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With all the wet weather we've had lately, Mary Alice has been busy pulling weeds in her flower gardens. One day last week she yelled for me to come and look at a huge slug.
Then, I heard her say, "Ugh, there are two of them." Later, Mary Alice asked me whether slugs and snails do any good.
I answered that they must do some good or God would not have created then. My answer was not good enough, so I was off to do some research.
Snails and slugs are classified in a general group of invertebrate animals known as mollusks. This name means soft-bodied. Beside snails and slugs, the group includes the octopus and squid.
The modern English word snail goes back to the Old English word snaegel, which is based on an Indo-European word, meaning to creep.
Slugs and snails are opportunistic feeders, eating whatever is available. Slugs eat all types of vegetation, from roots to shoots, which makes them more destructive than snails. But slugs can also eat small invertebrates, keeping them from overpopulating a garden.
The presence of a small number of slugs isn't necessarily a bad thing.
Unlike slugs, snails are primarily decomposers that feed on dead leaves and flowers, speeding up the recycling of plant nutrients. Their feces fertilize the soil much more quickly than bacteria breaks down plant material. Earthworms decompose plant matter at about the same rate as snails do and are far less detrimental in the garden.
While it is not their primary food, snails will eat bug eggs when there is little other food available. They will also feed on the eggs of slugs and other snails, allowing them to act as a natural pest control in a balanced ecosystem. However, they will eat the eggs of beneficial insects as well as those of pests.
When slugs and snails hide underground during the heat of summer, they create small burrows that can aerate the soil. This can be beneficial both to your garden as well as to your compost pile, since air is necessary for decomposition.
They form part of the food chain for birds, frogs, toads, snakes and small mammals, such as chipmunks, field mice, shrews and moles. Have you ever found a snail shell with a hole chewed in it? If you have, it was the work of one of our small mammals. A lot of shells can be found with holes chewed in them, but not many snail shells are found with the snail inside.
After a snail dies, the decomposition of its shell adds calcium to the soil. However, since most soil usually contains a suitable amount of calcium, the small amount of additional calcium makes little difference to the soil. Of course, slugs carry no shells on their backs.
The two main groups of snails are land snails and marine snails. Land snails are generally vegetarians. The land snail is hermaphroditic, with each individual having both male and female glands; however, this does not mean that snails and slugs do not need to mate to reproduce. Late summer is the mating season for most snails and slugs. The courtship consists of rubbing and touching.
The female pore is located on the head, which is indeed an unusual place. When one snail is fertilized, the roles are switched, and the second slug will be fertilized. Several weeks later, the slug or snail will dig a three-inch hole in the ground, where the eggs will be laid. It could take a whole day to prepare the hole, since the foot is used to do the digging.
The general gastropod body consists of a mantle, a fleshy tissue surrounding the remainder of the body that secretes the material of the shell; a head with eye stalks and feelers; a mouth with a rasping organ known as a radula and a fleshy projection called a foot.
Snails and slugs need constant supplies of moisture to continue to be active or even survive. Since we've had a lot of rain this summer, they have been very active. If the weather becomes too dry, the snails' activity ceases and they retire into their shells, where they will live in suspended animation until moisture returns. However, if there is too much water, the snails and slugs will drown. Snails and slugs are largely active at night, and on a cloudy morning following a rainy night, they will remain active until the sun becomes too hot.
Snails and slugs secrete a fluid that is ejected out in front of them, oiling their path to make movement easier and quicker. This slime comes out of its body to lubricate sliding and to protect its underparts. The slime left by slugs and snails remains visable. If a razor blade were placed edge up in a slug's path, the slime would enable it to crawl over unharmed.
On the straightaway a snail can move three inches in one minute. At that rate, a yard would take 12 minutes, and a mile would take 15 days. Perhaps you think that because a slug does not carry a shell it might be faster than a snail, but it is not.
Snails can go a long time without eating or drinking. One snail shell that was believed to be empty was collected to be put in a museum. The shell was pasted on cardboard, labeled, and placed in a display case. Four years later an attendant at the museum noticed that a snail was emerging from the shell. The snail, which was fed a few cabbage leaves, appeared none the worse for its long sleep.
Proverbs 6:6 tells us to shun laziness, "Go to the ant's you sluggard! Consider her ways and be wise." Solomon was trying to tell us in this and proceeding verses that the wise teacher rebukes the slothful person, who characteristically does not begin things; does not complete things and makes excuses for his laziness.
We have many words and sayings attributed to the slug.
A habitually lazy fellow is called a slug; a sluggard is one who is habitually idle. And who among us hasn't felt a little sluggish, especially in the morning? A slug is also a "swig of drink;" a slug is the lead ball fired from a gun; a slug is a solid line of type cast by a composing machine; a slug is a round disk used illegally instead of a coin in a vending machine; If hit in a fight, it is said that you were slugged, and Babe Ruth was baseball's most famous slugger.
I hope I answered Mary Alice's question.
Bill Bower is a retired Pennsylvania Game Commission Wildlife Officer. Read his blog and listen to his podcasts on the outdoors at www.onemaningreen.com.