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Himalaya; stream; aquatic Empididae; new species; emergence patterns; environmental variables; species richness; Oriental Region
Abstract:
For the first time an emergence trap was permanently run for almost two years over a Himalayan stream (Kullu Valley, SW-Himalayas, Himachal Pradesh, India). The area is situated in monsoon climate. We report the results of the emergence of aquatic dance flies (Empididae: Hemerodromiinae, Trichopezinae and Clinocerinae). Forty-nine taxa were distinguished, and thirty-three were determined to species level; seventeen species were new to science. In Hemerodromiinae five new species of the genus Hemerodromia MEIGEN, 1822, and ten of Chelifera MACQUART, 1823, were found over approx. 5 m² of stream surface. One species of Heleodromia HALIDAY, 1833, subfamily Trichopezinae, was new. In Clinocerinae, two species of Dolichocephala MACQUART, 1823, three of Roederiodes COQUILLETT, 1901, seven of Clinocera MEIGEN, 1803 and one of Trichoclinocera COLLIN, 1941, were new to science. Species and specimen number of Clinocerinae, particularly Wiedemannia glaucescens (BRUNETTI 1917), were highest at high precipitation; Hemerodromiinae were more abundant during the dry periods. Species richness is remarkably high, compared with studies on European or North American streams. Probably many endemics exist. Morphological similarity of several Clinocera species indicates intense speciation processes. Species richness may further depend on the position of the Himalayas between the Palaearctic and the Oriental region, and the vicinity of climatic zones along the different elevations and slopes of the mountain chains. Provisional keys for the genera Chelifera, Hemerodromia, Heleodromia and Clinocera are provided.
