Niche Diversification and Differentiation as Exemplified by the Snail-killing Flies (Sciomyzidae: Diptera)

Abstract New definitions of “niche diversification” and “niche differentiation” are proposed. The former is the opening up of new adaptive zones through major changes in the environment or though internal changes that allow a range of new resources to be exploited. The latter is the lowering of competition (both intra- and interspecific) within existing adaptive zones through partitioning of resources. These definitions are discussed with respect to Hutchinson’s n-dimensional concept of the niche. The snail-killing flies (Sciomyzidae: Diptera), one of the biologically best known and most species rich higher flies in wetlands, are used as exemplars of this concept.