A Taste for Blood

Originally published September 2011

Hello everyone! I hope the Summer has been enjoyed by one and all and that you are eagerly anticipating Ma Nature’s season of bounty and fruitfulness.

TQW - Sep 2011 - PaulLast month I was fortunate enough to spend a couple of weeks on the lovely island of Corfu in search of the land of Durrell’s My Family and Other Animals. Whilst there I found myself pondering a question I often hear people asking; usually in a fit of angst. This particular qustion being: what on earth is the point of some creatures, what use are they? Not an appropriate train of thought for an ecologist you may think; and you would be quite correct. After all if organisms were judged on their contribution to the welfare of the planet, where would that leave Homo sapiens sp.?

In my defence I must explain that I warmed to this theme whilst applying liberal amounts of ineffective Mosquito repellent and subsequent layers of after-bite gel to my ravaged skin. My mind wandered to former days in Midlothian when I swathed myself in layers of clothing in order to carry out fieldwork amidst swarms of the infamous Scottish Midge. How fortuitous, I deemed it, to be living in a part of the country where bites and stings are relatively uncommon. Where the sight of a couple of dozen Gnats dancing in the last rays of a Summer sun is a pleasure to behold. My hour of great disillusionment came a few days ago as I bent down to photograph some fungi in our little reserve and received five insect bites in a matter of seconds!

So, in an attempt to put things in perspective, let us first of all consider what these little tormentors actually are. Well taxonomy is nothing if not complicated and in this case not overly helpful as far as we are concerned. Mosquitos, Midges and Gnats belong to the Culocomorpha which is an Infraorder of the Nematocera which is a Suborder of the Diptera which itself is an Order of the Class Insecta. Not too enlightening perhaps but it gives us a starting point. The Diptera (from the Latin Di– two + ptera-wings) are the True Flies, those with just one pair of wings as opposed to Dragonflies, Damselflies, Stoneflies etc.

Publication1

In global terms this categorisation of these insects is particularly important as (in my opinion) the most dangerous animal on the planet is found among the Culocomorpha, the Anopheles Mosquito. This species is the carrier of the parasite Plasmodium sp. and thus the only known vector for Malaria. Roughly about half the population on the planet is at risk of this disease and the mortality rate is staggering with up to 1,500,000 Malaria deaths a year. Historical records show that the disease was prevalent in Britain right up to the early part of the 20th Century; although it went under many names such as the Ague, the Shakes and Marsh Miasm. The decline of Malaria in the UK has been attributed to the the draining of many of the water catchment areas such as a large part of the Fens and the traditional water meadows, combined with the rise in the number of cattle. Mosquitoes usually prefer cattle to people as their meal of choice and it seems that the intensification of farming has diverted their thoughts away from us to some extent.

Of course Mosquitoes are only one of many biting insects in this country, Midges, Gnats, Black Fly and several other True Flies can make a day in the countryside very uncomfortable indeed. In all cases it is the female of the species that bite as they need the proteins gained from the gruesomely named blood meal before they can lay their eggs. Over the centuries people have smothered themselves with everything from hedge clippings to animal dung and eaten onions and garlic by the string load in an attempt to deter these mini beasts. One west country brewery has even named a beer after the local Fly claiming that one of the constituents of ginger, a chief ingredient, will bring relief to the afflicted.

With regard to the original question of usefulness of the the species it would appear, given all the adverse publicity, that the odds are stacked against the Diptera. Nevertheless, it cannot be denied that both the larval and adult stages are eaten by very many species of fish, amphibian and bird. The sunlit dance of the Gnats is overshadowed by the evening antics of Swallows as they swoop and glide eating Mosquitoes on the wing. On warmer days the insects are swept upward on thermals allowing the birds to feast further from the ground; giving some credence to the folk lore regarding Swallows and weather prediction. However, given our erratic climatic conditions, do not look to the birds before planning your weekend picnic!

So there it is, a very brief sortie into the world of the least popular denizens of the countryside, but only as far as the anthropocentrically inclined are concerned!

TQW hobbit‘Midgewater! There are more midges than water!’
‘What do they live on when they can’t get hobbit?’ asked Sam, scratching his neck.
The Fellowship of the Ring, J.R.R. Tolkien

Enjoy the reserve, but cover up! Put me right at pgcrow@yahoo.com

Paul Johnson

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Image 2: Mosquito by Ramon Portellano, used under Creative Commons License 2.0 / Image 3: Fungus gnat by Andy Murray, used under CC2.0 / Image 4: Midge (Chironomidae) by Walwyn, used under CC2.0


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