Nature Notebook

Leopard Slug © Wendy Carter

Secretive Slugs

Not all slugs munch your dahlias and many recycle nutrients back into the soil...

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Worcestershire Wildlife Trust @WorcsWT t worcestershirewildlifetrust G worcswildlifetrust.co.uk w Slug. Even the word isn’t particularly pleasant. Slugs have got a reputation for being the gardener’s nemesis but these nocturnal creatures deserve more respect. Leopard, ghost, hedgehog, silver, dotted, lemon…there are more than 40 species of slug in the UK and it’s time that we got to know them a little better.

Slugs are gastropods, which means ‘stomach foot’, referring to the fact that their ‘foot’ basically runs underneath their tummy. This muscular foot is eased across surfaces by the production of mucus, which is what produces the slimy trails you sometimes see. Slugs also use this for navigation; the trails help them to find their way home and to locate other slugs.

Slugs have evolved from snails and still carry a muchreduced shell within their bodies. They have two pairs of tentacles at the front – the upper pair are used for vision and smell whereas the lower pair focus on touch and taste. Although they’re hermaphrodites, which means that they have both male and female reproductive organs, they need another slug in order to mate. When they do, both slugs become pregnant!

Check in damp and dark places – under stones and logs, in compost bins or buried in the soil – and you’re likely to find a slug or two. Rather amazingly they have almost as many teeth as a great white shark and they use these to rasp away at their food. Contrary to popular belief, many species of slug shy away from your prize plants in order to feed on rotting vegetation, lichen, fungi and decaying organic matter. In fact, they’re one of nature’s recyclers and brilliant composters, turning all this food into nutrients for gardens and soils. Leopard slugs even eat other slugs!

Slugs are less active when it’s dry or very cold but who knows what this year’s weather still has in store for us. For slugs that weren’t able to retreat to a sufficiently damp area during the summer’s heatwaves, disaster may have already struck. On the other hand, a damp and mild autumn might see slugs out and about for some time to come. This could be a good thing for other wildlife as slugs are food for birds, hedgehogs, slow-worms, toads, beetles, badgers and foxes. It’s estimated that a garden might have around 20,000 slugs, which just goes to show what an important part of a healthy and productive ecosystem these glistening trail-makers are. Whilst some slugs do eat plants, instead of trying eradicate them from your garden, think about how best to restore balance between prey and predator. One slow-worm on a Worcester allotment was seen to eat 17 slugs in one sitting, for example.

As well as encouraging slug predators into your garden, try planting strong-smelling or hairy plants (lavenders, rosemarys, cranesbills) around your favourite plants. Slugs prefer not to travel over rough ground so using crushed eggshells, gravel or woodchip around your prized plants might help. For top tips on making your garden attractive for lots of different species, take a look at www.worcswildlifetrust.co.uk/wildlife-gardening n