Mother-offspring correlation and mate-choice copying behavior in guppies

One broad, well-accepted definition of cultural transmission is the spreading of information by social learning or copying. The tendency to copy the action of others, however, may itself be a heritable trait. Here we measured the narrow-sense heritability of the tendency of female guppies (Poecilia reticulata) to copy the mate choice of other females. Thirty-two female guppies were tested on their tendency to copy the mate choice of same-sized models. These 32 females produced a total of 83 female offspring, who upon reaching 11 weeks of age, were tested on their tendency to mate-choice copy. A significant positive correlation was found between the absolute time that mothers and their daughters spent near a male chosen by another (model) female. However, the correlation between the time that mothers and daughters spent near the male not chosen by the model female, and the correlation between mothers and daughters with respect to the proportion of time spent near a male chosen by a model, were not significant. Our data do not suggest that the tendency to copy the mate choice of others has a significant heritability. If it did, we would expect mothers and daughters to show similar scores on the proportion of time spent near a male chosen by a model, which is not the case. Instead, what appears to be a heritable trait is the absolute amount of time that a female spends near a male chosen by a model. Females in our study could do one of three things: spend time near a male chosen by a model, spend time near a male not chosen by a model, or spend time in the "neutral zone". It appears that mothers and daughters behave similarly with respect to the first of these, but divide up their time between the second and third quite differently, thus producing the results we record here.