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Social control of male sexual maturation in the swordtail characin, Corynopoma riisei
Author(s) -
Bushmann P. J.,
Burns J. R.
Publication year - 1994
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.1994.tb01204.x
Subject(s) - biology , juvenile , sexual maturity , zoology , fish <actinopterygii> , adult male , endocrinology , positive correlation , medicine , ecology , fishery
The presence of adult male Corynopoma riisei was found to inhibit the maturation of juvenile males. Males in a conspecific community tank took longer to mature and did so at increasingly slower rates compared to isolated controls, providing a positive correlation between size and time of maturational onset. The inhibitory effect increased with greater numbers of adult males. The first males to mature did so at accelerated rates, suggesting positive as well as negative control. Tanks in which adult males were removed as soon as maturation was complete showed an intermediate pattern, with no lengthening of the maturational time course but an increase in standard length. Histological examination revealed immature males with lengths greater than the control range; these appear to represent inhibited animals. Both the testes and pituitary gonadotropic zone of these males appeared undeveloped, arguing for inhibition at least at the hypothalamic level. This phenomenon has also been described in poeciliids The presence of a similar complex mechanism in two distant groups of fishes suggests convergent evolution. It also suggests that this phenomenon may be physiologically possible for a wide range of fish species.