The role of the pelvic fins in the copulatory act of certain poeciliid fishes. American Museum novitates ; no. 1509

Abstract

"The role of the male pelvic fins in the copulatory act of Lebistes reticulatus, Platypoecilus maculatus, and Xiphophorus hellerii has been studied experimentally. Males with one pelvic fin removed appear to be able to transfer sperm to a female as readily as intact control fish. Males with both fins removed are strongly handicapped in this respect, although they may eventually adjust themselves to this condition and transfer sperm without the aid of pelvic fins. The pelvic fins of mature males appear to have three possible functions during copulation: (1) as a supporting mechanism for the gonopodium when the latter is brought forward and to the side during the swinging, thrusting, and copulatory behaviors in courtship, (2) as a mechanism to aid the gonopodium in forming an enclosure for the passage of spermatophores, and (3) as a supplementary part of the ejaculatory mechanism for the release of spermatophores during copulation"--P. 13.