Europe's largest insect charity, Butterfly Conservation, is keen to hear of any other sightings of the geranium bronze and monitor its introduction to Britain. John Holloway, a member from Lewes, recently spotted more than half a dozen of the dark-brown and bronze African butterflies in his garden.
Large numbers of eggs have been laid on cultivated geranium plants - the butterfly's caterpillar food plant in South Africa. It is believed the geranium plants and the butterfly were imported from the Netherlands.
It is the first record of the geranium bronze breeding in Britain, although it bred in the Balearic Islands in 1989. The tiny butterfly, which has a 2cm wingspan, is a slow flier and is usually found only south of the equator. Experts believe its European introduction is entirely man-made, due to the popularity of geraniums and pelargoniums as garden and window- box flowers.
Gary Roberts, of Butterfly Conservation, said: "In the Balearic Islands the geranium bronze has reached pest proportions because it has no natural predators there. The caterpillars bore into the stems of geraniums thus causing that part of the plant to die.''
The chances of the butterfly surviving a British winter is remote. Geranium plants can rarely tolerate British winters and usually need to be kept in heated glasshouses.Reuse content