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Accueil du site → Doctorat → Australie → 2006 → Molecular ecology of Dawson’s burrowing bee Amegilla dawsoni (Hymenoptera : Anthophorini)

University of Western Australia (2006)

Molecular ecology of Dawson’s burrowing bee Amegilla dawsoni (Hymenoptera : Anthophorini)

Beveridge, Maxine

Titre : Molecular ecology of Dawson’s burrowing bee Amegilla dawsoni (Hymenoptera : Anthophorini)

Auteur : Beveridge, Maxine

Grade : Doctor of Philosophy PhD (2006)

Université de soutenance : University of Western Australia. School of Animal Biology

Résumé
(Truncated abstract])In the last two decades, the use of microsatellites has revolutionized the study of ecology and evolution. Microsatellites, or short tandem repeats (STRs), are stretches of DNA repeats, 1 to 5 nucleotides long, where the number of repeats varies between individuals. They are co-dominant, highly variable, neutral markers, and are inherited in a Mendelian fashion. Microsatellite loci were isolated from Dawson&​rsquo ;s burrowing bee, Amegilla dawsoni, a large, fast-flying solitary nesting bee endemic to the arid zone of Western Australia. Twelve polymorphic loci were found with an observed number of alleles ranging from two to 24 and observed heterozygosities between 0.17 and 0.85. These loci were used to examine two aspects of this bee&​rsquo ;s molecular ecology ; its population structure and mating system ... The molecular data were also used to show that the nesting female is the mother of all her offspring and that brood parasitism is unlikely in this species. The data indicate that females make daughters at the beginning of the season followed by large sons in the middle, and then small sons at the end. Females often place one brood cell directly above another. The distribution of sex and morph in these doublets follows a pattern with most containing a female on the bottom and a minor male on the top, followed by almost equal numbers of female on top of female and minor male on top of major male. This pattern is likely favoured by emergence patterns, with males emerging before females and minor males emerging before major males. I suggest that although minor males have low reproductive success, their production may nonetheless be beneficial in that minor males open up emergence tunnels for their larger and reproductively more valuable siblings. In addition, minor males may represent the &​lsquo ;best of a bad job&​rsquo ; provisioning tactic arising from changes in the costs to nesting females of gathering brood provisions over the course of the flight season. This thesis demonstrates that microsatellites can be used to answer many questions regarding the molecular ecology of a species from the behaviour of the bees on a population scale to the mating behaviour of individual bees and how they allocate resources for the next generation. Many other aspects of the bee&​rsquo ;s ecology could also be examined now that suitable molecular markers exist.

Présentation (National Library of Australia)

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