Biology subjects

Peckenpaugh, B.

Publications and source records attributed to Peckenpaugh, B..

3 recordsLinked to original sources

bioRxiv2024

Females drive postmating reproductive trait evolution across Drosophila species, but not via remating rate

While traits that contribute to premating sexual interactions are known to be wildly diverse, much less is known about the diversity of postmating (especially female) reproductive traits and the mechanisms shaping this diversity. To assess the rate, pattern, and potential drivers of postmating reproductive trait evolution, we analyzed male and female traits across up to 30 Drosophila species within a phylogenetic comparative framework. In addition to postmating reproductive morphology (e.g., sperm length, reproductive tract length and mass), we also quantified mating behaviors including female remating rate--a common proxy for the strength of postmating sexual selection. We found evidence for strong coevolution between male and female postmating traits (specifically sperm length and sperm storage organ size). However, remating rate was not associated with the rate of evolution or exaggeration of either male or female postmating reproductive morphology, once phylogenetic relatedness was accounted for. We infer that female-mediated and intersexual selection predominantly drive the evolution of our postmating morphological traits, including via divergent male and female interests in controlling paternity. In comparison, remating rate has a complex and likely secondary role in shaping this evolution, in part because this trait can be both a driver and a product of postmating selection.

evolutionary biology↗

bioRxiv2024

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 plastically altered by females in response to effects including perfuming treatment; this differential female sperm use is between otherwise identical males, and therefore solely female-mediated. Furthermore, our finding that females exercise choice using diverse criteria suggests a possible mechanism for the maintenance of variation in sexually selected male traits. Teaser textHow 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.

evolutionary biology↗

bioRxiv2021

Testing potential mechanisms of conspecific sperm precedence in Drosophila pseudoobscura

Drosophila pseudoobscura females that co-occur with sister species D. persimilis show elevated fertilization by conspecific sperm when they mate with both a heterospecific and a conspecific male. This phenomenon, known as conspecific sperm precedence (CSP), has evolved as a mechanism to avoid maladaptive hybridization with D. persimilis. In this study, we assessed pericopulatory (during mating) and postcopulatory (after mating) traits in crosses with sympatric or allopatric D. pseudoobscura females and conspecific or heterospecific males to evaluate potential mechanisms of CSP in this system. We observed shorter copulation duration in crosses with sympatric females, but found no difference in quantity of sperm transferred or female reproductive tract toxicity between sympatry and allopatry. Our data also support the hypothesis that parasperm, a short, sterile sperm morph, can protect fertile eusperm from the D. pseudoobscura female reproductive tract, though it is unclear how this might affect patterns of sperm use in sympatry vs. allopatry. Overall, these results suggest that copulation duration could potentially contribute to the elevated CSP observed in sympatry.

evolutionary biology↗