Condition-dependent interaction between mating success and competitive fertilization success in Drosophila melanogaster

Dietary restriction during development can affect adult body size and condition. In many species, larger (high-condition) males gain higher mating success through male-male competition and female choice, and female condition can affect the extent of both female mate choice and male investment in courtship or ejaculates. However, few studies have examined the joint effects and interplay of male and female condition during both the pre- and the post-copulatory phases of sexual selection. We therefore manipulated the larval diet of male and female Drosophila melanogaster to study how body size variation in both sexes biases competitive outcomes at different reproductive stages, from mating to paternity. We did not find a difference in mate preference or mating latency between females of different conditions, nor any interaction between male and female conditions. However, large males were more successful in gaining matings, but only when in direct competition, whereas mating latencies were...