Vol. 4, Issue 2 (2019)
Impact of Geographical elevations on the eco-distributional pattern of Drosophila (Diptera) species in four different ecosystems of Karnataka, India
Author(s): Alwyn D’Souza, Manjunath Mahalingappa, Shakunthala Venkat
Abstract: Analyzing the changes in eco system co-related with species diversity across different altitudinal and latitudinal gradients are essential in understanding the complex nature of biodiversity. Four different eco systems was selected and analyzed to examine the altitudinal and latitudinal variations in the distributional pattern of Drosophila (Diptera: Drosophiladae) Population in Kodachadri Hills, Kath lekhan, Gopal Swamy Hills and Nandi Hill regions of Karnataka state, India. Cluster analysis, constancy methods, Simpson’s, Berger-Parker’s, and Shannon-Weiner indices were used to analyze the species occurrence qualitatively. We hypothesized that the Gause’s competitive exclusion principle still remains to be questionable and have used 4 sets of environmental data to build a model using Venn’s 4 set diagram illustrating the common species accommodated at differing eco systems and have characterized species- environment relationship. We recorded 13 species from 8 different altitudes varying between 530m and 1478m and evaluated clinal trends in species distributional pattern among different ecological niche. The result indicates that Drosophila community was significantly affected by elevation as the density of Drosophila decreased with increasing altitudes. Drosophila ananssae, Drosophila bipectinata, Drosophila malerkotliana, Drosophila nasuta and Phorticella striata were the 5 common dominant species, further, Drosophila bipectinata and Drosophila malerkotliana being the two competing sympatric species was co-existed in all the four different eco systems. These data indicate there is a positive correlation between species diversity and elevation and also there is an emphatical interaction between competing species to co-exist in the same niche.