Sex differences in aggressive intensities and brain steroids during status resolution in a sex changing fish, Lythrypnus dalli.

For vertebrates living in social hierarchies, the neuroendocrine system regulates temporal aspects of aggressive interactions during status establishment. In teleost fishes, the sex steroids 17β-estradiol (E) and 11-ketotestosterone (KT), and the glucocorticoid, cortisol (CORT) are associated with aggression in distinct phases of their life history. Bluebanded gobies, Lythrypnus dalli, exhibit bidirectional sexual plasticity by responding to changes in their social structure by escalating aggression associated with neural changes that precede gonadal reorganization to the opposite sex.