The effect of climatological factors on the seasonal dynamics of dominant Culicoides (Diptera: Ceratopogonidae) species in Bidar, Karnataka

A study has been conducted in Bidar, India to know the effect ofclimatological factors on the seasonal dynamics of dominant Culicoides species. The midges were collected at fortnightly intervals using a down draught light trap (220 Volts) from June, 2004 to July, 2005. A total of 27 collections were made and 221990 (Mean ± SE= 8,221.85 ± 2,270.10) midges were collected. A portion of midges from each sample were analysed for species composition. Culicoides imicola and C. oxystoma were the two species that appeared consistently throughout the study with percentages ranging from 9.59% to 79.57% and 17.07% to 83.11% for both the species respectively. The association between the climatic factors and these species revealed significant negative correlations between temporal abundance of C. imicola with maximum temperature and wind velocity and significant positive correlation for relative humidity. There is no significant inftuence of climatic factors on temporal abundance of C. oxystoma. Based on these results it is being concluded that there is continuous availability of Culicoides midges in the present locality, which indicates the continuous availability of breeding places. Culicoides imicola and C. oxystoma were considered dominant species. Climatological factors have significant inftuence on seasonality of C. imicola but not for C. oxystoma. Further detailed analysis of these two species will yield a better clarity on their vectoral role for the disease like bluetongue in this region.