EFFECT OF METHYLTESTOSTERONE ON THE FORMATION OF THE CANESTRINI'S ORGAN IN FEMALE COBITIS TAENIA BILINEATA CANESTRINI (COBITIDAE OSTEICHTHYES)

Abstract

SUMMARY The treatment of female or female phase specimens of Cobitis taenia bilineata Canestrini with 100 μg of methyltestosterone/litre of aquarium water induced the formation of Canestrini's organ and a thickening of the 2nd ray of the pectoral fin. These experimental results, correlated with observations in nature, indicate that Canestrini's organ is a hormonally controlled secondary sex character which develops fully in males and male phase individuals of this partially protandrous hermaphrodite species.