Phenotypic and Genetic Diversity of Peregrine Earthworms in Western Himalaya

Abstract

newline xiv newlineABSTRACT newlineSeveral exotic peregrine species of earthworms are found in the Western Himalaya. Their occurrence in the region has been attributed to transportation through various anthropogenic means and activities. Accurate identification of these invasive earthworms to the species level/lineages is crucial for understanding their impact on the soil community structure and function, and for monitoring their range expansion. Inconsistency and instability of morphological characters make it difficult to identify earthworms. DNA barcoding for species identification provides additional data set in alpha taxonomy. In the present studies, an integrative taxonomic approach was, therefore, employed to identify earthworms collected from the state of Himachal Pradesh. newlineMitochondrial gene analysis was undertaken to study genetic diversity in some selected peregrine species and determine their phylogenetic relationships. Cryptic species of exotic Aporrectodea caliginosa species complex (Family Lumbricidae) were identified as A. tuberculata (Eisen, 1874) and A. trapezoides Dugès (1828). The specimens of A. trapezoides belonged to Mediterranean lineage as per mitochondrial COII and 16S gene analyses. Mitochondrial COII gene results indicated that it belonged to clone 1 distributed in Mediterranean and Eurosiberian regions. The original home of A. tuberculata was traced to Poland and Scandinavian countries in Eurosiberian region. newlineThe Western Himalaya have another group of peregrine earthworms of the genus Drawida Family Moniligastridae) represented by D. japonica (Michaelsen, 1892) and D. nepalensis Michaelsen, 1907. Mitochondrial COI and 16S gene analyses showed pigmented Drawida morphospecies sp1 having dorsal pores (cf. D. japonica and koreana) was genetically similar to D. koreana from Matsu Islands and some unpublished sequences of koreana in NCBI, and D. japonica from Shandong and Liaodong peninsulas of China. But was found genetically distinct from D. japonica from Japan and as well as other records of japonica from China in mitochondrial COI analysis. Further studies, including integrative taxonomic approach, are needed to unravel this taxonomic puzzle. D. nepalensis showed close affinity with D. assamensis, indicating its origin in northeast Hills than supposedly in the Himalaya. newlineKeywords: Earthworms, peregrine species, phenotypic diversity, genetic diversity, phylogeny, Lumbricidae and Moniligastridae