Journal of Zoological Systematics and Evolutionary Research (2005) 43, 29-37

N. Alvarez, M. Hossaert-McKey, J.-Y. Rasplus, D. McKey, L. Mercier, L. Soldati, A. Aebi, T. Shani and B. Benrey (2005)
Sibling species of bean bruchids: a morphological and phylogenetic study of Acanthoscelides obtectus Say and Acanthoscelides obvelatus Bridwell
Journal of Zoological Systematics and Evolutionary Research 43 (1), 29-37
Abstract: Acanthoscelides Schilsky is a large genus of neotropical bruchid beetles, in which most species show host plant specialization. Acanthoscelides obtectus and Acanthoscelides obvelatus are two sibling species specialized on Phaseolus beans, and are therefore considered pests. Up to now, the status of these two taxa has remained unclear, the few studies conducted having failed to elucidate whether these are two differentiated species or a single morphologically variable species. In addition, A. obvelatus has not been taken into account in the great majority of studies of bean bruchids. In this morphological and genetic study, we show that A. obtectus and A. obvelatus are two 'true' non-hybridizing species, which diverged about 22 Mya. Although the two species demonstrate only few morphological differences, we point out some diagnostic characters that enable their identification in the field. We also address a genetic method of differentiation of the two species, based on species-specific microsatellite loci. The strong morphological resemblance of these two species, despite their ancient divergence, may be the result of evolutionary stasis, which could be the consequence of stabilizing selection. Niche differentiation could enable the two species to coexist indefinitely.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Betty Benrey, Alexandre Aebi

Research topic(s) for pests/diseases/weeds:
identification/taxonomy
molecular biology - genes

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Acanthoscelides obtectus	Beans (Phaseolus)	Mexico
	Acanthoscelides obvelatus	Beans (Phaseolus)	Mexico
	Acanthoscelides obtectus	Beans (Phaseolus)	Cameroon
	Acanthoscelides obtectus	Beans (Phaseolus)	Switzerland