Black slug
The black slug, belonging to the family Arionidae, is a large, shell-less mollusk found in regions including Europe, Australia, and North America. Growing up to six inches in length, its color can vary from brick red to dark brown to pale orange. This nocturnal creature primarily thrives in moist environments, where it feeds on a diverse diet that includes rotting plant matter, soft fruits, and living organisms, making it an omnivore. Black slugs have a long, narrow body with four tentacles, two of which serve as eyes to detect light, while their mantle houses internal organs and a breathing hole.
As hermaphrodites, black slugs possess both male and female reproductive organs and mate by exchanging sperm through spermatophores. They typically lay eggs in loose soil, which hatch into miniature versions of the adults after four to six weeks. Black slugs have a lifespan of approximately two years and are not considered a threatened species. As they play a role in their ecosystems by decomposing organic matter, they contribute to soil health and nutrient cycling.
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Black slug
The black slug is a slippery, slimy creature which is closely related to snails, but unlike snails does not have a shell. The black slug spends its life feeding on and living in moist, or wet, vegetation. The black slug can be found in Europe, Australia, and North America.
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Order: Stylommatophora
Family: Arionidae
Genus: Arion
Species: Ater
Growing to a maximum length of about four to six inches (10 to 15 centimeters), the black slug is a large, slimy creature. In spite of its name, the black slug may range in color from brick red to dark brown to pale orange.
The black slug has a long, narrow body. On its head are four tentacles. The two longer tentacles hold the black slug's eyes. All of these tentacles help the black slug sense its environment and find food. Scientists suspect that the eyes of the black slug serve only to distinguish between light and dark for the purposes of knowing when it is day and night.
Behind the black slug's head is its mantle. This part of its body is slightly raised with a grainy texture. All of the black slug's internal organs are held within its mantle. Along one side of the black slug's mantle is its breathing hole. Air is taken into the black slug's lung cavity and expelled through this hole.
Below the mantle is the black slug's sole. This is the largest portion of the black slug's body. This part serves as a foot, sliding along the ground helping the black slug to inch its way forward.
The black slug was originally only found throughout Europe and parts of western Asia, but today this slimy mollusk has also been introduced into Australia, New Zealand, and North America. The black slug spends most of its time crawling along the ground while it feeds on rotting plant matter and soft, decaying animal matter. This creature also feeds on a varied diet of living organisms, leaves, seedlings, and soft fruit. This diet makes the black slug an omnivore, or plant- and meat-eating animal. As a nocturnal creature, the black slug generally only comes out of its hiding place during the night. Sometimes it also comes out during the day, but only after a rain shower. During cold and dry weather, the black slug typically burrows in the soil where it is moist and warm.
The black slug reaches its sexual maturity at the end of its first year. At this point, the black slug mates. Black slugs mate in spring and early summer. As a hermaphrodite, or creature which has both male and female sexual organs, the black slug mates both to release sperm and to have its own eggs fertilized. The black slug transfers its sperm to its mate in a small package called a spermatophore. The eggs are fertilized inside the black slug's body and then laid. The black slug lays its eggs in loose soil. The eggs stay in the soil for four to six weeks before hatching. Typically, black slug eggs hatch in the spring as miniatures of their parents. Black slugs can lay up to 150 eggs every one to three weeks.
The black slug has a life span of up to two years. They are not a threatened species.
Bibliography
“Black Slug.” Encyclopedia of the Puget Sound, 2024, www.eopugetsound.org/content/black-slug. Accessed 8 May 2024.
"Species of the Week: Black Slug.” Irish Wildlife Trust, 2020, iwt.ie/species-of-the-week-black-slug. Accessed 8 May 2024.