Culicoides in the UK are active between April and November, particularly on humid days, feeding at dawn and dusk, however, in the tropics these midges can be active all through the year. It is only the females that blood feed and are known as interrupt feeders. This name comes from how they feed, they will inflict a painful bite and as they do so they will cut the skin and capillaries with their mandibles to form a blood pool. The bite causes the horse to be agitated, bite or kick the area which interrupts the midge in its feeding and so it moves onto the next horse.

 

The biting midges known as Culicoides are from the family Ceratogoponidae. They are tiny flies of approximately 0.6 – 5.0mm in length, they have a humped thorax, small head and short legs. Their wings have a mottled pattern with microscopic hairs covering them. During rest these wings are held close over the body. They have small mouthparts with long antennae, in the males these antennae are feathery and known as the plumose antennae where as in the females the antennae have short hairs and are known as pilose antennae.

 

Culicoides breed in moist grounds around puddles, ditches, marshes and standing water. Their eggs hatch in 2-9 days and once hatched there are four larval stages that have a serpentine swimming action in water. In warm countries the larval development is completed in 14-25 days but in more temperate areas the development can be delayed up to 7 months.