TRAIL CHATTER - THE THUG LIFE OF A SLUG

 

Spotted this slug on Section 6 of the Ouachita Trail

The Thug Life of a Slug    

        The moment we saw the slug on the trail, I thought about when I was a child when my grannie would let us put table salt on the slugs surrounding her beautiful flower beds. The table salt would dissolve them before they reached the flowers to cause their damage. It sounds cruel to me now that we tortured them with table salt. Their fate was table salt versus pesticides. I remember them being a lot bigger than the one we saw on the trail. 

 

          The thug life of these tough-skinned, menacing terrestrial secretes a film of mucus for protection. These little thugs are agriculture pests. Their crime against foliage is devastating. They can destroy foliage faster than plants can grow, thus killing even large plants. They act in their own self-interest and make decisions to commit their crimes without hesitation. Slugs are vital to the natural cycle, as they aid in rapid decomposition and return needed nutrients to the soil.

 

They are similar to snails, however, slugs evolve without a shell, scientists believe, due to lack of calcium in the environment and high dampness or humidity levels. Slugs' bodies are made up mostly of water. They must generate protective mucus to survive. Many species are most active just after rain because of the moist ground. In drier conditions, they are great at playing hide and seek in damp places such as under tree bark, fallen logs, rocks and leaves to help retain body moisture. Only between 5 and 10 percent of slugs are above ground. The remaining 90 to 95 percent of the slug population is below ground.

          Slugs produce two types of mucus: one is thin and watery, and the other thick and sticky. Slugs also produce thick mucus that coats the whole body. The mucus secreted helps prevent the slug from slipping down vertical surfaces. The "slime trail" a slug leaves behind has some secondary effects: other slugs coming across a slime trail can recognize the slime trail as produced by one of the same species, which is useful in finding a mate. Body mucus provides some protection against predators, as it can make the slug hard to pick up and hold by a bird's beak or the mucus itself can be distasteful. Slug slime is gross. But for the slug, it is crucial. It allows them to glide the foot muscle along the ground. Slugs are gastropods. Which means stomach foot. The foot, which is the flat bottom side of the slug, is a powerful muscle. This muscle contracts in rhythmic waves while the slug secretes slime at the same time. This allows the slug to glide across the slime as its foot contracts. A slug’s slime is as unique as human fingerprints. Slime contains special fibers that make it extra sticky and helps to ensure slugs can make vertical climbs without sliding backward.

    Slugs have both male and female genitalia. If there are no suitable mates, slugs can impregnate themselves. When two slugs’ mate, both get pregnant as they exchange sperm. Slugs partially encircle one another. The male parts of the slugs join together in a kind of corkscrew to exchange sperm. However, they frequently get stuck like this. Then one slug will chew off the penis of its partner or even its own to get “unstuck.” The victim, however, can survive with just female genitalia and can continue to breed. A few days later the slugs lay eggs in a hole in the ground, or beneath the cover of an object such as a fallen log. A single slug lays up to one hundred eggs several times each year. And bearing in mind that, mostly, when slugs mate, both get pregnant, you can see how quickly 1000s of slugs can appear. A single slug can accumulate a staggering 90,000 descendants during its lifetime. Slug eggs are those tiny pearly white balls you find in the soil as you dig. Small, round, delicate, and easy to squish. But they are remarkably resilient. Slug eggs can lay dormant for years and only begin to hatch when conditions are optimal. So, even if you are sure, you are totally on top of controlling slugs naturally, there can, in fact, be thousands of eggs in your soil, just waiting for the perfect conditions.

          Most species of slugs feed on organic materials, including leaves from living plants, lichens, and mushrooms. Some slugs are predators and eat other slugs, earthworms, and snails.

     

        Slugs eat only fungi at specific stages of development. They can eat whole mushrooms. When we were hiking Section 6 and 7, I spotted these three mushrooms above and something had been nibbling on them. After my research, it is possible it was a slug. It would have been a cool photo if I could have caught one having a mushroom for lunch.  Slugs have 27,000 teeth. They use this ridiculous number of teeth to rasp away at their food leaving ragged holes in leaves. Who would think that a slug has more teeth than a shark? And, just like sharks, slugs regularly lose and replace teeth.

If you accidentally squish one under your boot, you will see that they exude green-yellowish blood. This is due to the molecule, hemocyanin, that transports oxygen in slugs.

 Slugs are preyed upon by birds, reptiles, mammals, amphibians, and fish. Fish that feed on slugs include the brown trout. Amphibians such as frogs and toads have long been regarded as important predators of slugs. Reptiles that feed on slugs include snakes and lizards. Many birds’ prey upon slugs as well. When attacked, slugs can contract their body, making themselves harder and more still and round. The slippery mucus they produce makes slugs more difficult for predators to grasp. The unpleasant taste of the mucus is a deterrent. Slugs can produce a highly sticky and elastic mucus which can trap predators in the secretion. Some slug species can self-amputate (autotomy) a portion of their tail to help the slug escape from a predator.

 

Some slug species hibernate underground during the winter in temperate climates, but in other species, the adults die in the autumn. Slugs are prone to attack during the summer and are more of a thug, when availability of resources is reduced. During the winter, their aggressive responses are substituted by a friendly behavior. 

 

          Slugs can cause meningitis in humans, resulting in significant brain damage. The disease is not due to direct contact with the slug, but to consuming it orally voluntarily or accidentally. While, rare, there are reported cases of humans eating slugs and contracting serious disease. One tragic case involved a young man in Australia who eventually died after being dared to eat a slug from a garden. Accidental consumption may occur if someone eats poorly washed produce.

 

While on my hikes, I like to get as curious as a child. We are never too old to learn new things. At 60 years old, I have discovered there is still a lot of mystery in nature that I want to explore. Honestly, I never thought it would be the thug life of a slug.