Abstract
Sexually mature male and female spiny damselfish, Acanthochromis polyacanthus (Pomacentridae) were introduced to resident fish of both sexes in paired encounter trials and the effect on activity, agonistic behaviour and plasma levels of testosterone (T) and 11-ketotestosterone (11-KT) in males, and T and 17β-estradiol (E2) in females, and cortisol in both sexes was determined. Introduced males showed suppressed levels of T in the presence of both resident males and females, whereas resident males showed elevated T in response to introduced males but not females. Plasma 11-KT levels were unchanged in either resident or introduced males. Resident males showed increased activity in the presence of males but not females. Resident females showed an increase in activity when paired with introduced females and greater aggressive behaviour towards females than males. There were no differences in plasma hormone levels in either resident or introduced female fish. Plasma cortisol levels were low in all fish and stress effects did not appear to account for differences in T levels in males. The results of the present study show that elevations in plasma T levels in resident male spiny damselfish are associated only with male presence but that suppression of T in introduced fish occurs irrespective of the sex of the resident. In contrast resident females, which show stronger evidence of aggressive behaviour do not show changes in plasma androgen levels. This suggests that aggressive behaviour in male and female fishes may be mediated by different endocrine pathways.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.