Ecdysteroid titers in mated and unmated Drosophila melanogaster females

Radioimmunoassay was used to determine ecdysteroid titers in mated or unmat ed Drosophila melanogaster females. Whole-body ecdysteroid titers increase after mating and this response is more pronounced after 12-24 hours than it is immediately after mating. In one experiment, females were mated to tran sgenic males deficient in accessory gland proteins to test whether these pe ptides mediate the observed increase in female whole-body ecdysteroid titer s. Females mated to such transgenic males do not show a pronounced increase in whole-body ecdysteroid titers. The effect of mating on female hemolymph ecdysteroid titers was also investigated. Hemolymph ecdysteroid titers dec rease after mating. The ecdysteroid titer change in the hemolymph may resul t from yolk protein uptake of ecdysteroids into developing vitellogenic ooc ytes as a consequence of male accessory gland protein stimulation of female oocyte maturation and yolk protein synthesis following mating. (C) 1999 El sevier Science Ltd. All rights reserved.