Derek – Friday 13th August 2021

The brown slug (Arion ater) that I thought had been eaten by a bird has re-appeared, or perhaps it’s not the same, as I see another shortly after. The former is about as long as my middle finger, plump as a chipolata. The back half of its body has ridges rather like a fingerprint, but I can’t see any purpose in them. They don’t help it grip, as it moves on its underside on a layer of slime.

There are two pairs of tentacles coming out the front of its head. The upper ones have eyes at the tip, the lower are olfactory in function, pointing to the ground, smelling out food. This slug is out in daylight, a dangerous activity, you might think, were it to be spotted by a bird. But it is coated in a sticky, unpleasant tasting mucus which deters many potential predators. Not all, as hedgehogs, moles and some birds will eat them in spite of it. When it is picked up or touched, it will contract to a hemispherical shape, making it like a ball of goo. A few weeks ago, I picked one up, and put it down pretty quickly as it is so slimy. I found the slime difficult to wash off.

Arion ater is a hermaphrodite, laying eggs over spring and summer every one to three weeks. So there could be a lot more around the garden, apart from the few I have seen. I would have to come in the evening with a torch to get a better idea of numbers, as it is mainly nocturnal.

Between the head and the ridged area is an ovoid, indented area, the pneumostome. This is the hole to allow air to get into its lungs. Although they eat vegetation and decaying material, the brown slug (or the black which is a variation) is not the gastropod doing most of the damage in the garden. That’s the garden snail (Helix aspersa), the large common snail; the garden appellation denoting how common it is. ‘Garden snail’ as a name is somewhat unimaginative. It sounds as if I don’t know what it is and have just lumped it with every other snail in the garden: it deserves better. Ditto the garden spider (Araneus diadematus) now coming into its own, growing rapidly as its mating season approaches, with webs all over the garden.

I am shown a black sphere, about half a centimetre in diameter, found in the compost. Could it be a seed? But then I note it is scaly. And I think it is a pill woodlouse, which rolls into a ball when threatened. I set off to get a book to confirm this when the sphere begins to unravel in my hand, its many legs waving wildly as it turns over. Was it the warmth of my hand that caused it to open up or just time, as sooner or later it must reveal itself?

At home, I check its ID, and find it is actually a pill millipede. This is distinguishable from the pill woodlouse by having many more legs and a black shiny colour. The former is grey.

We have acquired another plastic metre cube. We will be needing it soon, as Gateway which has supplied our water tap will be completing work on the neighbouring site in the next few weeks, and will be disconnecting us. From then on we’ll be dependent on rain water to keep the garden plants alive.

The metre cube illustrates the simplicity of the metric system as opposed to the Imperial system. The cube is 1000 litres in volume, or a million millilitres. A level teaspoonful is about 5 ml, so it would take 200,000 to fill it. I might drop Hades a line, to suggest an alternative job for Sisyphus.

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