The Blandford Fly

As a river angler, and one who fishes the Stour on occasion I was rather surprised to see that the Blandford Fly is so called as it is most prevalent around the village of Blandford Forum in Dorset, and the whole of the lower Stour area is considered as its breeding ground. Indeed, there are many instances of people being bitten right down as far as Bournemouth.

Here are some of the facts that I have managed to find on Internet, so I claim no authorship whatsoever, and will quote the sources accordingly:

From the Modern Dorset website (www.dorsetshire.com/new/new.html)

In case you’re wondering, it is a nasty little insect flying close to the ground and feeding on human blood. The proper name is Simulium posticatum. The danger period used to be from about 10th May until mid-June, but now it seems to be all summer. You seldom notice it until it’s gone, leaving a spot of blood, then spend the next week nursing anything from an annoying itch to a large incapacitating swelling. Supposedly inhabiting cracks in the mud on the River Stour’s banks, there has been a campaign to eliminate it by spraying the banks; it seemed to be working up until 1997.

How to avoid being Bitten

1. It only flies close to the ground; Cover up exposed flesh from the waist down. Do not lie on the ground or on a low sunbed. If you’re bending over e.g. gardening, cover up your arms.
2. If you still feel at risk, use an insect repellent. I prefer the free one, which is tansy plant (grows as a weed in the garden) rubbed hard into the skin – not pretty but smells strong.

From the Whitecliff Practice website (www.whitecliffpractice.co.uk)

The male flies of most species collect in huge swarms which, on calm sunny days, dance in the air near trees or buildings, awaiting the arrival of the females. The female flies enter these swarms and are seized by a male before the mating pair falls to the ground. Before or after mating the female flies frequently seek a meal of blood to supplement their diet and assist in the production of eggs. Each of the many species has a preferred host on which it will feed. Hosts include reptiles, birds and mammals such as deer, horses, cattle or sheep. In the case of the Blandford Fly the main host is man.

It is the bloodsucking habit of the female Blandford Fly that causes a major problem to people living in South Dorset. Almost exclusively in May and June the flies range far and wide in search of someone to bite. The insects tend to fly less than half-a-metre from the ground and so most victims are bitten on the legs. The bite itself can feel like a painful stabbing sensation and the saliva of the fly, which passes into the wound, often causes severe irritation, pain, swelling and blistering. To reduce the chance of being bitten it is a good idea to wear trousers, to apply insect repellent and to avoid open areas of garden, parkland or river bank particularly in fine weather in the middle of the day. (Unlike mosquitoes biting activity is least in early morning and late evening).

Having satisfied its craving for human blood the female must wait for its 200-300 eggs to mature before returning to the river to place them in the desiccation cracks of the steep, shady river bank, well above the summer water levels. The egg laying females crawl deep into the cracks and stick their egg masses to soil particles in moist humid conditions. The eggs are laid in June and July when the weather is warm. They begin to develop at once but when the eyes of the embryo can be seen through the eggshell as little red dots, development stops. Only a spell of cold weather after the onset of winter will trigger the eggs to progress further. After a few weeks of chilling the eyes blacken and, by February, fully developed larvae with black, thorn like egg-bursters on top of their heads are visible through the translucent egg shells.

Treating a Blandford Fly bite

-Clean the bite wound with soap and water and dry gently.
-Creams that contain camomile lotion, steroid cream, or anaesthetic can soothe the pain of a bite, as can an antihistamine tablet.
-Do not apply cream or ointment to broken skin and always follow the instructions on the packet. Try to avoid scratching the bite- although it may be very itchy – because you may damage the skin and allow bacteria to get in.
-Redness and irritation are common and should settle within a few days with these measures.
-Secondary infection is less common. If you notice red lines appearing on the skin or enlarged lymph nodes (swelling) in your armpit or groin, please see your GP.

From the BBC Website

‘District’ fly bites elderly man’
A 73-year-old who became seriously ill after being bitten by an insect in his Dorset garden has claimed the bite was from the so-called Blandford fly.

After four days on an intravenous drip of antibiotics at Dorchester’s Dorset County Hospital, Peter Dunn believes he is “lucky to be alive”.

Mr Dunn, from Bridport, initially thought it was a mosquito bite on his leg but the infection kept spreading.

Historically, the small black fly has been more prevalent in North Dorset.

Larvae are sprayed
North Dorset District Council manages and contributes more than £ 8,000 a year to an aggressive treatment of rivers because “the concentration of the insect has traditionally been highest in the district”.

The insect takes its name from the town of Blandford, where its larvae breed in the weed beds of the river.

The larvae are sprayed as they emerge from the Stour in late April to prevent them reaching adulthood and causing a nuisance to residents.

There have been considerably less bite reports from members of the public than there were in the late 1980s – in 1988, more than 1,400 people were treated in hospital after being bitten by the fly – and this is due to the treatment, said the district council.

There have also been fatalities as a result of the bites.

Further reading

www.north-dorset.gov.uk

www.bbc.co.uk

http://en.wikipedia.org

Finally, I hope that the above will help to inform all FM readers of the potentially lethal consequences of being bitten by one of these insects. I have carried a comprehensive first aid kit in my fishing bags for many years, and I would urge all anglers to make room for one as well.

Dave Colclough RIP