New incipient species under reinforcement in the Drusus discolor new species complex (Limnephilidae, Trichoptera)

In a comprehensive survey high genetic differentiation with haplotype endemism was detected between mountain range populations of the montane caddisfly species Drusus discolor especially in the Pyrenees, Massif Central, and Western Alps. However no morphological divergences were recognised by traditional morphology. In the present study, covering the entire area of the species we have discovered stable paraproctal divergences in the same mountain ranges by applying the speciation trait approach together with fine structure analysis and demonstrated empirically by diverged trait matrices. Unlike other limnephilid taxa the parameres in Drusus genus vary stochastically with mutation, genetic drift, and recombination as well as modified by standing genetic variation and by fluctuating asymmetry of developmental instability and environmental plasticity. Morphological divergences of the speciation trait evolved from the ancestral species in peripatry during sexual selection processes. We theoretized the possibility that the reproductive barriers were reinforced or are under reinforcement in secondary contacts. Subtle and stable divergences resulted in the formation of phylogenetic incipient sibling species: Drusus ferdes sp. n., D. kupos sp. n., D. leker sp. n. D. visas sp. n