Knowledge Bank

Females of the Northern house mosquito, Culex pipiens, transmit West Nile virus to humans and animals throughout the summer. However, during the fall and winter females do not bite or transmit disease but survive the winter in a hibernation-like state called diapause. The male mosquitoes do not survive the winter, but instead mate with females in the fall who store their sperm inside of specialized organs called spermathecae. Diapause in female mosquitoes is a seasonal response that occurs in mosquitoes once they are exposed to short-day, winter-like conditions. Female mosquitoes that enter diapause cease blood feeding and thereby halt disease transmission. Although males do not survive the winter, they change their seminal fluids in response to seasonal cues. Additionally, mated females of the yellow fever mosquito, Aedes aegypti, live longer than virgin females. We therefore hypothesized that seasonal changes in the seminal fluids of males would influence the survival of the female mosquitoes. To determine whether the seasonal conditions the males were exposed to affected female longevity, long and short day-reared females were allowed to mate with long or short day-reared males and female survival was monitored weekly. Additionally, the longevity of virgin long day and short day-reared females was also measured. In both long and short-day conditions, we found that virgin females lived longer than mated females. Furthermore, while the photoperiod of the male mosquitoes did not influence the survival of female mosquitoes reared under long-day, summer-like conditions, short day-reared females that mated with short day-reared females lived significantly longer than those mated with long day-reared males. These findings lay the foundation for future work to uncover new ways that we can control this important disease vector.