Tree Slugs

A group of Tree Slugs, Lehmannia marginata.  Hayes Common, 1 January 2013.

There is not much activity in the wild at the moment, from my point of view, though no doubt the bird fans are having a good time.  Also, I have been busy for a week or so revamping the Orpington Field Club's website, which I have taken over.  So there's not much activity here either.  But this was something I hadn't seen before.

These slugs live on lichens, algae and fungi, all of which they can easily find on the trees where they live.  But I don't know why half a dozen of them should have been making their way downwards in a group. 

They are quite well disguised, but they glisten, which drew my attention.

Identification Answers

Fungi and Other Goodies

OK!  Quiz answers!  The fungi in this group are numbers 1, 2 and 6.  1 is a Small Stag's-horn Fungus, Calocera cornea; rather immature.  2 has the delightful common name of Crystal Brain, and can also be called Exidia nucleata.  6 is a Pale Staghorn,  Calocera pallidospathulata.

Number 3 had me excited when I saw it in wet rotting wood.  But on closer examination it turned out to be two holly berries that had fallen from the bush above.

I found Number 4 by turning over a piece of fallen wood.  It is a cluster of slug's eggs.  I don't know what species.  They will be familiar to most gardeners.

Number 5 is probably a bit of a trick question.  It's a Myxomycete, or Slime Mould, most likely a species of Trichia; it would take an expert with a microscope to determine which species.  Although Slime Moulds are often lumped in with fungi, because they have a lot of superficial similarities and they grow in the same places, many biologists think that they actually belong to a different kingdom and are related to Amoebas.  Some of them are quite mobile for part of their life cycles.  But they also reproduce by disseminating airborne spores, like fungi.  They are truly odd.

Two Garden Slugs

Large Black Slug, Arion ater, going for a chunk of mango in my back garden in Hayes, 7 September 2011.

I used to pick up the big slugs in my garden and throw them over the back fence into a patch of scrub and trees, but then I read that some of them eat the smaller slugs that do most damage to garden plants. Since then I have let them be, and there does seem to be a lot less slug damage.

The creature in the top photo is called the Large Black Slug, but actually varies in colour. Back in Newcastle, they were all jet black. Here, they are mostly this mid-brown, though some are more yellow.

You can clearly see its mantle, its breathing pore and the stripy fringe. At the end of the tail is a little lump of mucus that picks up bits of the environment; bits of grit and plant debris in this case. This slug eats vegetation and carrion, but will not actually attack living prey.

Below is a Leopard Slug, so-called because of its appearance, but this one is also an active predator and goes after the little slugs as well as carrion. A group of these spend the day under the rim of my rainwater butt, cool and wet. Welcome to the garden, Limax!

Leopard Slug, Limax maximus, in my back garden in Hayes.  25 September 2011.

Slug and Snail

A slug and a snail in my back garden in Hayes on 8 September 2011.

To get a good look at the slugs and snails that live in your garden, leave a piece of squashy fruit out on a wet night. These were attracted to a piece of mango, the bit that surrounds the large stone in the middle. After a couple of nights, the stone was cleaned off quite thoroughly.

I do not know their species, though I think the slug is a Garden Slug, Arion hortensis. But they have a delicate beauty, particularly the snail, with its varicoloured shell and those grey streaks that lead from its eye-stalks down along its body.