A study of tactical and sexual dimorphism in cognition with insights for sexual conflict

The sexes may have different optima in cognitive traits due to differences in life history strategies and the expense of investing in metabolically costly brain tissue. However, given genetic correlations, each sex could be constrained from reaching its cognitive optimum due to intralocus sexual conflict. We compared learning performance of two male alternative reproductive tactics and females from known genotypes (both sire and dam) in the livebearing fish Xiphophorus multilineatus. We predicted that females’ learning performance would align with the learning performance of their sire’s genotype due to genetic correlation of cognitive traits. Using a classical conditioning assessment (associating a flashing light with a food reward), we detected mating tactic dimorphism in learning performance, with the behaviourally plastic sneaker males outperforming the behaviourally fixed courter males. Unexpectedly, females sired by the faster-learning sneaker males performed significantly worse t...