November 2, 2015
Snail slime has many names-snail mucin, snail secretion filtrate, or just plain snail mucus. But is it going to save your skin? Snail slime has hit the beauty market in spectacular fashion, enhancing face creams, moisturizers, gel masks, and skin repair serums. South Korean cosmetics companies have been at the forefront of this trend with claims that these snail slime products reduce wrinkles, repair damaged skin, improve acne scars, and lighten dark spots. So, from what magnificent snail comes this “miracle” beauty product? The common garden snail.
Tonymoly Intense Care Snail Hydro-gel Mask with its “creator,” Cornu aspersum. It's scientific name is Cornu aspersum, and if you’ve seen a snail on the sidewalk after a rain, chances are it is this species. It's not only common in Los Angeles, but thrives as an introduced species far beyond its native Europe. Check out the over 650 observations of this species on iNaturalist from Van Nuys to New Zealand. Garden snail slime, as an ingredient in “cosmeceuticals” (a hybrid cosmetic and pharmaceutical product), is collected from live snails, filtered, then added to other ingredients to make various skin products. Some of which show promise in small studies to heal sunburn and accelerate wound repair. In analyses of snail slime, cosmetics researchers discovered that the garden snail has five types of mucus cells, each of which produce a unique mix of chemicals, including one of the darlings of the skin-care industry, glycosaminoglycans, or GAGs. These molecules attract water and are therefore often used in moisturizers to plump up skin. When referring to Cornu aspersum, snail slime product labels use creative names including “black snail” or “Chilean earth snail”, which presumably sounds more exotic than “common garden snail.” One product hails the species’ “ever-resilient” qualities and notes that it is “lauded for its ability to survive harsh environments.” In more scientific sounding contexts, it is referred to as “Cryptomphalus aspersa”, a mostly un-used alternative name, or “Helix Aspersa Müller,” also incorrect as Helix is now considered an out-of-date genus name and aspersa, the species name, should be written in lowercase in italics. The story of the naming and re-naming of this species by biologists since the late 1700s deserves its own discussion, which you can find some of here. One of the major players in that story is Otto Friedrich Müller, a Danish naturalist who first described this species in 1774. This is the very same “Müller” sometimes tacked onto the end of the species name, by convention. I would like to think that Otto would be amused to know that 240 years after he described this species, its slime is “beautifying” faces across the globe. Many thanks to Su Oh, Natural History Museum of Los Angeles County, for bringing the beauty product at the top back from Korea.
September 25, 2015
There is a new citizen science project in town and we need your help to document the snails and slugs that call Los Angeles home. SLIME (Snails and Slugs Living in Metropolitan Environments) kicked off earlier this year, and we are already making some interesting discoveries about life in L.A.'s slow lane.
White Italian snails on a sprinkler at the White Point Nature Center, San Pedro, Los Angeles County. Notice the variation in color and pattern. Photo by Austin Hendy. There are about a dozen common land snails in Los Angeles County. If you’ve hiked within the Palos Verdes peninsula, or up to the Baldwin Hills Scenic overlook you’ve probably seen two of the most common snails in urban Southern California. Like most Angelenos, they thrive in a Mediterranean climate and, in fact, ARE from a Mediterranean climate. The white Italian snail (Theba pisana) and milk snail (Otala lactea), hail from Southern Europe and reproduce abundantly in our neighborhoods, their adopted home. They are often found clustered on the same plant stem, sprinkler, sign, or fence, and in numbers from the dozens to hundreds. Despite this presence, and close proximity to people in Los Angeles parks and along hiking trails, they are often confused for each other or misidentified as other species. Here's why. Both are highly variable in color and in pattern. The next time you seen a bunch of them, take a close look. In white Italian snails, shell color can range from white to tan with varying degrees of banding, zigzags, and stripes of variable thickness. Likewise, the milk snail’s shell can range from almost totally white to heavily banded with brown and tan stripes, which can be solid or stippled. And, to add to the confusion of the casual snail-watcher, these species sometimes overlap in habitat, as in the gardens of the White Point Nature Center in San Pedro.
Milk snail on a twig at the White Point Nature Center, San Pedro, Los Angeles County. So how do you tell the difference? The white Italian snail (Theba pisana) is the smaller of the two species and at maturity is about the size of a dime. As an adult, its umbilicus, or the center of the underside of the shell, is partially covered by the lip of the shell. The milk snail (Otala lactea) is the larger of the two species and about the size of a quarter at maturity. As an adult its umbilicus and part of the underside of the shell is glossy and brown in color.
Easily distinguing a milk snail (left) from a white Italian snail (right) by examining the underside, or umbilical view of the shell. Such confusion is not limited to sizable snails you’d find hiking, but makes distinguishing two tiny Los Angeles snails tricky as well. If you look under rocks, among leaf litter, or in the soil of potted plants, you might find two more snail doppelgangers: the orchid snail (Zonitoides arboreus) and the glass snail (Oxychilus sp.). They share the same two-toned gray-colored bodies, and flattened amber-colored shell, but can be distinguished by size and subtle differences in the shell.
Glass snail (top) and orchid snail, tiny snails with subtle differences. When in doubt, which is most of the time even for seasoned snail observers, the best way to photograph a snail for identification is to take images of the shell from three different angles; the top (apical view), the side (apertural view), and the bottom (umbilical view).
The 3-view approach to photographing milk snails apical (top), apertural (middle), and umbilical (bottom) views. So next time you find a snail (or slug for that matter) take pictures and send them into the SLIME project. You can submit them directly to iNaturalist, e-mail them to firstname.lastname@example.org, or tag them #natureinLA on social media. Either way, you will be able to put your new-found snail identification skills to the test, and I might get to help with the tricky taxonomy of terrestrial molluscs.
March 23, 2012
We've discovered a snail never before found in L.A.! A few weeks ago, I was wandering through the North Campus and happened upon a tiny gastropod snailing along the Living Wall! Most snails don't catch my attention as they are usually of the common garden variety, aka Brown Garden snails, Helix aspersa. This particular specimen caught my eye, because unlike the Brown Garden snail, this snail was much smaller and flatter (the shell is only 6.9 mm wide). I grabbed the snail, placed it in a vial and took it to our snail expert, Lindsey Groves.
Brown Garden snail, Helix aspersa
Southern Flatcoil snails photographed in Cathedral City (Image courtesy of Patrick LaFollette, Museum Research Associate) Lindsey is the Museum's Malacology Collections Manager and when I showed him the snail, he got pretty excited. Although some people may find this strange, I did not. In fact, I was excited too. What I did find strange was that Lindsey already had another specimen of the exact same species sitting under his microscope at that very moment!
Malacology Collections Manager, Lindsey Groves It turns out that the snail I found is a Southern Flatcoil snail, Polygyra cereolus. According to Lindsey, this species of snail ranges from southern Florida to South Carolina and across much of the Gulf coastal states to Texas, as well as several areas of northeast Mexico. Over the past few of decades, it has become common in other locations such as Wisconsin, Hawaii, and even a number of countries in the Middle East including Qatar, Saudi Arabia, and the United Arab Emirates! These range extensions are attributable to accidental introductions through importation of sod and/or ornamental landscape plants. The specimen that Lindsey was examining under his microscope was recently collected in the Laguna Hills area of Orange County. He is currently working on documentation of this new county record and will also document the snail found on the North Campus, which is now preserved in the Museum's Malacology collection. The snail has also been discovered a bit further afield in Cathedral City, Riverside County.
Top view of Southern Flatcoil snail. Another in a long list of introduced terrestrial mollusc species in our area, 20 to be exact, it is reported that the Southern Flatcoil snail feeds on clover and alfalfa. As such, they have in some instances been reported as agricultural pests, but will likely feed on many other types of vegetation found in parks and gardens. In Florida, they have been observed assembling in large numbers on sides of buildings and walls without apparent regard to sun exposure, which is very unlike many snails. In one building at the University of North Florida, an aggregation of thousands of individuals were found coating the building surface! According to one of Lindsey's colleagues in Florida, "they are like a weed."
Side view of snail. Apparently the characteristic apertural 'tooth' for this genus must have broken off when it was collected.
June 13, 2017
April 19, 2017