Effect of Temperature on Life History Parameters of Adult Culicoides sonorensis (Diptera: Ceratopogonidae) in Relation to Geographic Origin and Vectorial Capacity for Bluetongue Virus

Abstract

The effect of temperature on survival, oviposition, gonotrophic development, and a life history factor of vectorial capacity were examined in adult Culicoides sonorensis (Wirth & Jones) (Diptera: Ceratopogonidae) that originated from two geographic locations. Flies originating from the United States (Colorado) had slightly reduced survival after a bloodmeal compared with wild ßies collected in southern Alberta (AB), Canada. Survival of AB ßies declined in a curvilinear manner with temperature, whereas survival of U.S. ßies showed a linear response to temperature. The survivorship curve of the AB ßies more closely followed a Weibull distribution than an exponential, indicating survival was age-dependent. Survivorship of the U.S. ßies followed an exponential distribution. Females from both sources laid similar numbers of eggs throughout their life. The Þrst eggs were laid by females from both sources at 31.9 degree-day (DD) 9.3. Dissections of blood-fed ßies reared at various temperatures indicated that ßies from both sources were 90% gravid at 32 DD 9.3. Relationships among temperature and life history components of vectorial capacity were similar among ßies from the two sources and indicated that vectorial capacity would be 1.8Ð2.6-fold greater in a southern U.S. climate compared with southwestern Canada due solely to the effects of temperature on the life history of C. sonorensis. Using life history estimates derived from Weibull model had little effect on estimating vectorial capacity, whereas using estimates derived from the exponential model slightly overestimated vectorial capacity.