Don't Kill Woodlice (Pill Bugs): Nature's Recyclers
Woodlice Visit Your Home in Autumn
Don't be too quick to get rid of woodlice. You may not want them in your home, but they play a valuable role in your garden. They have a key role in nature's cycle of decomposition and regrowth.
Their normal home is outdoors amongst garden leaf litter or in dark, damp crevices, or under stones. As the weather gets cooler, they move into your house looking for somewhere warm to help them survive the winter months. They prefer places where they can live undisturbed in moist conditions. To prevent their stay becoming permanent you need to change these favorable conditions and proof your home against a future roly-poly visit.
If you find them in the garden, please don't kill them. Woodlice are harmless to humans and they are a food source for other animals. The bodies of pill-bugs provide a good source of calcium for some spiders, birds and frogs.
Woodlouse in the Garden
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.
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 be the result.
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.
Where Do Woodlice Live?
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.
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.
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. I bought a to carry out the experiment for myself. Each chamber is differentiated so that woodlice can make a choice between moist or dry, dark or light environments. choice chamber kit
The video shows how this experiment demonstrates that woodlice prefer dark and 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
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. Woodlice help to recycle dead plant and vegetable matter.
Woodlice occasionally come into houses from gardens, but they are unable to survive for long indoors unless they find a damp place to shelter. So remove any damp or rotting wood in your home and you are unlikely to find woodlice there. Those you do encounter can be retuned unharmed to their natural environment, your back-yard.
Would Salt Deter Slaters?
Slaters is another local name (Australian) for woodlice and pill-bugs. Using salt to deter roly-polys is an old folk remedy for infestations. The idea is that as woodlice crawl across a line of salt, their bodies become dehydrated and they die. I have tried this remedy, but not found it very effective. The advantage of salt is that it is a safer alternative to using poisonous chemicals if you have pets or children in your household.
The Garbage Collectors of The Environment
"Woodlice feed on dead organic matter: fallen leaves, soft bark, dead roots, mushrooms and potatoes that have been left in the ground, as well as cadavers. In fact they will even eat the bodies of other, dead woodlice.
Acting as ‘garbage collectors’ to the soil, they serve an important purpose. Without them, plants would have less access to nutrients in spring, slowing down their growth. And we would have to go to the bother of getting rid of all the dead leaves from our garden ourselves."
Matty P. Berg, The Centre for Soil Ecology.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.