December 17, 2015
In November, three citizen scientists reported observations to our @NHMLA SLIME project of a handsome looking slug, known as the garden arion, in three different neighborhoods of Los Angeles. No one had ever recorded these slugs in L.A. before! The garden arion is a smallish slug, measuring between 40- 50 millimeters – a little less than half the length of a ballpoint pen. It has a blue/black body, a bumpy mantle (a cape-like fleshy covering near the head), and an amazingly yellow/orange underside (a.k.a. foot). From this foot it makes yellow slime!
Garden arion slugs include two species found in California, Arion hortensis and Arion distinctus. Both are originally from Europe and have been found as invasive species throughout much of North America, where they are associated with human-planted areas like gardens, parks, and farms. In California, these slugs have been common in greenhouses and nurseries in San Francisco and Oakland as early as the 1940s, and recently have been confirmed as established in Riverside and Santa Barbara counties. Without vigilant citizen scientists, there would be no record of the garden arion from Los Angeles County. Thankfully there ARE vigilant and observant citizen scientists contributing to the SLIME project.
To thoroughly establish the extent of this species in Los Angeles County, we need more help from you! We would like to know the geographic extent of the garden arion throughout Los Angeles AND we would like specimens to add to our collection as vouchers, or representatives of the populations living here.
This is where you can help: if you go slug hunting please take pictures of the garden arion, should you find it, and send us your pictures. You can add them directly to SLIME on iNaturalist, or you can e-mail us your photos to email@example.com. If social media is more your thing, you can tag them #natureinLA. Keep track of exactly when, where, and who found the slugs, and any other details about where you found it (under wood pile, on sprinkler, etc.) would be extremely helpful. For example, is this slug found in the open after it rains or does it prefer to stay under flowerpots or rocks?
Likewise, if you find this slug and want to bring it to the Museum, our ticketing staff will be happy to receive it. Just put your garden arion slug in a plastic container with a piece of damp paper towel and something to eat (lettuce is a favorite). Include a label with your name and the location details of where you found your slug. You’ll be a big part of documenting the presence and range of an introduced and potentially invasive species, one of the primary goals of our urban biodiversity research!
Special thanks to iNaturalist SLIME contributors cedric_lee, silversea_starsong, and mckernink.