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Aebi, Alexandre

Nom
Aebi, Alexandre
Affiliation principale
Site web
Fonction
MER
Email
alexandre.aebi@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/769
_
0000-0003-2309-1497

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  • Publication
    Accès libre
    Ecological distribution and niche segregation of sibling species: the case of bean beetles, Acanthoscelides obtectus Say and A. obvelatus Bridwell
    (2006)
    Alvarez, Nadir
    ;
    Mercier, Lény
    ;
    Hossaert-McKey, Martine
    ;
    Contreras-Garduño, Jorge
    ;
    Kunstler Georges
    ;
    Aebi, Alexandre 
    ;
    Benrey, Betty 
    1. 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.
    2. Acanthoscelides obtectus and A. obvelatus are two sister species of bean bruchids, which have been confused until the last decade. One important ecological difference between them has emerged, however: 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 larvae can sometimes complete development in the same seed.
    3. The analysis of 27 622 Mexican individuals of the two species in 2001-2002 and 2002-2003 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 habitats, and at different seasons, were constant from one year to the next.
    4. As 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 pre-adapted them for different altitudes and kinds of resources.
    5. 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.
  • Publication
    Accès libre
    Sibling species of bean bruchids: a morphological and phylogenetic study of Acanthoscelides obtectus Say and Acanthoscelides obvelatus Bridwell
    (2005)
    Alvarez, Nadir
    ;
    Hossaert-McKey, Martine
    ;
    Rasplus, J.-Y.
    ;
    McKey, Doyle
    ;
    Mercier, Lény
    ;
    Soldati, L.
    ;
    Aebi, Alexandre 
    ;
    Shani, T.
    ;
    Benrey, Betty 
    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.
  • Publication
    Métadonnées seulement
    Microsatellite markers in a complex of Horismenus sp.(Hymenoptera: Eulophidae), parasitoids of bruchid beetles
    (2004)
    Aebi, Alexandre 
    ;
    Alvarez, Nadir
    ;
    Butcher, R. D. J.
    ;
    Hansson, Christer
    ;
    Risterucci, A. M.
    ;
    Benrey, Betty 
  • Publication
    Métadonnées seulement
  • Publication
    Accès libre
    Isolation and characterization of polymorphic microsatellite loci in Acanthoscelides obvelatus Bridwell (Coleoptera: Bruchidae)
    (2003)
    Alvarez, Nadir
    ;
    Aebi, Alexandre 
    ;
    Risterucci, A.-M.
    ;
    Hossaert-McKey, Martine
    ;
    Benrey, Betty 
    Five microsatellite loci were isolated from the bruchid Acanthoscelides obvelatus Bridwell (Coleoptera: Bruchidae). Each locus was polymorphic, with the number of alleles ranging from two to 15. We found high levels of within-population variation at most loci, with heterozygosity ranging from 0.182 to 0.900. Cross-species amplification of these loci was tested in two other species of the genus Acanthoscelides, A. obtectus Say and A. argillaceus Sharp.