The Effects of the Operational Sex Ratio on Female and Male Mate Choice in the Jamaican Field Cricket (Gryllus assimillis)

Abstract

The operational sex ratio (OSR; ratio of sexually available females to sexually available males) is a social environment that greatly influences mate choice, but how it concurrently affects mate choice in both sexes in species with mutual mate choice remains poorly understood. In this thesis, I experimentally investigated the potential influence of variation in the OSR (male-biased, even sex ratio, and female-biased) on which sex is the choosiest in the Jamaican field cricket, Gryllus assimilis. I also tested the consistency of individual mate choice as quantified using a dichotomous mate choice test and a full-interaction choice test under different OSR levels. OSR did not influence female or male mate choice, but it did influence how potential mates interact. Females and males did not consistently choose the same mate between the two types of mate choices tests, and OSR did not affect the likelihood of consistently choosing the same mate.iii