Courtship behaviour in the Knife livebearer Alfaro cultratus (Cyprinodontiformes: Poeciliidae).

The mating behaviour of the Knife livebearer Alfaro cultratus is described in detail. During "Rubbing", the male swims to a position above the female, and gently moves down repeatedly touching the dorsal part of female head with the pelvic fin tips. This courtship behaviour constitutes the first report of a pelvic fin male-female contact during mating in poecilids. Based on preliminary evidence, I propose that a sensory bias mechanism could mediate the evolution of signal design/mate choice in this species, which should be tested in further studies. This article is protected by copyright. All rights reserved.