Tuesday, December 14, 2010
Grand Exhibit Hall (Town and Country Hotel and Convention Center)
In most insects, a single mating is usually sufficient to supply females with enough sperm to fertilize a lifetime production of eggs. Despite sufficient sperm, many female insects mate repeatedly in their lifetime. This may be due, in part, to having mated with a small male that did not supply enough sperm to fertilize a lifetime of eggs, or to females discriminating against potential mates based on body size. Such discrimination could occur during courtship, copulation, or post-copulation. It is thought that female northern corn rootworms mate only once in their lifetime. We report on the mating capacity, longevity, and fecundity of female northern corn rootworm in relation to body size. For mating, we paired combinations of large and small males and females in Petri dishes. Weight of large and small individuals was greater than 1 SD above and below the mean. Average sized males and females were also paired for comparison. All individuals were obtained as pupae and reared to adults. Males were used only once. We observed all pairs for at least two hours and successful mating pairs until copulation was completed. Females that did not copulate initially and all males were discarded. Females that copulated with their initial partner were caged individually with ample food, water, and an oviposition dish and placed in growth chambers. At weekly intervals until death, the mated females were provided with fresh oviposition dishes and the opportunity to mate with an average sized male. We report the multiple mating, longevity, and fecundity data by male and female size category.