ARS | Publication request: Fecundity and longevity in female Northern Corn Rootworm relative to body size and copulation frequency

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 20, 2011
Publication Date: N/A

Technical Abstract: A single mating usually provides female insects with enough sperm to fertilize a lifetime of eggs; however, many females mate repeatedly during their lifetime. It is believed that female northern corn rootworm (NCR) mate only once throughout their life. To investigate, we paired combinations of large, small, and average sized male and female NCR in Petri dishes. Copulating females were caged individually with plenty of food, water, and an oviposition dish and placed in growth chambers. Each week until death, females were provided with oviposition dishes and the opportunity to mate with an average sized male. Of 201 copulating females, 63 mated twice and five mated three times, but neither the proportion of females that copulated more than once nor their age at first copulation varied with pair type. Females tended to re-mate at a younger age when originally mated to small males. We found no differences in longevity or in total and viable egg numbers with pair type. Females mating more than once lived longer than singly mated females. These females also laid more eggs and viable eggs. Should greater longevity of multiply mated females and thus their greater fecundity occur under field conditions, then reproductive success of these females should exceed that of singly mated females. Female corn rootworms resistant to Bt corn could enhance offspring survival by maximizing fertilization of their eggs by Bt resistant males. More information on the reproductive biology of corn rootworms is needed to fully understand the evolution of Bt resistance.