Genetic patterns reveal an old introduction event and dispersal limitations despite rapid distribution expansion

• Identifying sources of range expansions after an introduction event and understanding the species dispersal are essential for effective management of invasive species. In a unique study system we investigated the spread and distribution of genetic diversity subsequent to a known colonization event and in the light of the well-known biology of the rapidly expanding Roesel's bush-cricket (Metrioptera roeselii), a species that is non-native in Sweden. Using eight microsatellite markers we analyzed genetic variation in 837 individuals collected at 29 sites across the species total range in central Sweden to verify the species local origin and to determine how the species known dispersal biology affect the population genetic structure throughout its range. We found that unique allelic richness was highest in a site approximately 16 km southwest of the previously suggested site of establishment, pointing towards a site of introduction close to a royal stud farm from where it is known that animals have been imported from Europe. Despite the species rapid expansion, genetic diversity in the core of the distribution was higher than in the populations at the range margin. Bayesian cluster analyses also revealed that genetic structuring was more pronounced in the range margin, indicating the occurrence of dichotomous dispersal behaviour of the species with occasions of rare long distance events. Our study shows that good sampling design and appropriate choice of genetic markers can help to identify species local origin and explain genetic patterns that arise during range expansions.

Ämnesord

NATURVETENSKAP  -- Biologi -- Genetik (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Genetics (hsv//eng)

NATURVETENSKAP  -- Biologi -- Ekologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Ecology (hsv//eng)

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