Sex affects the network of covariances between cognitive, behavioral, and physiological traits in guppies

Cognitive variance has been documented across many species. It may stem from constraints imposed by the covariation among different traits. We hypothesized that sex could contribute to cognitive variance by affecting the traits’ covariation. By applying a network analysis in the guppy (Poecilia reticulata), a fish with marked sexual dimorphism, we found that males and females differed along a fast-slow continuum, with males exhibiting higher metabolism, higher activity levels, faster learning, and lower cognitive flexibility. Moreover, we found more covarying traits in males compared to females (12 versus 7). Pairwise associations involving cognitive traits significantly differed in the covariance networks of the two sexes and were stronger in males. Various traits, including learning and cognitive flexibility, had different influences in the covariation network between males and females. Cognitive traits are embedded in a complex, sex-dependent web of covariation, which may be important for the evolution and maintenance of cognitive variance.