Long-sperm precedence and other cryptic female choices in Drosophila melanogaster

Females that mate multiply make postmating choices about which sperm fertilize their eggs (cryptic female choice); however, the male characteristics they use to make such choices remain unclear. In this study, we sought to understand female sperm use patterns by evaluating whether Drosophila melanogaster females adjust sperm use (second male paternity) in response to four main factors: male genotype, male courtship effort, male pheromone alteration, and male postmating reproductive morphology. Our experiment was replicated across four different D. melanogaster lines, in a full factorial design, including a pheromone manipulation in which second males were perfumed to resemble heterospecific (D. yakuba) males. We found that females prefer longer sperm—regardless of mating order—in almost all contexts; this observed pattern of ‘long-sperm precedence’ is consistent with female postmating choice of high-fitness male traits. Nonetheless, we also found that this general preference can be plas..., , , # Long-sperm precedence and other cryptic female choices in *Drosophila melanogaster*

How do females make choices about which sperm will fertilize their eggs? In this study, we assess four geographically diverse *Drosophila melanogaster* lines to show that females strongly prefer long sperm—a pattern consistent with female preference for high-fitness males. In addition, we perfumed males to show that females can adjust this general preference based on other factors, including pheromones. Because this adjustment occurs between genotypically identical males, it is entirely female-mediated.

## Data

Our behavioral and morphological data are composed of 10 data files. 'Courtship.csv' and 'paternity.csv' contain our raw mating and paternity data. This mating data was restructured for our remating analysis in the 'remating.csv' file. Morphology data are summarized in 'morphology.csv'. Some morphology data was restructured for making figures, including 'SR_testis_length.csv' (seminal recept...