EVALUATION OF MESOCYCLOPS-ASPERICORNIS (CYCLOPOIDA, CYCLOPIDAE) AND TOXORHYNCHITES-SPECIOSUS AS INTEGRATED PREDATORS OF MOSQUITOS IN TIRE HABITATS IN QUEENSLAND

This study addressed biological control of peridomestic Aedes notoscri ptus, known to be a highly effective colonizer of tire habitats and a possible vector of Ross River virus. A laboratory trial of the compati bility of the predators Mesocyclops aspericornis and Toxorhynchites sp eciosus in small container habitats showed that 4th-instar Tx. specios us did not significantly affect M. aspericornis mortality. Introduced M. aspericornis and naturally occuring Tx. speciosus were found to for m a compatible predator pair for reduction of larval Ae. notoscriptus and Culex quinquefasciatus populations in tire habitats. Over 22 month s of field survey, 97% of tires without predators contained mosquito l arvae, at a median density of 43 larvae/liter. By comparison, 51% of t ires containing both predator species held mosquito larvae at a median density of 4 larvae/liter. Predation by Tx. speciosus persisted for t he duration of the study. The inability of the Lake Kurwongbah strain of M. aspericornis to tolerate temperatures of less than or equal to 1 0 degrees C, which are prevalent in Brisbane during winter, resulted i n a failure to deliver persistent reduction of mosquitoes in tires. Th e temperature-dependent population characteristics of M. aspericornis emphasize the long-recognized importance of matching a biological cont rol candidate's physiological requirements to the environment in which control is sought.