Non-repeatable mate choice by male sailfin mollies, Poecilia latipinna, in a unisexual-bisexual mating complex

Most studies of repeatability examine female mate choice, but male mate choice may have significant evolutionary consequences when males of a sexual species are sexually parasitized by heterospecific gynogenetic females as is the case for sailfin mollies, Poecilia latipinna. Amazon mollies, Poecilia formosa, are all female gynogens that require sperm from P. latipinna for initiation of embryogenesis, but inheritance is strictly maternal. We examined repeatability and consistency of male mate choice for female sailfin versus Amazon mollies in a series of 4 experiments. We measured male association preference for 1) size-matched female sailfin versus Amazon mollies, 2) smaller female sailfin mollies versus larger Amazon mollies, and 3) larger female sailfin mollies versus smaller Amazon mollies. We also examined 4) actual male mate choice for size-matched sailfin versus Amazon mollies. Male mate preference was not repeatable in any of our studies, and male sailfin mollies were consistent in their mate preference for conspecific females over heterospecific females only when the conspecific female was larger than the Amazon and when males could actually mate with females of both species. In all experiments, males that showed the highest conspecific preference also showed the most consistency in their preference across the 2 days of testing. The lack of repeatability of male mate preference may contribute to the persistence of Amazon mollies.