Looking for Bert the Gorilla

By Brett Westwood

Somewhere deep in Worcestershire’s countryside, Bert the Gorilla is lurking . He’s more likely to be in your garden or greenhouse than in the more rural spots, so while the foot-and-mouth restrictions remain, you could do worse than take up the challenge and start a ‘gorilla hunt’ this summer.

The more perceptive of you will have cottoned on to the fact that we’re not talking primates here. Bert the Gorilla is really a slug, the worm slug to be precise, and glories in the name of Boettgerilla pallens. It’s a small creature, up to 4cm when fully extended when it looks remarkably worm-like . It’s mostly pencil- grey on the back and head with a pale yellow sole and colourless mucus and looks immediately different to the other slugs you’re likely to meet in the garden.

Worm slugs are recent introductions to the British Isles from their native haunts in south-eastern Europe and have probably spread as adults through nurseries, as eggs on the soles of shoes or in garden rubble. In Germany Boettgerilla is now one of the commonest slugs and it has even reached the United States where biologists are worried that it may become a serious pest. The first British record was from the Lake District in 1972 and since then it has spread rapidly throughout Britain and southern Ireland.

Worcestershire records are apparently absent (we have discovered one record in Worcs BRC files - in 1982. See our web site for a list of Mollusc records - Ed), but worm slugs are certainly present in the vice-county and waiting to be unearthed. They can burrow deep into the soil like earthworms but also occur at the surface under wood and stones. Greenhouses and cold-frames are a popular habitat and allow the slugs to survive in otherwise unfriendly climates; in Finland most records are from these places.

So, there’s the challenge. Can any Worcestershire recorder locate Bert this year? Fame ,and for all I know, fortune, awaits the lucky finder. Please send your records to the Biological Records office and we hope to bring you an update on findings this time next year.