Effects of Cannibalism and Intraguild Predation on Pondskaters (Gerridae)

Gerrid-gerrid predation can limit gerrid numbers and affect phenological patterns. In a field experiment with G. pingreensis, survival of small gerrids was dramatically reduced in the presence of larger juvenile instars, and survival of larger nymphs to the adult stage was significantly greater when given access to younger stages than when held by themselves. Mass of teneral female cannibals was significantly greater than that of females not given access to younger stages, but there was no effect on male mass or on development time of either sex. Predation by G. pingreensis on G. buenoi was not consistently more common than cannibalism in either laboratory or field experiments