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Spotted garden slug

Limax maximus

What do they look like?

Length

15.24 cm (high)
(6 in)

Spotted garden slugs can attain at least 6 inches in length. They vary in color from yellowish-gray to brown with black spots on the mantle near the head and black stripes extending along the rest of the body. The tail area is wrinkled. There is a pneumostome or breathing pore on the back part of the mantle that this slug uses to breathe.

Sexual dimorphism:

sexes alike.

Where in the world do they live?

This slug is an introduced species in North America and other temperate regions of the world.

Biogeographic Regions:

nearctic (introduced).

What kind of habitat do they need?

Spotted garden slugs are found in moist places in fields, woods, and gardens. They inhabit damp ground under wood, rocks, vegetation, and other shaded areas.

These animals are found in the following types of habitat:

temperate; terrestrial.

Terrestrial Biomes:

forest.

How do they grow?

Eggs are approximately 1/4 inch in diameter, and when first laid, they are colorless and transparent. Gradually, the eggs become cloudy, resembling small pearls. Development is direct whereby larval stages occur within the egg, and eventually, tiny slugs emerge from the eggs. Limax becomes sexually mature in two years.

How do they reproduce?

Number of offspring

130 (high)

A pair of slugs will hang by a mucus string from a branch while they mate.

Egg size in late summer is smaller than egg size in autumn. In addition, clutch sizes are larger in summer than in autumn. In the autumn, a clutch size may be 50 to 130 eggs. Spotted garden slugs may exhibit aggression toward other slugs or snails when shelter sites for breeding are scarce.

Key reproductive features:

sexual; oviparous.

How long do they live?

This slug may live up to three years.

How do they behave?

Spotted slugs have photoreceptors that are used to detect light levels in its environment. They will become active when the ground surface temperature ranges from 44.2 to 65.7 degrees Fahrenheit.

These slugs are capable of learning about their environment. They will respond to odors encountered. When a bad smell is evident in the presence of food, a slug will learn to avoid the food. However, if it detects a bad smell, and then some time later, a bad smell is detected in the presence of food, the slug will not avoid the food.

These slugs will absorb water by through their muscular foot. They will engage in huddling behavior with each other to conserve body water and avoid dehydration. This occurs most often during the winter. To avoid too much water in the body, these slugs will give off excess water. They may also estivate, or become dormant, during dry periods.

A spotted garden slug is able to compact its body to half its length while creeping along the ground. It secretes a slime trail that help it glide more easily.

Key behaviors:

nocturnal; motile.

What do they eat?

Spotted garden slugs will eat fungi, decaying organic matter, and plants.

Primary Diet:

mycophage; detritivore.

Plant Foods:

leaves; lichens.

Other Foods:

fungus; detritus.

What eats them and how do they avoid being eaten?

When irritated, spotted garden slugs will secrete a colorless mucus. A slug may lift its tail and vibrate it back and forth as a means of scaring a potential predator. It may clamp its mantle to the ground to protect its head. To scare away predators, it may even squirt blood through its breathing hole!

What roles do they have in the ecosystem?

This slug may help cycle nutrients in soil via its feeding activities.

They may be an intermediate host for trematodes and nematode worms.

Certain kinds of protozoans may be parasitic in them.

Key ways these animals impact their ecosystem:

biodegradation.

Do they cause problems?

This slug has been known to damage gardens. It may be an intermediate host for some trematode and nematode worms which can harm our pets.

Ways that these animals might be a problem for humans:

crop pest; causes or carries domestic animal disease.

How do they interact with us?

This slug may contribute to regeneration of soil because of its eating habits.

 
University of Michigan Museum of Zoology National Science Foundation

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BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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