Slug Walk

That would be slowly.... Indeed I can walk frustratingly very slowly and when leading our local Woodland Wanders the participants don't get much exercise.

Via my BSBI membership I was invited on a walk last Saturday afternoon, but not a botanical one, it was to be led by Chris du Feu who is a slug expert, although also well known for writing the BTO Nest Box Guide (23). The site was to be The Field in Dunkeld which is a community owned and run food growing site.

The invitation included bringing some slugs along to be examined, but when I ventured out the evening before, in ideal, warm and wet conditions all that could be found was one Green Cellar Slug, and a Tree Slug, both climbing up the house walls. However, some subsequent investigations, the next morning, under our row of plant pots did reveal a couple of tiny Arion spp, and into a pot they went.

Arion spp are tricky, both large and small, and the hand lens was required to determine these. One turned out to be Arion hortensis which I'd not recorded previously, so that was a bonus. The other was either A. hortensis or A. distinctus but was unclear, demonstrating just how hard to determine these can be.

Arion hortensis.

Chris patiently explained how confusing many of these slugs are and gave us advice on identification, as well as a bit of history as to how they were first found and how they spread across the UK. 

We found a good number of species between us including three Worm Slugs, I'd seen just one of these previously which I found in our Orkney garden. 

Boettgerilla pallens Worm Slug, an almost mythical creature! Certainly my favourite slug. Apparently first found in the UK in 1974, when several were found at one extended site. My Orkney garden record is the most northerly in the UK, just pipping Chris's on Shapinsay.

 The Worm Slug I found on Saturday was a bit of fluke as it got scooped into my sample pot along with organic matter as I caught a Bembidion sp, a ground beetle.

Bembidion lampros, at 3.45mm a small one. Note that the 7th elytral stria is absent. I have seen this previously, but a long time ago.

I did record a few "new for me" species on Saturday, most exciting was the ground beetle Anchomenus dorsalis, of which there were two. This is a very attractive species although my "in the pot" image doesn't show it off to its best.

Anchomenus dorsalis

This is a common species across much of the UK but much less so in this part of Scotland, the dot on the map will be visible!

The other slug which caught the eye on Saturday was Tandonia budapestensis, not one of Chris's favourites! But an interesting beastie nonetheless.

Tandonia budapestensis, Budapest Slug.

I'd never come across the Garlic Snail previously, but one was in the pot of finds. The smell of this species is very, very strong and unmistakable. One of the few species that is best identified by smell and may only be confused with various plants of the Allium genus. Visually this glass snail is very similar to others, and snails are very difficult to identify on the whole.

Garlic Snail Oxychilus alliarius

There were various things found that could not be identified to species including a sawfly larva (but I will investigate that further) and  an Epistrophe sp hoverfly larva (thanks NG).

Sawfly larva (maybe found on Oak), so far undetermined.

Epistrophe sp larva

The female agamic gall formed by the hymenopteran Cynips quercus was found on an Oak.

Cynips quercus f agamic

Several Toads and one Palmate Newt were larger, although not necessarily faster moving, creatures found.

Bufo bufo

Lissotriton helveticus Palmate Newt. I should have checked its throat, but forgot to, over confident perhaps, but I think this is the correct ID.

And I have to finish with a slug really. Deroceras reticulatum is a common species across the UK, although Deroceras invadens appears to be displacing it. D. reticulatum has a "Milk of Magnesia" (a really terrible medicine, I can still recall it as being awful, from my childhood) slime trail, most obvious if you let it move across semi-translucent plastic, like a yoghurt pot.

Deroceras reticulatum

Many thanks to all the participants for a very enjoyable afternoon and especially to Liz for inviting me and Chris for sharing his knowledge and enthusiasm.