Pill Woodlouse

Armadillidium vulgare


Woodlice feed on mildew and rotting, plants, and can be very numerous in compost heaps or under rocks in the garden. The Pill Woodlouse is rounded and shiny grey, and when it is disturbed, rolls up into a ball (resembling a small pill) to protect itself. It feeds on dead and decaying matter and is an important nutrient-recycler in the various habitats it lives in. It emerges at night to feed and can be seen climbing trees and wall in search of algae to graze on.

How to identify

The Pill Millipede (Glomeris marginata) looks very similar to the Pill Woodlouse and also curls up into a ball. The best way to tell the two apart is by counting their legs: woodlice have seven pairs of walking legs, whereas Pill Millipedes have around 18 pairs.

Where to find it



When to find it

  • January
  • February
  • March
  • April
  • May
  • June
  • July
  • August
  • September
  • October
  • November
  • December

How can people help

Many of our commonly overlooked woodlice are actually important nutrient-recyclers in the habitats they live in. Minibeasts, such as woodlice, can be encouraged into the garden by the provision of logs, stone piles and compost heaps for them to hide, feed and breed in. In turn, other species will be attracted to the garden, as minibeasts are a food source for many animals, including mammals, birds and amphibians, providing a vital link in the food chain. To find out more about encouraging wildlife into your garden, visit our Wild About Gardens website: a joint initiative with the RHS, there's plenty of facts and tips to get you started.

Species information

Common name
Pill Woodlouse
Latin name
Armadillidium vulgare
Crustacea (e.g. woodlice)
Length: 1.1-1.8cm
Conservation status