Polimorfismo de la estructura mandibular en especies sudamericanas de Heterocerus Fabricius (Coleoptera: Heteroceridae: Heterocerini)

Abstract

The overgrowth of the mandible in male specimens is described. These overgrown madibles present strong modifications: elongation of the mandibular body, shift in position of the prostheca due to an increased curvature of the mandible, and apparition of a dorsal process (mandibular horn) on the dental lobe. These features are measured, and several stages of each character are arbitrarily defined. Only a small percentage of the studied males present overgrown mandibles. Studied species are: H. similis Grouvelle, H. bruchi Grouvelle, H. woodruffi (Pacheco), and H. rivularis (Germain). Heterocerus meridianus (Pacheco), which is mentioned in the literature and presents the same characteristics, is also discussed.