INTERACTION BETWEEN DIET AND HORMONES ON VITELLOGENIN LEVELS IN THE HOUSEFLY, MUSCA-DOMESTICA

Vitellogenin levels in houseflies maintained on sucrose did not increase after pulse-feeding protein if the corpus allatum-cardiacum (CA-CC) complex was removed or if the flies were allatectomized within 6 h of emergence. Vitellogenin levels did increase, however, after pulse-feeding protein to ovariectomized flies or to insects that were allatectomized at 48 h, but the levels were significantly lower than in the unoperated protein-fed controls. Ecdysteroid levels did not increase after pulse-feeding protein to sucrose-fed flies if the CA-CC complex or ovaries had been removed or if the flies were allatectomized at 6 h. Flies that had the CA-CC complex and ovaries removed (- OV) did not have any detectable vitellogenin on either the sucrose or protein diets. Treatment of these - CA-CC - OV sucrose-fed flies with either methoprene (JHA) or 20-hydroxyecdysone (20-HE) did not result in vitellogenin production, but treating them with both hormones did. Flies on the protein diet produced vitellogenin after treatment with JHA or 20-HE either alone or together. Diet appears to be modulating the action of OH and 20-HE on the induction of vitellogenin production in Musca.