Arionidae

All images on this website have been taken in Leicestershire and Rutland by NatureSpot members. We welcome new contributions - just register and use the Submit Records form to post your photos. Click on any image below to visit the species page. The RED / AMBER / GREEN dots indicate how easy it is to identify the species - see our Identification Difficulty page for more information. A coloured rating followed by an exclamation mark denotes that different ID difficulties apply to either males and females or to the larvae - see the species page for more detail.

Slugs, Snails & Bivalves

Slugs, snails and bivalves are molluscs - a group that also includes Octopus, Squid and Cuttlefish, and one of the most successful invertebrate groups to have evolved. Most mollusc species are found in oceans but a few have adapted to live in freshwater and some can live on dry land. These terrestrial species move by secreting mucus to lubricate their path but this results in the loss of water and all are vulnerable to dessication. To avoid this they either live in damp habitats or retreat into their shells during dryer weather.

Around 100 snail and bivalve species and 25 slug species have been recorded in Leicestershire and Rutland (VC55). Others are likely to be found as some species are expanding their range and may appear in our area.

If you need ID help, a great site is the Facebook - Slugs & Snails where you can submit photos and an expert will usually respond.

The ID resources described below are for molluscs in general. More specific help can be found in each of sections below.

Click on the headings below to expand/contract the text.

Slugs

Terrestrial slugs evolved from terrestrial snails. Without a shell, slugs are are less dependent on a calcium diet and are more agile - squeezing into tight spaces. However they are more vulnerable to dessication. The slime that slugs produce helps to keep them hydrated when moving around but they need to find a moist retreat at other times.

Click on the headings below to expand/contract the text.

Here are a few tips of the slug features it helps to photograph. Also add a note to your record about size - this is often crucial information.

  • a dorsal or oblique view of the whole animal - showing the keel if it has one and ideally with the head/tentacles extended
  • a side view from the right side showing the breathing pore
  • the sole (some have a central dark stripe or dark edges)
  • whilst not easily photographed, the colour of the mucus can be important so stroke the slug and examine the slime on your finger!

Arionidae