Meeting Abstract

P2.106  Saturday, Jan. 5  Reproductive Skew in a hybrid population of swordtail fish SQUIRE, M K*; ROSENTHAL, G G; Texas A&M University; Texas A&M University squiremk@gmail.com

Understanding the myriad processes by which speciation may occur is a central goal in evolutionary biology. Natural hybrid zones, where the genomes of two different species collide, afford researchers a unique opportunity to study how species are maintained and how new species may develop. In this study, adults from a wild hybridizing population of the live-bearing fish, Xiphophorus malinche and X. birchmanni, were collected from a pool of the Aquazarca river drainage in southeastern Mexico during the dry season. Embryos were dissected out of females for parentage analysis using microsatellites. After genotyping offspring, dams, and males from the population, Cervus 3.0 will be used to determine number of fathers per brood, and to determine which males are the most likely sires. Reproductive skew will then be determined and correlated with morphological characteristics of the males to obtain a measure of pre-copulatory sexual selection in this hybrid population. We aim to compare this to previous paternity analyses and behavioral experiments done in both parental species of fish in order to get a better idea of how sexual selection and mating systems vary when two species come together in a hybrid zone.