Sunday, 29 August 2010

The Wart Biter

The French nature guides call it ‘verrucivore’. The locals just call it a ‘sauterelle’. It is a relatively common beast in the area where I live. In Britain it is rare and in France is said to be declining.
If you have ADSL internet connection, I suggest that you look at this site:--
It shows an intriguing short video by Dr. Simon Robinson, senior keeper at London Zoo, of the activity of this animal chewing away at a wart on his finger.
The beast which when placed near a wart on the skin actually seeks it out and chews it! It then in this instance regurgitated its stomach contents over the wound which caused Dr. Robinson considerable pain.
I suspect that the extraordinary activity of this creature was discovered by chance in Scandinavia, but did this knowledge anciently reach France? The French nature books have surely borrowed the French name from the Latin. Linnaeus, who gave the Latin name, was a Swede, and he would know of this folklore, and he named it ‘Decticus verrucivorous’ , which also means ‘wart-biter’. A French text states “It is usual to let the insect chew the wart and then burn the wart by deposing the stomach contents on it”. Have there been then dialect French names now lost to us?
What, one wonders, attracts the beast to a wart? What is in the gut contents to cause such pain?
The photo shows a female with its long ovipositor sitting on a vine leaf. She will lay eggs singly in the stony ground. After hatching, the young will take over a year to mature, attaining a size of up to 4 centimetres. Note the blocky pattern of black and white on the wings, and also note the very long antennae. Together these characteristics will distinguish the creature from other grasshoppers and crickets. [N.B. the French word ‘criquet’ indicates the grasshoppers which carry short antenna - Crickets with long antennae are ‘sauterelles’ in French.]
This animal is a relative of the Great Green Cricket, which is one of noisiest chirpers day and night. This one is equally loud but with a rhythm of notes of an increasing rapidity. These ‘chirps’ are produced in full sun only by a males as he moves his left wing which bears a toothed rib rapidly over the hind edge of the right wing.
There is no point in sounding off unless the female can hear! These insects have ears which are found on the front legs just below the front knees. But things are more complicated even than that. The ear structure is rather like an ear trumpet in form. The wide end is not on the leg but on the thorax under the side flap which extends down from the back. There is an opening on each side which leads into an ear tube which in an ever decreasing width leads down to the leg and ends up between two slits which are visible below the knee. The sound is by this means amplified when it gets there. Oscillating membranes vibrate to the sounds and nerve endings send messages to whichever part of the nervous system is programmed to respond.