EFFECT OF PREY DENSITY ON BEHAVIOR AND DEVELOPMENT OF THE PREDATORY MOSQUITO, TOXORHYNCHITES TOWADENSIS

The effect of prey density on feeding behaviour, killing behaviour, an d development of the predatory mosquito, Toxorhynchites towadensis, wa s investigated in the laboratory. The number of prey consumed per larv a increased toward an upper asymptote as prey density increased. Prey consumption curves during fourth instar were concave at low prey densi ties but convex at high prey densities. This phenomenon was not observ ed during other instars. Killing without consuming any part of prey oc curred at prey densities of 20 per container and over. The number of p rey killed but not consumed increased linearly with the number of unco nsumed prey in the container. Prey acquisition behaviour was not affec ted by prey densities during the prepupal period. Developmental time f rom first instar to adult emergence decreased with increasing prey den sities, but remained constant at densities of 10 per container and ove r. Adult size increased with increasing prey densities but there was n o effect at prey densities of 20 and over.