Egg-laying and foam-beating in Leptodactylus fuscus (Anura, Leptodactylidae)

Abstract

Species of the Leptodactylus fuscus group lay their eggs in foam nests in underground chambers the males excavate. However, little is known about the interactions between males and females while egg-laying. We recorded egg-laying behavior in Leptodactylus fuscus. Observations were possible because the chambers walls were partially damaged (small holes). Within the chamber, the male holds the female in an axillary amplexus. In a typical sequence of egg-releasing/foam-beating, the male makes alternate movements of legs in a series of kicks. After a bout of foam-beating the male releases the female removing his arms from her axils. When freed by the male, the female turned a little for a new bout of beating, being seized in an axillary amplexus again. In the species of Leptodactylus of the fuscus group the lack of thumb asperities and spines may be related to their terrestrial egg-laying behavior and to the stability the couples have within the chamber.