Rhagor - Opening our national collections

Ghost Slug Update, Spring 2010

[image: Ghost slug update 2010]

[image: Ghost slug update 2010]

[image: Ghost slug update 2010]

[image: Ghost slug update - Spring 2010]

Help us find out more about the mysterious alien "Ghost Slug": Update, Spring 2010

Thanks to all 200 of you who have contributed so far! Since July 2008 we have had reports of sightings from all over the UK (and beyond) showing how far our message has travelled. As requested, many people sent photos or specimens that allowed us to verify the identity of their slugs, or brought them to the Museum here in Cardiff.


A definite pattern has emerged from the verified Ghost Slug records (see map). These are all from south-east Wales, with one from the English border at Hay-on-Wye and one from Knowle, Bristol. Although people in this part of Britain may have been more likely to respond to our appeal, we think this reflects the actual distribution of the species because our other responses came from so far and wide.

The map indicates the slug has already spread quite widely, but only within a small part of the UK. Why is this area so small? Perhaps because it arrived only recently, and is still on the move. The earliest verified sighting is from Brecon in 2004 ]. The slugs cannot have crawled all these miles by themselves, so must have been spread by man, probably in soil or compost. Alternatively, the area in which the slug has been found may simply be the region in which it best survives and breeds. The south-east Wales — Bristol region has a broadly similar climate and soils, which are evidently to its liking.

The verified Ghost Slug records have all been submitted to the Conchological Society of Great Britain and Ireland who record the distribution of all British and Irish molluscs.

Habitat and seasons

All the verified Ghost Slug records are from gardens, or urban areas adjacent to gardens. These are habitats in which many other alien species are found. Of course, they are also the places in which people are most likely to notice slugs. Live Ghost Slugs have been found at nearly all times of year (see graph). There is a peak in the warmer months that could reflect increased activity or numbers of slugs, but this is also when people spend more time in their gardens. It seems this species does not mind the cold! The latest observation proves that at least some Ghost Slugs have survived our coldest winter for 30 years; an adult was found in Cardiff at the beginning of March 2010.

Another pale slug to look out for

Many people confused the Ghost Slug with the Field Slug Deroceras reticulatum, included in our ID guide. This is a pale, herbivorous species common in gardens and lawns. A smaller number of people sent in pale specimens of the Worm Slug (Boettgerilla pallens). The name "Worm Slug" comes from the body shape; unlike the Ghost Slug, this species does not feed on earthworms. Like Field Slugs, Worm Slugs have eye spots and a breathing hole nearer the middle of the body. The breathing hole is in the saddle-shaped part of the slug called the mantle (see photo). The Ghost Slug is quite different; it has both the mantle and the breathing hole at the tail end of the body, and has no eye spots. The Worm Slug is thought to come from the Caucasus (the same part of the world as the Ghost Slug), and has spread very rapidly in Britain since the 1970s.

Are we still interested in Ghost Slug sightings?

Yes! We want to monitor any further spread of this species especially if found elsewhere in the UK or Europe. Contact details are on the ID guide. Remember that sightings must be verified with a specimen or photograph if they are to count.

Thanks once again to all those who have taken part.

Article Date: 6 June 2010


yvonne on 4 October 2013, 19:51

Hi I have seen one in my yard not sure which one it is I live in Gateshead in the north east.

Julian Woodman on 4 January 2013, 13:41

Hi Ben (I geuss)
Rich facey sent me this update - I am still looking but nothing yet.

Just wondered if it might be worth labelling the images in the update - I realise it says in the text that the photo is of Boettgerilla, i was initially confused.

I was pleased to have recently id'd Tandonia budapestensis and T. sowerbyi from my garden in Pentyrch. Also lots of Hygromia cinctella as well which i may have brought with me from Canton.

all the best

Graham frost on 8 August 2012, 14:39

I live in edmonton alberta and i found a whole bunch if ghost slugs in my backyard. I found it odd their airway was so far back compaired to other slugs. If this is rare or not im not sure. Not much data on alberta slugs.

Jenny Gledhill on 25 March 2012, 21:19

I have found between 4-6 Ghost Slugs on my allotment in North London, mainly where I had spread commercially bought compost/cow manure last autumn.

I knew I had dug up something unusual this spring when one of the slugs had an earthworm securely in what looked to be its mouth. My neighbour had to tug hard to free the red earth worm.

Emma on 24 May 2011, 09:54

Forgot to leave you my email address when i posted last night: maddy_louise@yahoo.co.uk

Emma on 24 May 2011, 09:17

I think i have ghost slugs in my garden!!! Have had them for 3 years now ......several garden centres have failed to identify them....i live in East Sussex

Nigel Houlden on 21 September 2010, 09:42

I think I#ve just seen a ghost slug in my garden in Wrexham North Wales.

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