Testing theories of sexual selection in decorated crickets (Gryllodes sigillatus)

Abstract

Question: Do females choose males according to their level of acoustic sexual activity, fluctuating asymmetry, size, condition or do they select for genetic compatibility according to relatedness? What are the relative strengths of selection on these traits and what might be the benefit of the choice – large nuptial gifts, heritable attractiveness or quality? Organism: Laboratory colony of decorated crickets (Gryllodes sigillatus). Methods: Behavioural trial of female preference on male traits, multivariate logistic regression of male traits on female preference, and heritability estimation of the traits with an animal model. Results: Female attraction strongly discriminated in favour of certain male courtship call rates. None of the other potential cues, such as size-dependent traits, fluctuating asymmetry or relatedness were involved in sexual selection. In addition, no evidence of benefits of the attraction was found. However, if the cost of choice for females is low, then the potential genetic benefits outweighing it might be smaller than what can be estimated with this data set. Moreover, the signal itself is a strong species-specific signal that facilitates mate location and helps to prevent maladaptive hybridization. Thus, the signal itself may be considered a benefit without any additional correlated benefits.