Role of the fat body in the regulation of host-seeking behaviour in the mosquito,Aedes aegypti

Following a blood meal that initiates oöcyte development, the host-seeking behaviour of Aedes aegypti mosquitoes is inhibited by a haemolymph-borne factor that is released in response to a humoral signal from a vitellogenic ovary. This inhibition is accompanied by a decrease in the sensitivity of the peripheral lactic acid receptors. Implantation of corpora allata, medial neurosecretory cells, or terminal abdominal ganglia from blood-fed donors could not induce the inhibition in sugar-fed recipients. However, fat body transplanted from blood-fed into sugar-fed females suppressed host-seeking behaviour as well as the sensitivity of lactic acid receptors, suggesting that the source of the behavioural inhibitor is the fat body. Resting-stage ovaries from other mosquito species inhibited host-seeking after the A. aegypti host was fed on blood only if the fat body was activated by the donor ovary.