Sexual dimorphism and morphological variation in populations of Ceroglossus chilensis (Eschscholtz, 1829) (Coleoptera, Carabidae)

Abstract

We evaluated differences related to body shape of males and females of Ceroglossus chilensis using morphometric geometry.  This species is widely distributed in Chile, associated with native forests and exotic plantations.  In December 2004 and January 2005 we collected 53 males and 63 females from two plantations of Pinus radiata located in the Coast Range and Andes foothills in the RegiÓn del Bío-Bío.  Individuals were photographed, and 17 landmarks from lateral and ventral views were digitized. We used a multivariate analysis of variance with sex and locality as factors to investigate differences in body form among sexes.  Sexual dimorphism was present in both populations; males had a wider proepisternum, while females had a narrower proepisternum and wider abdominal sternites.  Differences among populations were also found; the abdomen of both males and females from the Coast Range is more elongated and thicker than in the Andes foothills.  These differences raise the question of whether sexual dimorphism may be modulated by natural selection.