What Do Woodlice Look Like? How to Recognize Them at First Glance

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Woodlice are fascinating little creatures that you might come across in your garden or while exploring the great outdoors. Belonging to the family of terrestrial crustaceans, these arthropods are closely related to aquatic crustaceans like crabs, lobsters, and shrimp.

Their unique appearance sets them apart from other insects you might encounter. These tiny creatures are oval-shaped and have a segmented exoskeleton, giving them a distinctive, pill-like appearance. In fact, they are often called pillbugs or roly-polies for their ability to roll into a tight ball when they feel threatened.

As terrestrial crustaceans, woodlice have adapted to life on land, but they still require moisture to survive. Thus, you’ll typically find them under rocks, logs, or leaf litter, where the environment is damp and suitable for their survival. Next time you’re out exploring, keep an eye out for these intriguing little creatures and appreciate their unique characteristics.

Physical Characteristics

Comparison with Other Species

Woodlice are small crustaceans that can be easily recognized by their exoskeleton and segmented, flat bodies. They are usually grey or brown in color, which helps them blend in with their natural habitats like leaf litter, rotting wood, or under rocks. Woodlice play a crucial role in breaking down organic matter in their environments.

When observing these little creatures, you might notice that they have a similar appearance to both spiders and centipedes. However, there are some key differences:

  • Woodlice have a strong exoskeleton, which is segmented into 14 parts, and they are usually found in damp, dark areas.
  • Spiders have two main body parts (the cephalothorax and abdomen) and possess eight legs.
  • Centipedes have elongated, segmented bodies with one pair of legs per body segment and typically have more legs than woodlice or spiders.

To help you better understand the similarities and differences between woodlice, spiders, and centipedes, here’s a comparison table:

Body Segments14 (flat)2Many (elongated)
Legs7 pairs8 legs1 pair/segment
ColorGrey or brownVariesVaries
HabitatDamp, darkVariousVarious

Remember, when you encounter these creatures in your surroundings, they all have their unique characteristics and important roles in their respective ecosystems. By being able to recognize their physical traits, you’ll have a better understanding of the diverse world of small invertebrates.

Life Cycle

Woodlice, also known as roly-polies or pillbugs, have a fascinating life cycle. Let’s explore it in detail.

Eggs: Female woodlice carry their eggs in a special pouch called a marsupium. This pouch is also known as a brood pouch, and it is where the eggs are protected until they hatch.

Hatch and Young: When the eggs are ready, they hatch into small, white, legless young called mancae. At this stage, they are still within the marsupium and continue to develop there for several weeks.

After leaving the marsupium, the mancae look like miniature versions of adult woodlice, but with fewer body segments. As they grow, they go through a series of moults.

Juvenile to Adult: Each moult allows the woodlice to grow larger and develop new body segments. They will moult several times during their lifespan. During this time, they are considered juveniles.

Once they have completed all of their moults, they are considered adults. Adult woodlice are capable of reproducing.

Lifespan: The average lifespan of a woodlouse is around 1-2 years.

Here’s a quick comparison of the life stages:

Life StageFeatures
EggProtected in marsupium
YoungLegless mancae, develop in marsupium
JuvenileMiniature version of adult, go through moults, develop body segments
AdultCapable of reproduction, lifespan 1-2 years

So during their life cycle, woodlice transition from eggs in a protective pouch to legless young, and then through multiple moults, they develop into adults capable of reproducing. Remember, as with all living creatures, variations in lifespan and appearance may exist in different woodlouse species.

Habitat and Distribution

Woodlice inhabit various environments, including gardens, forests, and even homes. They are commonly found in the United Kingdom (UK) and the United States (US). Here, we will discuss their habitat and some noteworthy aspects of their distribution.

Household Incursion

Sometimes, woodlice venture into human dwellings. You may find them in damp and dark areas of your house. For example, these creatures often seek refuge under logs, rocks, and leaf litter. Woodlice prefer to live in moist soil environments because they require moisture to survive.

Although woodlice are commonly found in various habitats such as forests, gardens, and leaf litter, they are not usually seen in tropical and desert areas. In these extreme environments, their preferred living conditions are harder to come by. Nonetheless, in their ideal habitats, woodlice are known to play a vital role in breaking down organic matter and contributing to the overall dynamics of soil ecosystems.

When it comes to managing woodlice in your house, ensuring proper moisture control can help keep these creatures at bay. Remember, woodlice are not harmful to humans, but their presence can be a sign of dampness or moisture issues in your home.

In conclusion, woodlice are adaptable creatures that can be found in various habitats across the US and UK. Their presence in households is usually an indication of excessive moisture, and addressing this issue can prevent them from becoming unwanted guests in your home.


Peculiar Eating Habits

Woodlice are fascinating creatures, often found in dark, damp environments. These little critters stay in cool areas during the day, becoming more active at night. Their eating habits may seem unusual to you, as woodlice are detritivores, meaning they primarily feed on decaying organic materials. Examples of food sources for woodlice include dead plant materials, fungi, and compost. This makes them beneficial organisms in your garden as they help break down and recycle nutrients through the decomposition process.

While woodlice mainly consume decay, they sometimes snack on fruit, leaves, and seedlings as well. Be sure to keep an eye on your plants and take necessary measures to prevent woodlice from feeding on your precious seedlings. Since these creatures prefer cool and moist environments, maintaining a well-draining garden should prevent large congregations of woodlice. For more information on their diet read this article.

Species Specifics

Nicknames Around the World

Woodlice are small, flattened crustaceans that can be found in various environments. They have earned numerous nicknames around the world including pill bug, roly-poly, sow bug, slater, armadillo bug, cheeselog, doodlebug, and potato bug. Some well-known woodlice species include Armadillidium vulgare, Porcellio scaber, and Oniscus asellus.

Armadillidium vulgare, often called the pill woodlouse, is a little different from the rest of its family members. It has the unique ability to roll into a ball, reminiscent of an armadillo, hence another nickname – the armadillo bug.

Porcellio scaber, also known as the common shiny woodlouse, is one of the most widespread species. As the name suggests, its exoskeleton has a shiny appearance.

Finally, Oniscus asellus, or the striped woodlouse, stands out with its distinctive, irregular striped pattern on its back.

Here’s a comparison table of these three species:

SpeciesNicknameUnique FeaturesImage
Armadillidium vulgarePill woodlouse, Armadillo bugRolls into a ballAv
Porcellio scaberCommon shiny woodlouseShiny exoskeletonPs
Oniscus asellusStriped woodlouseStriped patternOa

To help you easily identify these woodlice species, remember the following bullet-point features:

  • Pill woodlouse (Armadillidium vulgare): rolls into a ball, also called armadillo bug
  • Common shiny woodlouse (Porcellio scaber): shiny exoskeleton
  • Striped woodlouse (Oniscus asellus): distinctive striped pattern on its back

Now that you’re familiar with these species and their unique characteristics, you can have a closer look while exploring your environment and appreciate these small, fascinating creatures.

Threats and Conservation

Woodlice are small, terrestrial crustaceans commonly found in moist habitats. They play an essential role in breaking down organic matter, which helps maintain a healthy ecosystem. However, they also face numerous threats in their natural environments. In this section, we will discuss the threats woodlice face and conservation efforts in place to protect them.

Predators and Pests

Woodlice have various predators that include birds, beetles, and toads. These predators naturally help control woodlice populations in the wild. In some cases, woodlice can become pests themselves, particularly when they infest damp areas of homes and gardens. Fortunately, they are not harmful to your health or property, but they can be a nuisance if their numbers increase. To keep them at bay, you can keep your home and surroundings clean and dry, thus ensuring that they don’t thrive and multiply.

Conservation and Wildlife

As part of the wildlife ecosystem, woodlice contribute to nutrient cycling and provide food for numerous predators. Despite not being endangered or threatened, their wellbeing is vital to maintaining natural balance. Efforts to conserve habitats can help protect woodlice populations. By being aware of these small creatures’ importance, the different factors that threaten them, and their role in the ecosystem, you can contribute to their conservation and play a vital role in sustaining biodiversity.

Remember that woodlice are essential for a healthy ecosystem, and maintaining their natural habitats will keep their populations thriving. So, the next time you see these small crustaceans, think about their vital role and do your best to educate others on the importance of conservation and wildlife protection.

The Role of Woodlice in the Ecosystem

Woodlice, our little crustacean friends, have a significant role in maintaining the health of ecosystems. You might not realize it, but they contribute to crucial processes like decomposition and nutrient cycling.

As detritivorous organisms, woodlice feed on materials such as:

  • Leaf litter
  • Decayed wood
  • Fungi
  • Bacteria

This feeding behavior helps break down organic matter, making essential nutrients available for plants to uptake. As they digest and metabolize these materials, woodlice also participate in the dispersal of microbiota by voiding fecal pellets, which further aids in the decomposition process (source).

Woodlice have a significant presence in various habitats. For instance, their density in European woodlands can reach up to 800 individuals/m², ensuring a steady contribution to soil dynamics. They are native to many landscapes globally, adapting well to different environments.

In addition to their direct contributions, woodlice indirectly influence other organisms in the ecosystem. Interestingly, the presence of woodlice has been associated with higher predation success by nursery web spiders. This interaction highlights how woodlice play a part in sustaining food chains in their habitats.

To sum it up, woodlice are humble yet crucial players in maintaining ecological balance. By breaking down organic matter and recycling nutrients back to the ecosystem, these little creatures keep our ecosystems nourished and thriving.


  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

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  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

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2 Comments. Leave new

  • Celso Ferrarini Junior
    February 21, 2020 11:27 am

    There are plenty of there here in São Paulo Brasil.
    They like to go under stones and planters, they usually die when turn upside down over slated floor.

  • Celso Ferrarini Junior
    February 21, 2020 11:27 am

    There are plenty of there here in São Paulo Brasil.
    They like to go under stones and planters, they usually die when turn upside down over slated floor.


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