Use of a rostral appendage during social interactions in the Ecuadorian Anolis proboscis

The use of sexually selected characters in inter- and intra-sexual interactions has long been of interest to evolutionary biologists. Recently, a distinction between sexually selected traits as ornaments versus weapons has been advanced. We investigated the behaviour of an enigmatic lizard with a prominent sexually dimorphic trait in an effort to describe whether the trait was the product of sexual selection and further whether it functioned as a weapon or an ornament. The subject of our study was the Ecuadorian proboscis anole (Anolis proboscis), a slow-moving cryptic species endemic to the north-western slopes of the Andes in Ecuador. Males, but not females, of this species bear a rostral appendage that has been described as an exaggerated trait resulting from sexual selection. However, a thorough description of the use of the rostral appendage in social interactions is lacking. Here, we describe social interactions of this species during 11 male–female courtships and mating interacti...