Males can’t afford to be choosy: Male reproductive investment does not influence preference for female size in Limia (Poeciliidae)

Abstract

Reproductive investment was initially thought to be the key selective force behind male mate preference for female characters, like size or ornamentation (i.e., the preference by males for certain females). Yet, evidence of polygynous species, where male reproductive investments are often inexpensive compared to those of females, have also been described to possess male preference. Our study aims to understand how reproductive investment influences the selection of choosy males in polygynous systems using two species of livebearing fishes varying in reproductive investment: Limia perugiae, in which males invest heavily into reproduction, and L. zonata in which males invest minimally into reproduction. We hypothesized that male reproductive investment when combined with fecundity selection will favour the evolution of male mate preference and thereby lead to males that invest heavily into reproduction being choosier than males that invest minimally. When male Limia were exposed to two females simultaneously, one from the small size class and one from the large size class, L. zonata chose large females over small ones, whereas L. perugiae allocated the same amount of time regardless of female size class. Although we fail to find support for our original hypotheses, our study highlights the need for a more thorough examination of non-model species like Limia. We suggest future studies analyse reproductive investment as it interacts with cryptic choice, multiple sensory cues as well as expand comparisons to multiple Limia species, especially those endemic to Cuba, Grand Cayman, and Jamaica.