Mating of the Amazon racerunner (Ameiva praesignis) (Squamata, Teiidae) in Panama

Abstract

Polygyny is common among lizards, and sexual dimorphism in coloration and size influences sexual selection by females. Courtship and copulation include ritualized behaviors such as chasing, cloacal rubbing, and head bobbing, observed especially in the family Teiidae. Ameiva praesignis, a diurnal Neotropical lizard, inhabits various terrestrial habitats in Central America, and juveniles have bright blue tails that they lose as they mature. During a mating event, the male and female were observed to remain motionless during copulation, followed by a dominant posture by the male, while another smaller male watched them without intervening. This behavior suggests that males guard females to reduce competition and increase reproductive success. Marked sexual dimorphism was noted, with larger, more corpulent males and intense coloration. The courtship and mating behaviors of A. praesignis are like those of A. ameiva, perhaps suggesting that they are characters that are fixed at the genus level. Although mating events are common, in some species they are poorly documented, highlighting the influence of size and coloration on sexual selection.