DIFFERENTIAL RESPONSES OF AEDES AND CULEX MOSQUITOS TO OCTENOL OR LIGHT IN COMBINATION WITH CARBON-DIOXIDE IN QUEENSLAND, AUSTRALIA

Field studies were conducted with EVS (encephalitis vector surveillanc e) traps in south-eastern Queensland, Australia, to determine the rela tive response rates of mosquitoes to three levels (0.1, 4.5 and 30 mg/ h) of 1-octen-3-ol (octenol) in combination with a standard bait of 22 00g carbon dioxide (CO2), compared with CO2 alone or CO2 with light fr om a 6V incandescent bulb. Compared to CO2 alone, Aedes vigilax collec tions increased significantly when CO2 was supplemented by all three o ctenol emission levels, but not by the addition of light. Furthermore, the 4.5 and 30 mg/h release rate of octenol gave a significant increa se in numbers of Ae. vigilax relative to that from CO2 + light. In con trast, collections of Culex annulirostris and Culex sitiens were not e nhanced significantly by either the addition of light or octenol at al l three levels. Fewer Cx sitiens were collected with octenol released at 4.5 mg/h in comparison to CO2 alone. These differential sampling ra tes should be taken into account when using EVS traps.