Should You Get Rid of Woodlice (Pill Bugs)?

Updated on April 8, 2018
Beth Eaglescliffe profile image

Friends say I have "green-fingers" and the garden certainly seems to respond to my efforts. I enjoy observing wildlife and being outdoors.

Woodlouse (roly-poly or pill bug) uncurling.
Woodlouse (roly-poly or pill bug) uncurling. | Source

Please Think Twice Before Getting Rid of Woodlice

Don’t be too hasty in getting rid of woodlice. To have them in your home may be one step too far, but in the garden they have a valuable role as part of a natural eco-cycle of decomposition and regrowth.

If you find them in the garden, please don't try to eradicate them; your garden benefits from their presence. Woodlice play a crucial role in soil ecosystems and they are harmless to humans.. The bodies of pill bugs provide a good source of calcium for animals higher up the food chain that eat them, for example some spiders, birds and frogs. They also have an essential role to play as decomposers in the Nitrogen cycle as shown in the diagram below.

The Nitrogen cycle showing the role played by "decomposers" like woodlice.
The Nitrogen cycle showing the role played by "decomposers" like woodlice. | Source

Woodlice Visit Your Home in Autumn

You are most likely to notice woodlice in your home in the fall. They normally live out-of-doors amongst garden leaf litter or in dark, damp crevices or under stones. As the weather becomes cooler, they move indoors looking for a warmer place to help them survive through the winter months.

Some human homes are more attractive to them than others. They prefer places where they can live undisturbed in moist conditions and where they can have a reliable food source. If you have an infestation of roly-polies then you are have unwittingly provided these environmental conditions for your visitors. To prevent their stay becoming permanent you will need to eradicate this favorable habitat and proof your home against a further invasion.

Various woodlice (including babies) on leaves and breakfast roll crumbs in a terrarium.
Various woodlice (including babies) on leaves and breakfast roll crumbs in a terrarium. | Source

Woodlice Look Like Tiny Armadillos

The scientific or Latin name for a woodlouse is Armadillidium vulgare. They may be small, but they have an important role to play in helping decompose the cellulose in wood and paper. They also help break down animal feces and turn it into useful manure. Their natural habitat is in leaf litter in woodland and shrub areas.

Some local names for woodlice are roly-polies and pill-bugs. These names relate to their ability to form little balls with their armor plating on the outside, protecting their soft innards. Their tough outer shell or exoskeleton has to be shed regularly to enable a woodlouse to grow and mature. The shedding is done in two stages. First it sloughs the rear half of its armor plating and then two or three days later it loses the front half of its exoskeleton. The shedding is done in stages in order to minimize the vulnerability of the creature during the short period it is without its armor.

Woodlouse in the Garden

Woodlice Provide Early Warning of Damp Problems

Although woodlice do not harm human beings themselves, a heavy infestation inside a building may result in damage to wood, paper and plaster. The picture below shows the kind of damage that can occur as a result of such an infestation.

Roly-polies can be helpful in that they alert you to the fact that there is a source of damp in your home. Woodlice need moisture to survive as they breathe through a kind of gills (like a fish) called a pseudo- trachea. Without any water source they would not have been able to successfully set up home in your building. It is essential to identify and remedy any source of dampness to successfully tackle a woodlice infestation. This should be done in tandem with other measures such as proofing your building to stop re-colonization by more roly-polies.

Woodlice eating rotten wood.
Woodlice eating rotten wood. | Source

More Than 3,600 Species

There are more than 3,600 species of woodlice and they are found living all over the world.They are an ancient crustacean species that evolved from a water-based environment to being able to live on land. Different species have adapted to take advantage of a wide variety of habitats and this makes them difficult to eradicate. Their tough outer shell-like skin provides an effective barrier against most variations in temperature and humidity. However, the one thing they are unable to cope with is complete dryness.

The survival and reproduction of pill-bugs has been helped by their ability to eat a wide and varied diet. They are omnivores. Woodlice have a digestive system that allows them to eat things that would poison other species. They thrive on eating animal feces, molds, decomposing food scraps and cellulose.

Local Nicknames for Woodlice


Armadillo bug



Chuggy pig

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Fertile Females

Woodlice have the ability to increase in number quickly. In some species the female lays eggs three times a year with approximately fifty eggs laid each time. The common Garden Woodlouse species, found inside UK homes, lays one clutch of 150 eggs a year. The female woodlouse retains the eggs in a pouch on her body until they hatch. The hatchlings start life measuring approximately 2 millimeters.

A female woodlouse with offspring in her marsupium.
A female woodlouse with offspring in her marsupium. | Source

The Choice Chamber Experiment

Various experiments have been carried out to determine the type of habitat most favored by woodlice. A simple experiment known as the “choice chamber” can be used to demonstrate the creature’s preferred environment. A container with either two or four compartments is used. Each one is differentiated so that the woodlice can make a choice between moist or dry, dark or light environments.

The video below of a choice chamber experiment demonstrates that woodlice prefer dark, damp conditions.

Woodlice Choice Chamber

Eradication and Proofing

Professional pest control operatives may use chemicals to poison and kill woodlice. However, without removing their habitat and food source, a new generation of woodlice will return to take over the newly vacant territory. In order to achieve permanent eradication it is necessary to maintain dry environmental conditions. In the short term this can be achieved through the use of salt barriers. A half inch border of salt poured across external doorways will cause them to dehydrate as they crawl across it.

In the longer term it is necessary to identify and replace areas of rotten timber. Cellulose in wood is one of their preferred food sources. You will need to fill any cracks or holes around windows and skirting boards with decorator’s caulk to prevent woodlice from finding new hiding places.

You may still want to control pill bugs. If so, try out the organic method shown in the video below. It uses cut halves of potatoes or melons to attract the woodlice. it is a non-toxic method of pest control and so is safe to use if you have pets or children.

Organic Pill Bug Control Using a Potato Trap

Woodlice are not significant plant pests and are useful recyclers of decomposing vegetable matter

They are naturally abundant in a healthy garden

Control is therefore not usually necessary

Woodlice can come into houses from gardens but are unlikely to survive for long indoors unless they can find a damp place to shelter.

— Royal Horticultural Society (RHS)

What Eats Woodlice?

There are many natural predators of woodlice. These include shrews, toads, centipedes, some spiders, ground beetles and parasitic flies.

A healthy garden will have a balance of predators and prey, so there is no need to kill any woodlice outdoors yourself.

Indoors, remove any sources of damp and rotting wood and you should rarely encounter any woodlice. Those you do find can be retuned unharmed to their natural environment, your back-yard.


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  • profile image

    Paula 21 months ago

    Amazing what you can find out.. I moved to a bungalow with plenty of grounds. I agree with the damp as I've got outta house which is damp and I have lots of little visitors lol. I really don't mind them but with my grandson starting to crawl I don't think its a good thing with woodlice. I use salt aswell and can Hoover up three times a day when they dry out. I don't want to do this but have to think of my grandson first.

  • IzzyM profile image

    IzzyM 2 years ago from UK

    Very interesting article that I found through Google search.

    I've just moved into an Arts & Crafts house but it lay empty for six months before I moved, while getting some alterations done.

    The place is hoaching with woodlice, yet there is no damp, nor rotting timbers according to the survey. They are dying off through lack of water, thankfully. I'm going to do a thorough search tomorrow for cracks or crevices they could be entering by.