Biting midges (Ceratopogonidae: Culicoïdes) in Belgium: a comparison between indoor and outdoor trapping in cattle and sheep farms.

Bluetongue, a vector born disease of ruminants, was identified for the first time in Northern Europe in 2006. The vectors are insects of the family Ceratopogonidae, genus Culicoides. In Belgium, no recent data were available about the biology of these insects including their feeding habits and behaviour. The present study was carried out in order to evaluate the indoor and outdoor activity of these Diptera in 5 different cattle or sheep farms in 2008. Two sheep and 3 cattle farms were selected in the Province of Luxembourg, Belgium. In each farm 2 Onderstepoort Veterinary Institute (OVI) traps were installed respectively inside and outside the animal accommodation. Trapping was carried out twice a week from 17:00 until 24:00.The collecting vials were replaced every hour. A portable suction trap (BackTrap® U.S.A) was used twice on each visit to collect midges on the animals. In each farm the study was carried out for 6 successive weeks, 2 farms being monitored together. The study began on July 28th and ended on November 30th 2008. A total of 2591 culicoides were trapped. A majority of those (88.76%) were trapped indoors whereas 10.03% were trapped outdoors and 1.21% directly on the animals. The ambient temperature had a marked effect very few culicoides being trapped below 13°C. Three main species or species complex were identified both indoors and outdoors: C. obsoletus/scoticus, C. dewulfi, C. chiopterus. They represented 98.93% and 85.03% indoors and outdoors respectively. On the animals only C. obsoletus/scoticus and C. dewulfi were found.