Female mate preference and offspring fitness in the melon fly

The influence of female mate preference on the fitness components of offspring was studied in the melon fly, Dacus cucurbitae. Adult flies were allowed to mate under two experimental treatments. In one treatment, 100 females and 100 males were allowed to mate freely in a cage (cage-mating). In the other treatment, a single female was allowed to mate with a single male in a small chamber (chamber-mating). Viability in the immature stages was not different between two treatments. The developmental speed of female offspring in the cage-mating treatment was faster than that in the chamber-mating treatment. The wing length of offspring of both sex in the cage-mating treatment was also larger than that in the chamber-mating treatment. These results were considered to support 3-trait handicap models of the evolution of female mate preference.