Variability and distribution of the golden-headed weevil Compsus auricephalus (Say) (Curculionidae: Entiminae: Eustylini)

Abstract

The golden-headed weevil Compsus auricephalus is a native and fairly widespread species across the southern U.S.A. extending through Central America south to Panama. There are two recognised morphotypes of the species: the typical green form, with pink to cupreous head and part of the legs and the uniformly white to pale brown form. There are other Central and South American species of Compsus and related genera of similar appearance that make it challenging to provide accurate identifications of introduced species at ports of entry. Here, we re-describe the species, provide images of the habitus, miscellaneous morphological structures and male and female genitalia. We discuss the morphological variation of Compsus auricephalus across its distributional range, by revising and updating its distributional range, based on data from entomological collections in the U.S.A. and Canada. The revised distribution of C. auricephalus extends as far south as Zacapa in Guatemala. Records south from there correspond to a different species, with affinities to C. auricephalus that we discuss and illustrate. We also discuss morphological affinities and differences with other similar species. Furthermore, we summarise information regarding the biology, host plants and natural enemies of C. auricephalus.