Age-Related Adult Activity and Sugar Feeding by Culicoides Variipennis (Diptera: Ceratopogonidae) in Southern California, USA

Adults of Culicoides variipennis were collected with 6 CO2-baited traps placed in an east–west transect across a breeding site in southern California, USA. These insects were active over the entire 12-month sampling period but were less abundant in late winter. Gravid females also could be collected year-round near the breeding area by sweep net, which indicated some level of successful blood feeding. Ovarian dissections revealed some females with as many as 5 dilatations in August and November. Anthrone tests detected simple sugars in males (11%), nullipars (12%), and pars (24%); sugar positivity increased during winter and spring. Traps placed directly adjacent to the breeding pond generally collected fewer flies with a higher level of parity than did those placed 50 or 100 m away. Nullipars and males showed a tendency to disperse upwind in the vicinity of the breeding site. Trap location thus is a potential source of sampling bias for survivorship studies in this species.