Mating experience and juvenile hormone enhance sexual signaling and matingin male Caribbean fruit flies

Young mated male Caribbean fruit flies [Anastrepha suspensa (Loew)] have gr eater sexual prowess than their virgin counterparts. After mating for the f irst time, 6- to ir-day-old males released twice as much sex pheromone and acquired another mate in less than half the time required by virgin males o f the same age. Mass spectroscopic analysis of extracts of hemolymph from m ated and Virgin 7-day-old males resulted in identification of juvenile horm one III bisepoxide and juvenile hormone III in a ratio of 2.5:1. Extracts f rom mated males contained 3-fold more juvenile hormone than did extracts fr om virgins. Enhancement of sexual signaling, pheromone release, and mating was induced by topical application of juvenile hormone, methoprene, or feno xycarb. Newly enclosed adult males treated with juvenoids engaged in sexual signaling, released pheromone, and mated at significantly earlier ages tha n control males. We conclude that juvenile hormone mediated a positive feed back system that imparted a competitive advantage, guaranteeing that males who mated at an early age would out-compete virgins of the same age for mat ing opportunities. Additionally. the results support the hypothesis that ju venile hormone is a pivotal hormone coordinating the development of sexual signaling and reproductive maturity in these flies.