The programming of circadian flight-activity in relation to mating and the gonotrophic cycle in the mosquito, Aedes aegypti


Dr M. D. R. Jones, Imperial College, Silwood Park, Ascot, Berks. SL5 7PY.


ABSTRACT. The circadian flight activity of female Aedes aegypti (L.) changes after insemination and during the course of the gonotrophic cycle. Virgin females attain a high level of spontaneous activity within 3–4 days of adult emergence; in LD 12:12 there are peaks of activity at the beginning and end of the light phase. Inseminated females are less than 20% as active as virgins, but exhibit a similar daily pattern. After blood-feeding, inseminated females become almost totally inactive for about 48h and then show a unimodal pattern of activity which is consistent with oviposition behaviour; after oviposition they revert to the basic inseminated pattern and level of activity. Blood-fed virgin females continue to show a high level of spontaneous activity. It is suggested that insemination has the general effect of raising the threshold for activity and that it is necessary before blood-fed females can switch to the gravid behaviour programme. Blood-fed uninseminated females thus continue with behaviour which will maximize the probability of insemination.