What is the Purpose of a Slug?

Slugs can invade gardens in their hundreds or thousands. Many aren’t sure as to what their exact purpose is in the world apart from eating leaves of vegetables.

Slugs are found in all areas of the world with high humidity. Northern states of the US as well as United Kingdom territories in Europe are some of the places where large populations and large slugs are highly common.

Slugs are both detrimental and beneficial. The purpose of a slug is to eat fresh and decaying vegetation as well as to be food for the ecosystem and carnivorous predators.

These creatures might have both beneficial and detrimental roles. To gardeners, slugs are exclusively seen as a pest. Dog owners see slugs as potential threats to their dogs by carrying and spreading disease-carrying bacteria. Here’s why some people see slugs as detrimental and why slugs might also have a positive role in the ecosystem.

Slugs are mainly detrimental

Slugs are seen as one of the most common garden pests. Since they live for years in the ground and often overwinter in the ground while also multiplying, slugs can be one of the only invasive species with considerable damage in the garden.

Slugs eat vegetables

Slugs eat all types of leaves and this includes the leaves of your garden’s vegetables. Some of these vegetables can be cabbages or cauliflower. Slugs can have a mild impact by eating a small section of a leaf or a considerable impact by eating multiple leaves and even killing vegetables by stunting their growth.

slugs eating plants

Slugs come out at night when the air is humid and when there’s no direct sunlight to dehydrate them. They eat and crawl back to the ground or under large objects that act as shade provides during the day.

Slugs cause economic loss

Slugs are a mild problem in gardens but can be a considerable problem on crops. Unless properly managed or crops are rotated to other areas, slugs re-surface the following year in higher numbers eating vegetables and vegetation to the point they create considerable economic damage.

Slugs can be dealt with by using all types of chemicals. Some growers use deterring techniques while those into organic farming consider using non-impactful solutions such as nematodes in the ground against slugs.

The economic losses caused by slugs are often mitigated with pesticides. However, pesticides are the most harmful to vegetables you grow in the garden and it’s often not seen as the best choice in many situations.

Slugs destroy gardens

Some of the most beautiful gardens are those that are well-kept and watered daily. Unfortunately, these are also the gardens where many slugs are prone to appearing since they love humidity and the abundance of food in these places.

Gardens can be significantly impacted by slugs to the extent that flowers, shrubs, and small trees can suffer from hindered growth. They can even be killed by slugs that feed on all of their leaves.

spanish slugs

Slugs are very good climbers. They can access foliage on trees even when there’s a bit of climbing ahead despite their slow speeds. This means you can find slugs on various tree leaves above the ground as well as those on ground level.

Gardens with low-level shrubs and flowers are the most exposed to slug invasions. Newly-emerged plants and flowers are at risk as they have the softest leaves and fibers slugs can eat. Slugs have microscopic teeth which means they can only eat soft and very soft vegetation. They seek new flowers and shrub leaves to feed on in a garden.

Slugs carry parasites

Slugs are known to carry parasites that can be harmful to humans (if eaten without cooking) or to dogs and other pets when consumed by accident.

Rat lungworms are a type of bacteria carried by slugs. These are some of the most detrimental parasites to human and dog health as they impact the circulatory system. Left untreated, parasite infestations caused by slugs can lead to severe bleeding or the death of dogs. In the case of humans, lungworms can affect the spinal cord and the brain without treatment.

The beneficial roles of slugs

Not everything about slugs is bad. For example, slugs are a minor pollinator as they help spread out seeds around the garden. They can have a beneficial role in pollination but this role is typically minor, especially in relation to the damage slugs create to vegetation.

Slugs are food for some animals

Slugs are high in protein and are seen as a quick meal for chicken or predatory species such as foxes. A typical slug can provide around 100 grams of pure protein for chicken. Some people let chickens free around the garden so they can eat grass, slugs, and bugs.

Slugs eat dead vegetation

One of the major benefits of slugs comes with dead or dying vegetation they eat. Slugs don’t eat only fresh vegetation but they also consume various types of decaying fibers. They commonly feed on dead leaves, decaying fruit, and decaying vegetables in the garden such as tomatoes and pepper.

slugs in soil

Slugs eat rodent feces

Another reason why slugs are beneficial is their diet which sometimes includes rat feces. Slugs are known to pick up parasites from rat feces which means they eat the feces of these mammals. Rats are common in fields as they seek out food such as vegetables and various grains.


Slugs can be both beneficial and detrimental to the ecosystem. They are seen as off-putting and even as major pests in gardens. Slugs can eat their way through a garden, especially through newly-emerged foliage.

Slugs also have benefits, often overlooked by their known pest status. They are also decomposers of dead vegetation as they eat dead foliage which is then turned into compost with their excretions.

The negative impact slugs have on the gardens needs attention before they reproduce at a rapid rate. Gardeners apply multiple preventive methods based on natural solutions and ingredients. While not as effective as pesticides, these anti-slug solutions are the only method of dealing with their detrimental impact in gardens without also impacting vegetation.

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