Thursday, 3 October 2013

The Sore-bottomed Shieldbug

This isn't its recognised name of course; I am referring to the Hawthorn Shieldbug, with its curious Latin name of Acanthosoma haemorrhoidale. The genus name is straightforward, for 'acanthosoma' simply means 'spiny bodied'. It is the species name which is puzzling - until, that is, the rear end of the bug is examined. It is a bright pink, leading Linnaeus - who must have had a sense of humour - to conclude that the unfortunate creature was suffering from piles!

As one would expect, this bug is common on hawthorn bushes although observations made in Surrey ("Shieldbugs of Surrey" by Roger Hawkins) show that it can be particularly abundant on some species of Cotoneaster, especially Cotoneaster x watereri. I saw it in Byfield Pocket Park earlier today on Bramble and it kindly sat still while I photographed it.

Hawthorn Shieldbug, Acanthosoma haemorroidale
Byfield Pocket Park.  3.October, 2013

September is the best month to see this bug. Odd specimens turn up at other times of the year but adults are most numerous in early autumn. They then go into hibernation in late October. This is quite a large bug, but its chestnut-red and green body matches the berries and leaves of hawthorn and it can quite easily be overlooked. As with most of its relatives, any attempt to handle it will leave a pungent smell on the fingers - the same smell that deters would-be predators

Hawthorn Shieldbug, showing its "sore bottom"
It is necessary to turn the bug over to see the red patch at the base to the abdomen. (Bug-lovers will be pleased to know that, having had its nether regions photographed, the plucky creature recovered and I was able to set it free.)