Horseflies. The ubiquitous scourge that many horse owners dread meeting. Silent and persistent in their chase, with mouthparts like pneumatic drills, ready to inflict nasty bites and painful itchy swelling. But how much do we know about these fiends in insect form? Well, we know there are about 30 different species of horsefly in the UK, that they are typically between 8-20mm in size and that your blood, and that of your horse, goes towards the protein they need to develop eggs.
Horseflies have great eyesight, using contrast, movement and heat to find their next blood meal. If you think you are being chased, you probably are. Only the females of the UK species blood feed, with the most common species Haematopota pluvialis (the cleg) particularly partial to human blood.
Warm temperatures and still days are the preferred conditions for horseflies, with adults emerging in the early morning on hot summer days.