Snail

We found this delightful little snail, just 16mm. long, on  a dead tree in Thorsgill woods in Teesdale recently. 

It's called Clausilia dubia, according to the excellent  Field Studies Council ID guide for land snails.

Upwardly mobile snails

One of the stranger sights of autumn is the way in which snails seem to have a compulsion to climb to the top of hogweed Heracleum sphondylium stems during wet weather. These are just a few of over 50 that I counted on a single hogweed plant recently.

They seem to have a passion for the thin layer of soft rotting tissues on the outside of the dying plant's stem.

Cold-Blooded and Spineless

Last Friday saw the launch of the North Pennines Area of Outstanding Natural Beauty Cold-Blooded and Spineless project. Over the next five years it will train volunteers and local wildlife groups to identify and map the distribution of invertebrate animals in the AONB, as well as working with schools and artists to encourage them to appreciate and celebrate the wealth of  smaller elements in the wildlife of the region.

You can read much more about the project at http://www.northpennines.org.uk/Pages/Cold-bloodedandSpineless.aspx

After the various presentations at the launch, held at the Environmental Centre at Harehope Quarry near Frosterley in Weardale, we went on a short bug hunt. Predictably, there weren't many flying insects about in mid-March, although someone did catch this male mosquito with rather magnificent antennae.

But when we started turning over stones it was a different story.

Lots of ants

A common pygmy woodlouse Trichoniscus pusillus

I think this one is a young specimen of the common shiny woodlouse Oniscus asellus

Lots of black snake millipedes Tachypodoiulus niger

More millipedes, that I've yet to identify

Two very small snails, awaiting identification

Several species of springtail. In the picture above, showing the underside, you can see the forked furca folded under the tail, that it uses like a pole-vaulter's pole to catapult itself into the air.

Click here for more about springtails

A very fine devil's coach horse, with a formidable pair of needle-sharp jaws

Click here for more about devil's coach horses

Numerous ground beetles, including ....

..... this one that played possum when it was turned onto its back, and ... 

.... this one, that was carrying a hitch-hiker on its back, which ...

... looks like it might be a very small tick.

I haven't had time to ID these properly yet, but am posting them now so that those who found them can download the pictures.

It's amazing what you can find if a dozen people spend half an hour turning over stones, even if it is a cold March afternoon!

If you'd like to know more about the Cold-blooded and Spineless project, or would like to become involved, contact samantha@northpenninesaonb.org.uk 

Under the skin of a sycamore

Thursday's Guardian Country Diary is about the remarkable range of small invertebrates that live under the flaking bark of old sycamore trees.

When the bole of an old sycamore tree expands the old rigid bark cracks and begins to curl at the edges, while ....

.... a fresh, new layer of bark forms underneath. It might not look very attractive but these bark flakes, some as large as a slice of toast, take a long time to fall off and while they are still attached harbour a remarkable fauna of small invertebrates underneath. Here's a selection, most of which I've yet to ID.

Millipedes, a hatched moth pupa and some unidentified cocooons 

Lots more millipedes - these were just a few from under two bark scales - if this sample is representative there must have been hundreds sheltering under the bark of this tree

A minute scarlet mite

A rather beautiful little money spider, Gonatium rubens

A huddle of earwigs ....

... that raised their tail forceps in defence when they were suddenly exposed to the light. Male left, female on the right.

A spider that lives in a silken tent under the bark

Lots of slugs in areas where the bark is permanently damp, where rain water trickles down the tree trunk ..

.... together with snails ......

...... and woodlice

Another moth pupa, that looks as though it hatched successfully.


Sycamore sits low in the league table for tree foliage that supports insect biodiversity - a 1961 research paper on the subject found only 15 species, compared with the 284 hosted by oak (click here for details). But a quick look under the flaky bark of old sycamores casts them in a more favourable light, as a sheltered habitat for a host of invertebrates. 

The few examples shown here were just from a height that I could reach - there may well be a different array of species higher up the trunk and the hosted species most probably vary depending on the aspect (sunny & south facing or shaded & north-facing). Moisture must play a role too because there are well defined runnels where rainwater flows down the trunk from the branches and the bark there is always moist and often very wet. All in all, flaking sycamore bark is probably quite a complex habitat, with many interesting interactions between species that inhabit it.