Warner Corner - September 2008

Yellow, slimy slugs!
Julie Grecian, Assistant Director

A few weeks ago, I came inside from teaching a one-hour summer camp for two and three year olds and their parents. Our class was Treetop Tots and we were on a search for birds, squirrels, acorns and nests up in the treetops. To our delight, we instead became fascinated with all the slugs we found along the forest trail. Bright yellow and oozing "slimy, sticky stuff," as one child exclaimed, was the highlight of the hike. I could tell the parents weren't as excited about touching them but they fascinated me. As I was leaving that day, I again noticed an abundance of slugs along the sidewalks, in the potted plants, and even on the railings. What was making them appear so suddenly? Where had they been hiding? What exactly is that "slimy, sticky stuff" they leave behind as they move along ever so slowly in this fast-paced world? I decided to do some research to find out.

Best described as snails without shells, they are a type of mollusk with soft-bodies, no backbones, and are hermaphrodites, with both male and female reproductive systems. One of the most interesting body parts for me is their eye stalks. Known as optical tentacles, they are used as sensory tentacles to find food, tasting and poking about in their environment.

Slugs can be as small as 1/4 inch and larger than two inches. One of the most fascinating characteristics of slugs is the silvery slime trail they secrete and leave behind as they move around. Adapting to being damp and crawling around in the dirt all day, the slime is actually secreted to make sure things don't stick to it! Be gentle when touching them as when slugs are disturbed or handled roughly, the slime becomes even more sticky.

Slugs love to eat plants from young seedlings to mature plants, as well as decaying matter. Eating by rasping with specialized mouthparts, they feed mostly at night. Since they can stretch their bodies far beyond their normal length, they can squeeze through tiny openings to get at food. Wondering who wants to eat these slimy creatures? Many different types of animals eat slugs, including ground beetles, salamanders, garter snakes, ducks, turtles, and toads.

Living up to a year, they can survive during the winter months as eggs in protected sites underground. The eggs hatch during spring or early summer and depending on the weather, they may lay eggs throughout the summer. While you have a better chance of seeing them at night when it is cool and damp, you may also see them during the day in cool and shaded areas.

With over 40 species of slugs in the U.S., Minnesota is home to the yellowish, dark-splotched banana slugs (Ariolimax columbianus) and many European non-native slugs. Some websites report that banana slugs are usually only found in the forest while the other species are the ones that typically cause much anguish to gardeners and plant lovers.

Depending on the website you research, slugs can be described as very damaging pests, voracious consumers, and even the most despised creatures in nature. Slugs can be very damaging in moist, shady gardens. They like to feed on the leaves of many plants, as well as ripening fruits and vegetables. Despite the damage they can cause, I love finding them in the forest—a bright yellow spot among the green and brown colors.

Next time you notice the weather is cool and moist, look down where you walk—you might spot one of these amazing creatures and get to watch them in action!