In a new development to my investigation into the diet of the impressively sized Leopard slug, last night I found one apparently feasting on it’s prey.
I know: I should probably get out more (by which I mean, beyond my back garden)!
I Can’t know whether this Leopard slug actually made a kill, or just encountered a dead slug and thought it would have a nibble, so I suppose this is only circumstantial evidence. When I shone the torch on it, the leopard withdrew it’s antennae (I believe the correct term is actually tentacles, but I prefer antennae), but I’m sure it was eating. I was outside for a while, and each time I went back it was still there.
There’s an extensive Wikipedia entry for the Leopard slug (Limax maximus) which, along with other sources, confirms that the Leopard slug eats dead plants and fungi and is also a carnivore ‘known to pursue other slugs at a top speed of 6 inches (15cm) per minute’ (watch them go!)
Disturbingly, the Wikipedia entry says that ‘it also eats young crops faster than they can grow and so is listed as a major agricultural pest by state departments of agriculture in the US from Florida to Oregon’. Having been taught never to rely on Wikipedia, I checked this out, and there doesn’t seem to be much evidence to back it up (even in the documents the Wikipedia entry cited). One archived document did say it was an ‘important pest of gardens, greenhouses, cellars and mushroom beds’, but failed to mention it’s predatory tendencies, so may not be a reliable source. I did find an Oregon Department of Agriculture ‘Guide to Slugs and Snails in Oregon’, by Joshua Vlach (1.), which said it’s diet is ‘primarily fungus, but also decaying plant and animal material, and occasionally green plants’. Which doesn’t suggest it’s a serious pest, but does back up my initial instinct to think that while some slugs may at times eat other things, the slug that won’t nibble on your precious plants if they get the chance doesn’t exist. So maybe after all the best type of slug is a dead one!