INVENTORY OF THE TRUE FLIES ( DIPTERA ) OF THE THAR DESERT

Great Indian Desert or the Thar Desert with its xeric environment is known to harbour an improvised fauna. The members of the order Diptera are commonly known as flies, gnats, midges, mosquitoes, keds, bots, etc. This diversity of names documents the importance of the group to man and reflects the range of organisms in the order. However, it is admittedly true that there is a paucity of knowledge on the account that does not show the Diptera of distinction that are absolutely prone to the arid and semi-arid situations in the desert.


INTRODUCTION
Great Indian Desert or the Thar Desert with its xeric environment is known to harbour an improvised fauna.The members of the order Diptera are commonly known as flies, gnats, midges, mosquitoes, keds, bots, etc.This diversity of names documents the importance of the group to man and reflects the range of organisms in the order.However, it is admittedly true that there is a paucity of knowledge on the account that does not show the Diptera of distinction that are absolutely prone to the arid and semi-arid situations in the desert.
A perusal of literature revealed that Kumar and Kumar (1996) have provided first exhaustive list of dipterans of the Thar Desert enumerating 84 species belonging to 45 genera spread over 22 families.However, recent studies on this group from Thar Desert by Parui and Mitra (2000), Banerjee and Mitra (2002) and Mitra et al., (2002) have further substantially increased our knowledge bringing the tally of the species to 155 belonging to 77 genera spread over 27 families.
The systematic list is as follows :   The subterranean water is certainly insufficient to support any but very scanty plant life.However, there is abundant growth of annual vegetation shortly after the commencement of the rainy season but the greenery withers with the withdrawal of the monsoon.All these adverse conditions impose restrictions also on the animal lives that not only interact among themselves but also with various plants, plant predators and plant parasites.Therefore, the desert does not exhibit a flourished fauna that normally occurs in other ecosystems.
The Great Indian Desert or Thar Desert covers part of the four Indian states (Punjab, Haryana, Rajasthan and Gujarat) and two provinces of Pakistan (Sind and Punjab).There are 28 districts of the 4 states coming under the Thar Desert of which major area lying in the states of Rajasthan (13 districts) and Gujarat (8 districts).Besides this, 4 districts of Haryana and 3 districts of Punjab are also fall under the Thar desert of Indian part.
The dipterans in their adult stage are generally terrestrial but some need to go to water for oviposition or so.Indeed, they are in their 1arval stages more moisture loving and the great majority live in water, in rotting vegetable or anilnal matter, inside living plant tissues or bodies of other animals or in substrata where necessary moisture for vital process exists.It is true that the scarcity of water in the desert prevents most aquatic Diptera from colonization and the semi-aquatic Diptera that live in soil or in plants and animals have to live either in or decaying matters thus cannot undergo complete development.In fact, the other cause of limitation to many such Diptera in the desert is the physiological draught mostly due to the salinity of soil and water they inhabit.
The arid and semi-arid situations of the desert are likely to support high size population of the Asilidae, the Bombyliidae, the Conopidae and the Nemestrinidae in their diversity but the recorded fauna does not depict the true picture except the Asilidae (21 species) and the Bombyliidae (10 species).