446 Final formatted article © Institute of Entomology, Biology Centre, Czech Academy of Sciences, České Budějovice. An Open Access article distributed under the Creative Commons (CC-BY) license (http://creativecommons.org/licenses/by/4.0/). EUROPEAN JOURNAL OF ENTOMOLOGY EUROPEAN JOURNAL OF ENTOMOLOGY ISSN (online): 1802-8829 http://www.eje.cz state of the field cricket population seems to be visible in Germany and Poland. Grein (2000, 2005 after Hochkirch et al., 2007) states that only ten populations are left in Lower Saxony and one west of the Weser River. At the same lati- tude, but 400 km to the east in Poland, the species is still very common and widely distributed throughout the whole country (Bazyluk & Liana, 1990, 2000). This contrast between populations in the west and east of Europe may be the result of differences in land-use man- Genetic identification of a non-native species introgression into wild population of the field cricket Gryllus campestris (Orthoptera: Gryllidae) in Central Europe HANNA PANAGIOTOPOULOU 1, 2, *, MATEUSZ BACA 3, *, KATARZYNA BACA 4 , PAWEŁ SIENKIEWICZ 5 , PIOTR ŚLIPIŃSKI 1 and MICHAŁ ŻMIHORSKI 6, 7, ** 1 Museum and Institute of Zoology, Polish Academy of Sciences, Wilcza 64, 00-679 Warsaw, Poland; e-mails: hpana@miiz.waw.pl, piotrs@miiz.waw.pl 2 Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland 3 Center for Precolumbian Studies, University of Warsaw, Krakowskie Przedmieście 26/28, 00-927 Warsaw, Poland; e-mail: bacamat@gmail.com 4 Institute of Genetics and Biotechnology, Department of Biology, University of Warsaw, Pawińskiego 5a, 02-106 Warsaw, Poland; e-mail: katarzyna.ewa.pajak@gmail.com 5 Department of Entomology and Environmental Protection, Poznań University of Life Sciences, Dąbrowskiego 159, 60-594 Poznań, Poland; e-mail: ophonus@gmail.com 6 Institute of Nature Conservation, Polish Academy of Sciences, Mickiewicza 33, 31-120 Kraków, Poland 7 Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, SE 750 07 Uppsala, Sweden Key words. Orthoptera, Gryllidae, Gryllus campestris, Gryllus bimaculatus, conservation, mtDNA, microsatellite loci, X-chromosome-linked markers Abstract. Two species of the genus Gryllus occur in Europe: G. campestris and G. bimaculatus. The first is widely distributed in the north-western Palaearctic, while the second, G. bimaculatus, occurs predominantly in the Mediterranean area. There is a visible pattern in the distribution of G. campestris, the insect being rare and threatened in the western part of its range, whereas it is still abundant in the east. Despite the fact that this species is commonly used in laboratory experiments, its natural popula- tions are poorly characterised. In the present study, we analysed cricket populations from the lower Oder and Vistula River valleys in Poland. Based on the phylogeny of the mtDNA cytochrome b fragment, we found that 17% of the individuals studied had a G. bimaculatus-like mtDNA haplotype. Analyses of 11 autosomal microsatellite loci failed to reveal any clear genetic differentia- tion between individuals assigned to these two clades. This suggests, along with the spatial distribution of G. bimaculatus-like haplotypes, successful interbreeding of G. bimaculatus with native populations of G. campestris. However, both the nuclear data and additional analyses of two X-chromosome-linked microsatellite loci revealed incomplete introgression. Human-mediated in- trogression seems to be the most plausible explanation of the observed genotypic pattern such that caution needs to be taken in conservation efforts carried out in the western part of the species’ range. * These authors equally contributed to the work. ** Corresponding author; e-mail: michal.zmihorski@gmail.com INTRODUCTION Populations of the field cricket, Gryllus campestris L. (Orthoptera: Gryllidae) vary in terms of conservation sta- tus across the species’ European range. In the UK, Germa- ny, Netherlands, Denmark and Switzerland, the species is rare and included in the Red Lists (Hochkirch et al., 2007). In contrast, populations from central-eastern Europe are abundant, and appear to show stable dynamics over time (Bazyluk & Liana, 2000). The most distinct contrast in the Eur. J. Entomol. 113: 446–455, 2016 doi: 10.14411/eje.2016.058 ORIGINAL ARTICLE