Original paper

Population genetic structure of the caddisfly Rhyacophila pubescens, Pictet 1834, north of the Alps

Engelhardt, Christine H.M. Pauls; Haase, Peter


In this study we analyse the genetic population structure of the caddisfly Rhyacophila pubescens, a montane aquatic insect with a Central European distribution range. The species exhibits an insular distribution pattern due to its strong binding to unimpaired tufa streams and thus to mountain ranges with calcareous geology. We examined sequence data (mtCOI) of 197 individuals from 33 sites of the northern part of the distribution range to elucidate whether genetic population structure reflects this insular distribution. 28 haplotypes were identified, one of which was central in the median-joining haplotype network, occurred all across the study area, and seemed to be ancestral to others. In almost every mountain we also found closely related, private haplotypes indicating recent differentiation processes. Exact tests of population differentiation and pairwise FST values showed that most mountain ranges that were studied are significantly differentiated from one another, indicating limited gene flow between mountain ranges. Analysis of Molecular Variance (AMOVA) revealed that most variation was within (68.54 %) and among mountains (30.48 %, for both p < 0.0001), but not among major mountain ranges (0.98 %, p = 0.31). analysis of demographic history inferred recent demographic expansion in every region of the study area and the entire data set. together these results provide evidence that limited extant gene flow and isolation between populations are currently structuring the populations north of the alps. we present different hypotheses how the present-day genetic pattern of R. pubescens could have developed from its contrasting pattern in the past.


trichopterarhyacophila pubescensmtcoipopulation genetic structurefragmentationtufa streams