Artificial selection on mating competitiveness of Anastrepha ludens for sterile insect technique application

Abstract

The sterile insect technique (SIT) has been applied successfully for the control of several fruit fly species of economic importance. In species with lek mating systems, as in the Mexican fruit fly, Anastrepha ludens (Loew) (Diptera: Tephritidae) – where the variance in male mating success is high, males have to compete with other males, and where wild females are highly selective – the success of SIT depends on the sexual competitiveness of mass-reared sterile males. However, mass-rearing conditions result in selection of sexual behavioral traits that differ from wild flies, reducing mating competitiveness of sterile flies and SIT efficiency. Artificial selection in mass-rearing colonies, based on male mating success, represents an alternative to improve the sexual performance of sterile males. Here, we evaluated the effect of selection of A. ludens mass-reared males based on their mating competitiveness. Two modes of selection were compared, one single selection event on parental flies, and continuous selection along four consecutive generations. For the offspring of each treatment in each generation, we evaluated male mating success, its association with post-copulatory behavior through female remating inhibition, and life-history traits that are key for mass-rearing, such as immature survival and reproduction. Field cage mating tests revealed that wild males were more competitive than mass-reared males (selected and unselected). Although no significant differences were found between mass-reared selected and non-selected males, in the fourth generation males from the selected colonies performed better than males from the non-selected colonies and their mating competitiveness was similar to that of wild males. No consistent differences were observed in mating latency, copulation duration, or ability to inhibit female remating. Survival and fecundity decreased with increasing rearing generations, except in the colony with continuous selection where fecundity and fertility increased.