Local Dispersal of the Biting-Midge Culicoides-Brevitarsis Kieffer (Diptera, Ceratopogonidae) in Southeastern Australia

Abstract

C. brevitarsis 'rested' in the ground herbage during the day and flew just before dusk and during the evening and night, when air temperature was above 18°C and wind velocity was below 8 km h-'. More females were caught in light traps with 6-V 18-W globes than with 7.2-V 3-W globes. Only the light ventral to the traps played a part in catching this biting-midge. More were captured with the 120°-traps, which illuminated a 10-m circle of herbage beneath, than with 40°-traps, which illuminated a 2-m circle. Covering up to 20 by 20 m of the ground beneath 40°-traps with opaque plastic or setting these traps in ploughed paddocks, 40 m from any ground herbage, gave collections of females similar in numbers and population structure to nearby collections over grass. Nulliparous and parous females, empty, blood-fed and gravid, were captured at 2, 4 and 6 m above the ground. Females were shown to congregate around cattle to feed, to oviposit, and to maintain contact. Dispersal in the wind is an integral part of the biology of C. brevitarsis.