Linking mating preferences to sexually selected traits and offspring viability: good versus complementary genes hypotheses

Abstract

Indirect fitness benefits hypotheses suggest that offspring of preferred mates should exhibit greater survival or reproductive success. For example, good genes hypotheses propose that female mating preferences are mediated by secondary sexual traits because they honestly reflect the ability to pass on genes that will enhance offspring survival or reproduction. Conversely, complementary genes hypotheses propose that mating preferences are mediated by complementary genes because they enhance offspring viability. While these two research traditions are not strict alternatives and both may operate simultaneously, they have never been tested together. Here we explore the multiple potential underlying factors influencing mating preference evolution in Jamaican field crickets, Gryllus assimilis. After evaluating female preferences for randomly selected males, we tested whether preferred males differed from nonpreferred males in their body size, relative mass or mate attraction signals. We then mated females to their preferred or nonpreferred partners and tested offspring viability. Results revealed: (1) females preferred larger males, (2) larger females oviposited more eggs, (3) neither morphology nor mate attraction signalling explained variation in offspring viability, and (4) mating with a preferred partner did not enhance offspring viability. Overall, in our current study population, cricket mate preferences were inconsistent with complementary genes and good genes hypotheses for indirect fitness benefits. Our current research explores whether male secondary sexual traits honestly reflect the ability to pass on genes that enhance offspring reproduction.