SIMILARITY IN RESPONSE TO DIAZINON, DIELDRIN AND PYRETHRUM EXTRACT BY ALLATECTOMISED AND NORMAL HOUSE-FLIES (MUSCA DOMESTICA L.).

Abstract

Allatectomy of newly emerged house-flies (Musca domesticaL.) prevents maturation of the ovaries, and experiments were done to find whether this affected the sensitivity of the flies to insecticides.The apparatus and operational procedure for removing the complex comprising the corpus allatum and corpora cardiaca are described.Females of a diazinon-resistant strain (SKA) were allatectomised less than 12 hr. after emergence, and when three days old their sensitivity to diazinon, dieldrin and pyrethrum extract was tested by topical application. Approximately equal numbers of intact females were tested simultaneously, and untreated controls of both kinds of flies were included in every test. The failure of the ovaries to mature in allatectomised flies was confirmed by examination of a majority of the operated flies that lived for four days, and normal development of the ovaries of intact flies was similarly confirmed.The results showed that there was no difference in sensitivity between allatectomised and normal flies. It is concluded that allatectomy does not affect susceptibility to the insecticides used. Since earlier work had shown that a 9- to 18-fold increase in resistance to diazinon takes place during the period from emergence to the third day afterwards, it is further concluded that this increase is unaffected by allatectomy and the failure of the ovaries to mature.