Human-facilitated metapopulation dynamics in an emerging pest species, Cimex lectularius.
Bottom Line: Founder events often result in drastic reductions in diversity and an increased influence of genetic drift.ABC results suggest a common origin of all founders of a given subpopulation and that the numbers of colonists were low, implying that even a single mated female is enough to found a new infestation successfully.These patterns of colonization are close to the predictions of the propagule pool model, where all founders originate from the same parental infestation.
Affiliation: Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK; Department of Biosciences, University of Helsinki, PO Box 65 (Viikinkaari 1), FI-00014, Helsinki, Finland.Show MeSH
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Mentions: The two scenarios used in our ABC analysis are illustrated in Fig. 1. For both, we simulated 20 microsatellites from 13 infestations using the same sample size per infestation as obtained from the field (Table3). Note that from our 21 original microsatellites, the locus Cle001 was omitted, due to a large range of allele sizes that reduced our ability to fit the models. For the migrant pool model, we approximated the multiple origins of new infestations by randomly drawing individuals from a large panmictic population serving as a proxy for the metapopulation (scenario one). The propagule pool model was designed such that colonists founding a particular infestation all came from the same source infestation, itself derived from the large panmictic population (scenario two; Fig. 1). In both cases, we would expect a severe bottleneck at the point of founding, followed by a period of rapid growth. Because infestations are believed to be invariably settled through strong bottlenecks and to have short lifespans, we do not expect them to differ widely in age at sampling time or in effective population size. We thus simplified the models by constraining Ne, t2 and t3 to be shared by all infestations.
Affiliation: Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK; Department of Biosciences, University of Helsinki, PO Box 65 (Viikinkaari 1), FI-00014, Helsinki, Finland.