Vol. 110 - Part III - Zoological Survey of India

MITRA & MEHTA : A preliminary note on the conservation of Saproxylic flies.............in Himachal Pradesh 3The Scatopsidae are a species-poor, cosmopolitanfamily of small dark nematocerans (0.6 mm to nearlyy 5mm) usually black, and wings with distinctly darkenedand thickened anteior radial veins contrasting with palerposterior veins. Of the 3 species of India only a speciesEctaetia nigronitida (Brunetti) is present in theHimachal Pradesh.Therevids (Stiletto flies) are more or less elongatedensely pubescent flies with slender non-prehensilelegs. They are brightly coloured, elongate, with largelyglabrous bodies. The antennae are sometimes verydistinctive. They are found in a variety of habitatsranging from rainforest to desert. The snake-like larvaeare very mobile and move with considerable speedthrough sand and loose soil. Larvae inhabit the soil inleaf-mould, fungi, decaying wood etc. The Therevidaeare represented by 16 species in India of them onlyThereva bilineata Brunetti known from HimachalPradesh.The Robber flies, or Asilidae, comprise one of thelargest and most abundant families of Diptera. Adultstages are medium to large flies often observed on stemsof plants, on the ground and grass or flying low. Speciesvary in apperance and some mimic wasps and bees.Most species are gray to black, hairy-bodied, have along, narrow, tapering abdomen containing segmentsthat may be banded, patterned or contrasting in color.The larva of Robber-flies is believed to be mostlyherbivorous (vegetarian) but the adult flies are highlyactive carnivores. Of the 482 species reported from India6 species are known from Himachal Pradesh.The family “Empididae” in the traditional sense is adiverse group of medium to small sized (1 to 15 mm),grey, yellowish or dark very rarely metallic colouredflies. The head is variously shaped and usually narrowerthan thorax. The wings are of varied shape and size.They are commonly called as “dance-flies” and gaintheir common name from their courtship behaviour.Empidoids breed in a variety of habitats, includingrunning water, tidal zones, decaying wood, and moistsoil. Adults are often found in various forest habitats,on leaves, tree trunks, aquatic vegetation, or in streambeds and seepage habitats. Larvae are soil inhabitants,but also sometimes found in decaying wood, humus,dungs, moss or in water. The family includes 57 speciesin India with only 13 species being reported fromHimachal Pradesh.Flower Flies or hover flies belong to the familySyrphidae are abundant everywhere except in arid areasof the Old World and in the extreme southern latitudes.Their size ranges from 4 mm to over 25 mm and theircoloration from bright coloration from bright yellow ororange to dull dark black or gray with a few iridescentforms. Larvae of the subfamily Syrphinae arepredaceous on soft-bodied arthropods, although somemay occasionally be scavengers. Most of the milesiinesare saprophagous and found in litter and dead wood,some of the rhingiines are mycetophagous, and a fewrhingiines and merodontines are phytophagous (asborers in tubers, stems, and wood, miners in leaves).46 species of hoverflies are reported from HimachalPradesh whereas 256 species known from India.DISCUSSIONInvariably, insects are overlooked when forestmanagement issues are discussed, because there areso many species, which are taxonomically intractableand so poorly known. Often people take the view thatif you look after the vegetation and vertebrates, theinsects will look after themselves. This may be true forsome functional groups, but for saproxylic insects, thisseems unlikely. Their study deserves high priority, sincethey are dependent on the very resource “wood” whoseremoval from the ecosystem is the usual object of forestmanagement (Grove S.J. and Stork N.E. 1999).The ecological value of dead wood is broadlyacknowledged worldwide. Recent research hashighlighted their sensitivity to forest management, withmanaged or secondary forests generally supportingfewer individuals, fewer species, and differentassemblages compared to old-growth or primary forests.this sensitivity is a product of their association with ahabitat that tends to diminish in managed forests. Manysaproxylic insect species have declining populationsand are regarded as threatened due to low habitatavailability in managed forests.The geographical area of Himachal Pradesh is 56,673km2. According to the State Forest Report, 1997 of FSI,the actual forest area in the state occupies only 22.5%of its area. Of them non-Forest : 74.2%, Very Dense