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

Abstract

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.

A clue to invasion success: genetic diversity quickly rebounds after introduction bottlenecks

“…This highly controlled, long-term and detailed study setup gave us a unique opportunity to address questions on genetic processes in this non-native species and investigate mechanisms behind these. In combination with knowledge about the species' colonization history (Kaňuch et al 2013;Preuss et al 2015), dispersal behaviour (Berggren et al 2001(Berggren et al , 2002Hochkirch and Damerau 2009;Eriksson et al 2013;Preuss et al 2014) and adaptations (Kaňuch et al 2014(Kaňuch et al , 2020, this creates opportunities that, to our knowledge, previously have not existed in any other system. The introduction sites have been censused regularly in order to gather information on the species establishment success, population dynamics and local dispersal, and this allowed us to obtain fundamental information about genetic processes and patterns associated with early establishment success.…”

“…Sampled individuals were stored in 96% ethanol at -80°C until analysed and measurements of genetic characteristics were based on microsatellite data. We isolated DNA from the muscle tissue of the hind-femur using the Chelex 100 (Bio-Rad) extraction method (Walsh et al 1991) and amplified nine polymorphic microsatellite markers (MR2-16, 2-42, 3-24, 3-34; Holzhauer and Wolff 2005 and Metroe08, 19, 20, 24, 27;Kaňuch et al 2010) according to adapted PCR protocol described by Preuss et al (2015). All microsatellite loci were tested for the presence of null alleles, effects of stuttering, and large allele dropout using MicroChecker 2.2.3 (van Oosterhout et al 2004).…”

Assessing non-native invasive Orthoptera in Europe

“…Finally, the presence of Orthoptera species can be studied using automatic acoustic monitoring (Lehmann et Nowadays, however, the usage of species-speci c biological pathogens is increasing, making possible outbreaks in the future potentially less frequent (Gerber & Schaffner, 2016; CABI, 2020). Furthermore, knowledge about the origin of a species, the way of introduction and the dispersal pathways and patterns are crucial to understand and develop effective management strategies (Preuss et al 2015). Here, data collection programs would be useful to collate information, thereby detecting and preventing possible introductions that could lead to outbreaks at an early stage (Bauer et al 2022).…”

“…A similar pattern has been documented for S. gregaria and C. italicus (Bauer et al 2022). The presence of non-native Orthoptera species can also lead to changes in the distribution and abundance as well as the persistence of native species, potentially causing shifts in ecosystem composition and functioning (Preuss et al 2015). In addition to the direct impact on agriculture, their spread can also affect human well-being by increasing food prices and reducing the availability of certain food items (Bauer et al 2022).…”

Assessing non-native invasive Orthoptera in Europe

“…The vast majority of European non-native species are terrestrial arthropods , including Orthoptera. Several Orthoptera species, in particular grasshoppers, crickets and bush-crickets, have been introduced to Europe in the past (European Alien Species Information Network, EASIN; Katsanevakis et al 2012;Preuss et al 2015;Ćato & Zagorac, 2021;Krištín et al 2022).…”