ADHEARING RESPONSE AMONG GASTROPOD SNAILS IN DESERT REGION OF RAJASTHAN (NORTH INDIA)

Adhearing preference among these gastropod snails namely Bellamya bengalensis, Gabbia orcula and Digoniostoma pulchella were studied in fresh water ponds namely Gajner pond and Kodemdesar pond near Bikaner, Rajasthan (Indian Desert) as well as under laboratory conditions.The study was carried out for an annual cycle encompassing all the three seasons summer, monsoon and winter (May,2009 to April 2010). Prosobranch snails collected by sieving method (vide 3.2.2) was studied under stereoscopic binocular microscope and bull lens. The forms were identified and counted. Identifications were made following Subba Rao (1989). In the field, observations were made with respect to the substrate preffered by individual species in water. B. bengalensis basically inhabitat 90% on pond mud, G.orcula were found to float (60%) close to surface and D. pulchella showed 67% free floating. In laboratory 20 healthy specimen of each recorded species were released in aquarium containg pond water and mud. Vegetation Hydrilla and wood pieces (dried twigs) were also placed in aquarium. Bellamya bengalensis did not harbour on artificial subsratates. G. orcula and D. pulchella found mostly free floating in aquarium and some found attached to the glass wall of aquarium.