Rolly pollies eat primarily decaying plant material. Dead leaves, rotting wood, fallen fruit, and other decomposing organic matter make up the bulk of their diet in the wild. They’re detritivores, meaning they feed on stuff that’s already breaking down, and they play a surprisingly important role in recycling nutrients back into the soil.
Their Natural Diet in the Wild
In nature, rolly pollies (also called pill bugs) spend most of their time hidden under leaf litter, logs, mulch, and other damp debris on the ground. That’s not just where they live. It’s also where they eat. Decaying leaves are their single most frequent food source, and they’ll also chew through soft, rotting wood, fungi, and other decomposing organic material they encounter on the soil surface.
They don’t just passively nibble, either. Rolly pollies produce their own enzymes capable of breaking down cellulose, the tough structural material in plant cell walls. They also carry specialized bacteria in their gut that help them digest even harder-to-break-down compounds like lignin, the stuff that makes wood rigid. This combination of built-in enzymes and microbial helpers lets them extract nutrition from material that most animals can’t digest at all.
Do They Eat Living Plants?
Rolly pollies strongly prefer dead and decaying material, but they will eat living plants under certain conditions. Seedlings, new roots, lower leaves, and fruits or vegetables resting on damp soil are all fair game. The University of California’s pest management program notes that they occasionally feed on succulent plant parts and young seedlings, especially when those plants are in direct contact with moist ground.
Gardeners who’ve dealt with rolly polly damage often notice a pattern: the problem tends to show up around seedlings surrounded by wood mulch. The mulch creates the damp environment rolly pollies need to thrive and reproduce, putting them in close contact with vulnerable young plants. Stressed seedlings (too cold, too dry, or recently transplanted) seem especially susceptible. Healthy, established plants are rarely bothered.
One practical observation from experienced gardeners is that rolly pollies sometimes target living plants when they’re short on calcium, which they need for their exoskeletons. Scattering crushed eggshells around the garden can reduce the problem by giving them an alternative calcium source.
Their Role as Soil Cleaners
Beyond recycling dead plant material, rolly pollies perform a less obvious job: removing heavy metals from the soil. As they eat leaf litter and other decaying matter, they absorb copper, cadmium, lead, and zinc into their bodies. Their digestive system is the main route for this contamination, since leaf litter is where these metals tend to concentrate.
They’re not completely passive about it, though. Certain species can actually detect leaves with high levels of cadmium sulfate and will avoid eating them. Low concentrations of copper in their diet have been shown to stimulate growth in juveniles, while high concentrations accelerate growth even further. This ability to tolerate and store heavy metals makes them useful indicators of soil contamination in ecological research.
What to Feed Pet Rolly Pollies
If you’re keeping rolly pollies in a terrarium or using them as a cleanup crew in a bioactive enclosure, their diet breaks down into three categories: a base of decaying material, fresh vegetables for variety, and occasional supplements for protein and calcium.
The Staple: Leaf Litter and Wood
Dried leaves and decaying softwood should form the foundation of their diet, just as they would in the wild. Cholla wood is a popular choice among hobbyists because it’s soft enough for them to break down easily. Earthworm castings mixed into the substrate also provide a slow, steady food source they can graze on between feedings.
Fresh Fruits and Vegetables
Rolly pollies enjoy a wide range of fresh produce. Cucumber is consistently one of the most popular options, but they’ll also eat carrots, sweet potato, zucchini, watermelon, and apple. Place small pieces directly on the substrate and remove anything uneaten after a day or two to prevent mold.
Protein Sources
Protein doesn’t need to be a daily thing. A small amount once a week is plenty. Dried fish flakes or pellets work well and are easy to store. Algae disks, freeze-dried minnows, and dried shrimp (with the shell on) are all good whole-animal options that provide protein along with a range of minerals. Brewer’s yeast is another convenient choice, packed with protein and B vitamins. In bioactive vivariums, waste from reptiles or amphibians living in the same enclosure serves as a free, built-in protein source.
Calcium Sources
Calcium is essential for rolly pollies because they need it to maintain their hard exoskeleton. Crushed eggshells are the easiest option. Just crush them up and leave a small pile in the enclosure, refreshing it every few weeks. Cuttlebone, the internal shell of a cuttlefish sold at most pet stores, is another reliable source. If you’re already feeding dried shrimp with the shells intact, that alone may provide enough calcium to keep your colony healthy.
Commercial isopod food blends are also available and combine vegetables, protein, and calcium into a single product. They’re convenient if you want a simple all-in-one option, though they’re not strictly necessary if you’re already offering variety from the categories above.
How Much and How Often
Rolly pollies are grazers, not meal eaters. In a well-set-up enclosure with leaf litter and decaying wood always available, they’ll feed continuously on that base layer. Fresh vegetables can be offered every few days, protein once a week, and calcium kept available at all times. The colony will self-regulate. If food disappears quickly, offer a bit more. If it sits and starts to mold, scale back. A small colony of a dozen or so will eat surprisingly little, while a thriving colony of hundreds can go through a cucumber slice overnight.