Meeting Abstract

S7-2.3  Sunday, Jan. 6  The Role of Circadian Clock Genes in the Overwintering Diapause of the Northern House Mosquito, Culex pipiens MEUTI, Megan E.*; DENLINGER, David L.; The Ohio State University; The Ohio State University

Diapause is an arrested state of development that allows insects and other arthropods to survive adverse seasonal conditions, such as the limited food availability and lower temperatures that are associated with winter. Temperate insects enter diapause in response to the short day lengths of late summer and early fall. However the molecular mechanisms by which insects measure day length is unknown. Several researchers have hypothesized that the circadian clock, which provides insects with information on the time of day, might also be involved in measuring day length. To determine whether the circadian clock is involved in initiating the overwintering diapause of the Northern House Mosquito, Culex pipiens, we used RNA interference to knock down several core circadian clock genes (period, timeless, Cryptochrome2 and Cycle). We confirmed RNA knock down using qPCR, and assessed the diapause status of RNAi-treated females by measuring the length of their egg follicles (large follicles = non-diapause; small follicles = diapause). We found that knocking down the clock gene Cycle, a positive regulator of the circadian clock, had no effect on diapause initiation. However when negative regulators of the circadian clock (period, timeless and Cryptochrome2) were knocked down, female mosquitoes that had been reared under diapause inducing conditions failed to enter diapause. Our results suggest that a functioning circadian clock is essential for initiating the overwintering diapause of these mosquitoes.