Genetic Analysis of Predatory Efficiency in Natural and Laboratory Made Hybrids of Poeciliopsis (Pisces: Poeciliidae)

Abstract

AbstractMultiple hybridization events between females of Poeciliopsis monacha and males of P. lucida have produced a genetic diversity of all-female biotypes in Sonora, Mexico. All-females depend on the sperm of their sexual ancestors. Strong competition among all-females and their coexistent sexual host take place. The frozen niche-variation model was proposed to explain how such coexistence is possible and how the genetic diversity of all-female biotypes arose. According to this model, the hybrids have multiple origins, freeze and replicate unique genotypes, and produce phenotypic differences with reduced ecological overlap with one another and their sexual ancestors. The objective of the study was to test whether differences in predatory efficiency of all-females are 'frozen' from the sexual ancestor which possessed phenotypic diversity for that behavioural trait. I investigated predatory efficiency in nine strains of Poeciliopsis (P. monacha, two natural hybrids, and six laboratory made hybrids). First, I analysed the variation in average performances of each strain for time spent in capture and handling of two prey species (Artemia salina and Daphnia magna). Second, I offered both prey simultaneously to test if preference affects the average time spent to handle prey. Preference for prey species was analysed using the order of capture as reference. Handling time and prey preference differed among laboratory made hybrids, supporting frozen niche-variation model assumptions.