Data from: Neuroendocrine correlates of sex-role reversal in barred buttonquails

Sex differences in brain structure and behaviour are well documented among
vertebrates. An excellent model exploring the neural mechanisms of sex
differences in behaviour is represented by sex-role-reversed species. In
the majority of bird species, males compete over access to mates and
resources more strongly than do females. It is thought that the
responsible brain regions are therefore more developed in males than in
females. Because these behaviours and brain regions are activated by
androgens, males usually have increased testosterone levels during
breeding. Therefore, in species with sex-role reversal, certain areas of
the female brain should be more developed or steroid hormone profiles
should be sexually reversed. Here, I studied circulating hormone levels
and gene expression of steroid hormone receptors and aromatase in a
captive population of barred buttonquails (Turnix suscitator). While
females performed courtship and agonistic behaviours, there was no
evidence for sexually reversed hormone profiles. However, I found
female-biased sex differences in gene expression of androgen receptors in
several hypothalamic and limbic brain regions that were already in place
at hatching. Such sex differences are not known from non-sex-role-reversed
species. These data suggest that increased neural sensitivity to androgens
could be involved in the mechanisms mediating sex-role-reversed
behaviours.