Scientists are driving around the countryside with a giant net attached to their car in a bid to discover how midges spread the bluetongue virus.

Researchers from the Institute for Animal Health are trapping and monitoring the midges so they can advise farmers how best to protect livestock.

The team has developed two methods to monitor the flying and biting behaviour of the Culicoides midge that spreads bluetongue.

The first method uses a large net of known volume mounted on top of a 4x4 truck, which is driven through grazing land.

By driving at a constant speed of 20mph, the scientists can calculate the number of midges for each cubic metre of air passing through the net.

The second method focuses on the biting rate of the midges.

It uses a large muslin tent, the walls of which are lowered around a penned grazing sheep after an exposure period of ten minutes.

The scientists then collect any midges that have landed on the walls and ceiling of the tent before examining the sheep for any further biting individuals.

Midges are analysed in the laboratory to establish which species is carrying out the biting.

Lead researcher Dr Simon Carpenter said:  “These experiments are vital - it's about knowing your enemy.”

Data from midge-hunting expeditions in southern England is then incorporated with meteorological data from the Met Office.

This is used to forecast when the midges are mostly likely to be flying around and bites farm animals.

Last year, bluetongue cost livestock farmers in northern Europe more than £95m in direct losses.

UK farmers are being urged vaccinate their stock ahead of the peak time for bluetongue, which is due later this month.