Structure of the genetic variation in the common springtail Isotomiellaminor (Hexapoda, Collembola) from contrasting habitats: evidence for different genetic lineages at a regional scale?

Abstract

Although Isotomiellaminor (Schäffer, 1896) (Collembola) is widely distributed in temperate regions, it is one of the less-studied species genetically. The genetic variability and its structure in the common springtail I.minor were investigated on a regional geographic scale using mitochondrial (COI) and nuclear (28S rDNA) markers. A total of nine populations from urban habitats of the Košice city agglomeration and four populations from natural sites of the karst landscape were used for the present study carried out in the Western Carpathians, Slovakia. Up to nine cryptic lineages (MOTUs - molecular operational taxonomic units) were independently recognised by two molecular delimitation methods. In addition, high genetic distances between lineages were observed (p-dist: 10.87-22.75% and K2p: 11.98-27.22%), comparable to the genetic distances between species. This study showed that urban and natural habitats harbour significantly different genetic lineages. Limited dispersal of MOTUs (lineages) between natural and urban populations was also supported by analysis of molecular variance (AMOVA). While the I.minor populations at urban sites were mixtures of different lineages, the populations at natural sites were monophyletic and their haplotypes/genetic lineages were clearly grouped by individual sites. Possible ecological filtering between urban and natural environments within MOTUs is discussed with respect to the evolution of parthenogenetic species I.minor in this habitat complex.