Polytene chromosomes of an Indian Himalayan black fly Simulium (Nevermannia) praelargum (Diptera:Simuliidae)

摘要

High quality polytene chromosome maps (n=3) of a Himalayan Simuliid Simulium praelargum Datta, 1973 are presentedand represent the first cytological description of a taxon found in the feuerborni group, subgenus Nevermannia. Polytenechromosomes one (Ⅰ) and two (Ⅱ) are metacentric, chromosome three (Ⅲ) is submetacentric with the length of each chromosomeoccupying 37.25 %, 31.36 % and 31.34 % of the total complement length, respectively. Typical simuliid diagnostic intergenericchromosomal markers are found within the polytene complement of this species. The nucleolar organizer (N.O.) is found at thebase of the short arm of chromosome one (IS), the Ring of Balbiani (R.B.), double bubble (D.B.) and triad occur in the short armof chromosome two (IIS), the Parabalbiani Ring (P.B.) and grey band (gb) occur in the long arm of chromosome two (IIL) and theBlister (BL) and Capsule (Ca) occur in the short arm of chromosome three (HIS).Terminal bands at the end of HIS are heterochromatinizedand present atypically with respect to other simuliid fauna. Populations studied so far are unique among the Simuliidaein that they exhibit chromosome structural monomorphism. These high resolution polytene chromosome maps will form thebasis for future cytological characterization and phylogenetic comparisons amongst members of the feuerborni group.