FACTORS AFFECTING NUMBERS OF CULICOIDES IN TRUCK TRAPS IN COASTAL QUEENSLAND

Truck trap collections of Ceratopogonidae were made over a period of 2 7 months (November 1973-February 1976) at Tingalpa Creek, in southeast Queensland, Australia. Six collections were made on each of 95 days, giving 570 observations and a total of 29 378 Culicoides. Two collecti ons were made before, one at, and three after sunset. Separate analyse s were made of the catches of thirteen entities: male and female C. au stropalpalis, C. brevitarsis, C. marksi, C. mamoratus and C. victoriae , female C. henryi and C. longior, and total C. bundyensis. Catches,we re dominated by C. brevitarsis (35.2%) and C. marmoratus (32.3%) and, with C. victoriae, were taken on almost every collecting day over all seasons. Sex ratios (M:F) varied from 0:100 for C, longior to 130:100 for C. marksi. Collections of all entities, except female C. henryi, w ere greatest (50-70% of the daily catch) at sunset. In winter there wa s substantial activity in the hour before sunset. Time of day was the most important variable, accounting for 15-45% of the observed variati on. Between-day differences were significant for all except C. austrop alpalis, C. victoriae and male C. marksi. Culicoides brevitarsis, C. b undyensis and C. longior had highly significant annual cycles, C. vict oriae and female C. austropalpalis had significant lunar cycles, and C . longior had a significant tidal cycle. Logarithms of catches of fema le C, austropalpalis, C. brevitarsis, C. henryi, C. marmoratus, and fe male and male C. victoriae were inversely related to linear wind speed . Log catches of female C. austropalpalis, C. brevitarsis, C. marmorat us and C. victoriae, and male C. marksi and C. victoriae were positive ly related to temperature (quadratic).