Reproductive strategies have been investigated for three species of Dysdercus from Africa, D. intermedius, D. cardinalis and D. nigrofasciatus. Reproductive parameters were measured for each species on individuals cultured in the laboratory.

D. cardinalis is associated more with herbaceous than with arboreal host plants and is intermediate in body size. It tended to have the least age at first reproduction, reproduced most frequently, and layed the smallest clutches on average, spreading relatively high amounts of parental investment in more clutches than the other two species. It also laid the greatest number of clutches and eggs in a lifetime.

D. intermedius specializes on arboreal host plants, and is the largest of the three species. It had the greatest age at first reproduction, reproduced less frequently than D. cardinalis, and layed the largest clutches. Its parental investment over time declined earlier than that of D. cardinalis. D. intermedius layed the least number of clutches in a lifetime, but its lifetime gross reproduction was intermediate in magnitude.

D. nigrofasciatus has the widest diet breadth, and is the smallest in body size. Its age at first reproduction was similar to that of D. cardinalis, but D. nigrofasciatus reproduced least frequently, laying relatively large clutches. It was similar to D. intermedius in its pattern of parental investment over time, and essentially layed the same number of clutches in a lifetime as the latter species, although its lifetime gross reproduction was the smallest.

It is suggested that the reproductive strategies of the three species might have evolved as adaptations to selection events in the niches of the immature stages.