PROTEIN HYDROLYSATES AND ASSOCIATED BACTERIAL CONTAMINANTS AS OVIPOSITION ATTRACTANTS FOR THE MOSQUITO CULEX-QUINQUEFASCIATUS

Six protein or protein hydrolysate solutions were tested for activity as attractants for ovipositing Culex quinquefasciatus mosquitoes in the laboratory. Four of these solutions (egg albumin, lactalbumin hydrolysate, casein hydrolysate and yeast hydrolysate) were attractive to ovipositing females at varying concentrations, when compared to distilled water controls. Soy hydrolysate was repellent at 1%, but not significantly attractive or repellent at lower concentrations. 'Nulure', a tephritid fly bait containing protein hydrolysate, also had no significant effect on oviposition behaviour. Gravid females mostly oviposited within the first 4 h of the scotophase, regardless of the presence or absence of an oviposition attractant. Lactalbumin hydrolysate 1% solution, with or without 0.1% neomycin antibiotic, was attractive to Cx quinquefasciatus. This effect was reduced by the presence of neomycin which, alone, had no effect on oviposition. Hence both lactalbumin hydrolysate and bacterial contaminants were shown to be attractive to gravid Cx quinquefasciatus.