NICHE RELATIONSHIPS IN SHORE BUGS OF THE GENUS Valleriola

Abstract

Valleriola buenoi (Usinger) and Valleriola mindorana Drake were found to "coexist" on the same rock surfaces in the same area at the same time in Molawin Creek, Los Baños, Laguna. A closer examination of their niche relationships revealed varying degrees of habitat specialization in favorable areas. Differences in dispersion, behavioral patterns and microclimatic factors influencing fluctuation in their populations reveal a well-defined degree of niche divergence which explains their coexistence. Elevation, rock size and vegetation cover strongly determine their presence in streams. Observed mating preference for members of the same species demonstrates distinctness of V. buenoi and V. mindorana.