Genetic signature of the colonisation dynamics along a coastal expansion front in the damselfly Coenagrion scitulum |
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| Authors: | JANNE SWAEGERS JOACHIM MERGEAY AUDREY ST‐MARTIN GEERT DE KNIJF MAARTEN H D LARMUSEAU ROBBY STOKS |
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| Affiliation: | 1. Laboratory of Aquatic Ecology, Evolution and Conservation, University of Leuven, Leuven, Belgium;2. Research Institute for Nature and Forest, Geraardsbergen, Belgium;3. Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden;4. Research Institute for Nature and Forest, Brussels, Belgium;5. Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Leuven, Belgium;6. Laboratory of Forensic Genetics and Molecular Archaeology, University of Leuven, Leuven, Belgium |
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| Abstract: | 1. Many insects are expanding their distribution range polewards as a result of climate change, which has been shown to be associated with founder effects leading to a reduction in genetic diversity and an increase in genetic differentiation. These spatial genetic patterns may arise from colonisation from a broad expansion front or a limited neighbourhood after a stepping stone model of dispersal. The temporal persistence of such founder effects are poorly understood, mainly because studies looking at the fine‐scale initial temporal dynamics of the genetic signature of a range expansion are rare. 2. Using microsatellite markers, we performed a detailed spatiotemporal genetic analysis of the range expanding damselfly Coenagrion scitulum (Rambur) along a coastal axis during the first years after colonisation. 3. A decrease was in (private) allelic richness when going northwards along the coastline, which is consistent with a scenario of cumulative founder events. In spite of the spatiotemporal dynamics in the observation records of the species along the coastline, the spatial genetic data indicated a major contribution from the broad expansion front during the colonisation of the coastline rather than a stepping‐stone colonisation process. 4. The fine‐scale temporal dynamics of the range expansion indicated the absence of persistent founder effects and instead showed considerable temporal instability in genetic indices at the more northern edge populations. This may be explained by genetic immigration and admixture from the broad expansion front in this active disperser. |
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| Keywords: | Coenagrion scitulum founder effect genetic diversity isolation‐by‐colonisation range expansion |
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