Ecological distribution and niche segregation of sibling species: the case of bean beetles, Acanthoscelides obtectus Say and A. obvelatus Bridwell - INRAE - Institut national de recherche pour l’agriculture, l’alimentation et l’environnement Accéder directement au contenu
Article Dans Une Revue Ecological Entomology Année : 2006

Ecological distribution and niche segregation of sibling species: the case of bean beetles, Acanthoscelides obtectus Say and A. obvelatus Bridwell

Résumé

Molecular techniques have greatly added to the number of known sympatric cryptic species in insects. Ecological differences between these newly distinguished species are little explored, but niches often appear to overlap strongly. These cases are good models for exploring new ideas about species coexistence and community structure. Acanthoscelides obtectus and A. obvelatus are two sister species of bean bruchids, which have been confused until the last decade. However, one important ecological difference between them has emerged: A. obtectus is multivoltine and now distributed worldwide, whereas A. obvelatus is univoltine and restricted to Mesoamerica. Where their ranges overlap, the two species share the same host plants and can sometimes emerge in the same seed. The analysis of 27622 Mexican individuals of the two species in 2001 and 2002 indicates that their niches overlap, but are differentiated with respect to altitude and the kind of beans (wild vs. domesticated). The principal patterns in their relative abundance in different kinds of habitats, and at different seasons, were constant from one year to the next. Since sympatry of these species seems to be of recent origin, the observed niche differentiation may not have evolved in response to competition, but could instead be the consequence of physiological differences, evolved independently in each species in allopatry, that preadapted them for different altitudes and kinds of resources. The combination of biological and historical factors thus appears to allow these two sibling species to coexist in sympatry, despite their broadly overlapping ecological niches.

Dates et versions

hal-02587851 , version 1 (15-05-2020)

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N. Alvarez, L. Mercier, Martine Hossaert-Mckey, J. Contreras, Georges Kunstler, et al.. Ecological distribution and niche segregation of sibling species: the case of bean beetles, Acanthoscelides obtectus Say and A. obvelatus Bridwell. Ecological Entomology, 2006, 31, pp.582-590. ⟨10.1111/j.1365-2311.2006.00817.x⟩. ⟨hal-02587851⟩
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