Niche Breadth and Overlap Measures of Sarcosaprophagous Flies Exploiting Human Settlements

摘要

Sarcosaprophagous flies, filth-inhabiting dipterans, were caught in carrion bait trap from 12 study sites covering township, village and uninhabited places having various sanitary conditions for 3 years covering three seasons per year. Data were analyzed for three measures of niche breadth and five measures of niche overlap. The results show that human settlements provide various habitats to these carrion flies that compete each other to utilize food resource and exploit unhygienic condition of human settlements. It is found that measurement of niche breadth and niche overlap against the resource gradient is necessary in assessing the nature of species packing. It is commented that the degree of overlap among the synanthropic species is quite close than those of asynanthropic species, i.e., nature of resource partitioning is different. Among the niche breadth analyses, plotted graph of Levins' B is helpful in visualizing the niche breadth, All the niche overlap measures, presented in this article, show more or less similar trend of overlap and point towards intense interspecific competition. Cluster analysis and Pearson correlation analyses approve the above outcome. This one-dimensional niche study explained that although intrageneric and inter-generic competition among the fly species is intense they exhibit unique species packing due to resource continuum.