Inversion polymorphism and circadian flight activity in the mosquito<i>Anopheles stephensi</i>List. (Diptera, Culicidae)

Abstract

Abstract Circadian flight activity in Anopheles stephensi List. has been investigated using the acoustic aotograph technique. In alternating 12 h light: 12 h dark (50 or 200 lx), both sexes are active during the dark period, with peaks of activity following light-off and light-on. Cyclical activity persists in constant dark and is inhibited and reset by prolonging the light period. There are small differences between the carriers of the alternative chromosomal arrangements 2R+ ( +/+) and 2Rb (b/b) and between the sexes. In +/+ females the period of the cycle in constant dark is approximately half-an-hour longer and, in LD 12:12, there is less activity at light-on than in both sexes of b/b or in +/+ males. The +/+ males appear to be less susceptible to the inhibitory effect of prolonging the light period, although the cycle is reset.