Role of guava volatiles on Anastrepha fraterculus male sexual display and pheromone release

BACHMANN GUILLERMO; MARIA TERESA VERA; TEAL PETER; RUIZ M JOSEFINA; M LAURA JUAREZ; CLADERA JORGE; DIEGO FERNANDO SEGURA; FERNANDEZ PATRICIA CARINA

Congreso; 2nd Meeting of the Latin American Association of Chemical Ecology; 2012

The South American fruit fly Anastrepha fraterculus is a fruit crop pest in Argentina and neighboring countries with a complex courtship in which males cluster in leks and release a sex pheromone while performing sexual displays (Lima et al. 2001). Although preexposure of males to certain fruit volatiles has been shown to increase their mating success (Vera et al. 2010), the mechanism associated to this phenomenon is unknown. Here, we evaluated the hypothesis that this increase in mating success is mediated by an increase in pheromone emission and/or a change in the associated sexual displays. A. fraterculus males preexposed to guava volatiles were individually offered to virgin females together with not exposed males. Under such conditions, females chose one partner and males were assigned into one of four possible categories: according to treatment (guava exposed or not exposed) and mating success (successful or unsuccessful). On the following day, we collected volatiles emitted by each male type in groups of ten individuals and registered behavioral parameters of the sexual display. Male volatiles were adsorbed in SuperQ filters and desorbed with dichloromethane to be analyzed by gas chromatography. Pheromonal compounds were identified by standards. The results show that the intensity of the sexual display positively correlates to the amount of released pheromone. Successful males performed a more intense sexual display (and released more pheromone) than unsuccessful ones. Preexposure to guava volatiles increased the probability of male mating success. This phenomenon appears to be mediated by an increase in the proportion of males able to release pheromone to levels that conferred a greater acceptance by females. Further studies should look into differences in short distance cues as the cuticular composition of males after exposure.