Zabrotes sylvestris, a new species from the United States and Mexico related to Z. subfasciatus (Boheman) (Coleoptera: Bruchidae: Amblycerinae).

Abstract

The new species Zabrotes sylvestris is described from the United States and Mexico. Its very close relative Z. subfasciatus (Boheman), the economic Mexican bean weevil, is redescribed. The two species differ in characters of the male and female genitalia, color of pubescence, carinae on their legs, they do not interbreed, and have distinct differences in DNA. The male and female genitalia of both species are figured and host plants of both species listed. The Mexican bean beetle, Zabrotes subfasciatus (Boheman), is the best known species in the bruchid subfamily Amblycerinae because it feeds in several legumes of economic importance, principally lima beans Phaseolus lunatus (Linnaeus) and common beans P. vulgaris (Linnaeus). This seed beetle species originated in the New World (Credland and Dendy 1992b) along with its primary legume seed hosts. Because it feeds on seeds of economically important legumes, it is cosmopolitan in distribution due to commercial activity. The literature is replete with papers on the economics of this species. Recently we found a new species closely related to but distinct from Z. subfasciatus that usually feeds in seeds of non-cultivated Phaseolus vulgaris. We name this species Z. sylvestris and it is described below. Materials and Methods We used an ocular index in the descriptions. Ocular index = LO/DO, where LO= length of the eye and DO= the distance between the eyes in anterior view. The techniques described by Kingsolver (1970) were used to prepare the genitalia for study and genitalia vials were used to store the genitalia. We also used the nomenclature of Kingsolver (1970) but we modified it so that the description of the sclerites of the internal sac of the male genitalia are made when the internal sac is in repose. Most of the taxonomic publications of Johnson and of Kingsolver contain descriptions of the male genitalia when the internal sac is exerted. For example, our descriptions differ from Kingsolver's