Dermatophagy in caecilians (Amphibia, Gymnophiona): a behavioral, morphological and biochemical study

Abstract

Among vertebrates, the amphibians show the larger diversity of reproductive modes, including varied forms of parental care, which is very common in the Gymnophiona. Our group recently described (Nature, 440, 926-929, 2006) in the oviparous African caecilian Boulengerula taitanus a new type of parental care, in which the young feed on the female's skin (dermatophagy). In contrast, the viviparous species retain the young in the uterus and feed them with a uterine secretion ("uterine milk"). Both dermatophagy and uterine feeding occur in the Brazilian caecilians, such as the oviparous Siphonops annulatus and the viviparous Chthonerpeton indistinctum. Amphibian integument is highly complex and plays a number of vital roles. In function of the dermatophagy, the female's skin during parental care undergoes morphological and biochemical alterations that have previously been studied at histological and histochemical levels. It is probable that the toxic function of the cutaneous glands is alterated during this phase. On the other hand, very little is known about the oviductal modifications of the viviparous species. This project aims the integrative study of the morphology (histology, histochemistry and ultra structure) of S. annulatus females with and without parental care, as well as the alterations in the biochemical profile of the cutaneous secretions. The same will be performed in relation to the oviducts of Chthonerpeton indistinctum. We also intend to study the behavior associated to S. annulatus parental care, including the possible chemical communication through pheromones, among female and the young. (AU)