64.1 Jan. 7 Experimental manipulation of sexual selection and the evolution of locomotor performance in Drosophila pseudoobscura ROBERTS, SP*; CRUDGINGTON, HS; SNOOK, RR; Univ of Nevada Las Vegas; Univ of Sheffield; Univ of Sheffield email@example.com
Sexual selection typically yields sexual dimorphism in traits related to mate competition and mate choice, and among such traits in highly motile species is locomotor performance. Here, we subjected the naturally promiscuous fruit fly Drosophila pseudoobscura to enforced monogamy, standard levels of promiscuity, and elevated opportunities for promiscuity in four replicate lines. After over twenty generations of these selective regimes, we tested whether experimental variation in the intensity of sexual selection led to evolutionary changes in walking speed and flight capacity (as determined by the ability to alter trajectory during free-fall). Contrary to expectations, walking speeds of males from the elevated promiscuity lines were slightly slower than those of males from standard promiscuity and enforced monogamy lines, while males from the promiscuity lines had poorer flight performance than males from the enforced monogamy lines. The largest effect in the study was a 22% decrease in the walking speed of females from the enforced monogamy lines relative to females from the standard promiscuity and elevated promiscuity lines. Female flight performance did not significantly vary among the selection lines. These results suggest that increased sexual selection and competition in male D. pseudoobscura in turn select for enhanced locomotor performance in females.