Role Change

389 Words2 Pages
Many teleost fishes are sequential hermaphrodites meaning that their gonadal function and sexual role can change during the life of the individual. This ability to change sex is an evolutionary adaptive strategy for the fish. It enables the fish population to carry on and repopulate quickly in the wake of a disturbance. The way this sex change is induced is through social interactions and cues. A fish that begins as a female and transitions into a male is called protogynous. The opposite reversal is called a protandrous species. Sex and role change is caused by a social cue such as an imbalance in the typical male to female ratio. Fish are very aware of this ratio and the density of their population. Generally, there are more females in a teleost population than males because males have to freedom and stamina to fertilize many females in their lifetime. If something were to remove an alpha male from a social group, usually the dominant female of the group will undergo…show more content…
The hypothalamus is first to receive the stimuli that will induce sex change. Once initiated, the hypothalamus releases GnRH to stimulate the pituitary to release gonadotropins (Gth I and II in teleost) which then make the journey down the HPG axis to the gonads. The gonads produce testosterone which is the converted to either estrogen or 11-Ketotestosterone by aromatase or 11β-hydroxylase, respectively. Both of these hormones play a key role in gonadal sex differentiation and sexual behavior. If the levels of these two hormones are manipulated in a clinical setting, the sex change process can be induced, stopped, or even reversed. These results lean toward the idea that the production and levels of these sex steroids are vital to how social cues are transduced into gonadal

More about Role Change

Open Document