Pill bugs, often called roly-polies or woodlice, are terrestrial crustaceans, related more closely to shrimp and crabs than to insects. They are characterized by their segmented bodies and their ability to roll into a protective ball when disturbed. Understanding their diet is key to appreciating their beneficial function within soil-based environments.
The Primary Diet of Pill Bugs (Detritus)
The core of the pill bug’s diet is decaying organic matter, scientifically termed detritus. This makes them primary detritivores, consuming the remnants of dead plants and animals. Their preferred food is moist, decomposed plant material, such as fallen leaves, rotting wood, and compost. They are found in dark, damp environments like under logs or in leaf litter, where this food source is abundant.
Pill bugs are equipped to handle tough components of dead plants, utilizing symbiotic microorganisms to help break down resistant materials like cellulose. They selectively consume the softer parts of dead leaves and wood, which are often coated in bacteria and fungi, aiding digestion. They also engage in coprophagy, consuming their own feces to re-ingest nutrients and microbes. This recycling maximizes the extraction of copper and other essential elements.
Supplemental Food Sources in the Wild
While detritus forms the bulk of their diet, pill bugs are opportunistic feeders that consume a variety of other items. They frequently feed on fungi, algae, and moss found growing in their moist habitats. These items provide different nutrient profiles and are important when primary food sources become scarce.
They may occasionally nibble on soft fruits, such as fallen berries, or damaged root vegetables. Pill bugs rarely consume healthy, living plant tissue, preferring materials that are already dead or decaying. If the environment is dry or detritus is insufficient, they may turn to tender plant seedlings or roots to survive. They have also been observed scavenging on decomposing animal flesh or the shed skins of other invertebrates.
Pill Bugs’ Role as Decomposers
The foraging of pill bugs drives nutrient cycling within ecosystems. By consuming detritus, they physically break down large pieces of organic matter, increasing the surface area for microbial decomposition. This action is important for returning nitrogen, phosphorus, and potassium back into the soil.
As they move through the soil and leaf litter, they help mix and aerate the top layers, improving soil structure. Their digestive process releases nutrients readily available for plant uptake, effectively fertilizing the environment. Pill bugs also ingest and sequester heavy metals such as copper, lead, and zinc, helping to detoxify certain soils.
What to Feed Pill Bugs Kept as Pets
For those keeping pill bugs (isopods) as pets, their captive diet should closely mirror what they find in the wild. The foundation of their enclosure should be a constant supply of leaf litter, such as dead oak or maple leaves, which provides both food and habitat. This leaf litter should be supplemented with fresh vegetable scraps, which are sources of moisture and nutrients.
To ensure a balanced diet, several supplemental items should be provided:
- Safe supplemental foods include pieces of carrot, potato, apple, and lettuce.
- Protein for healthy growth and reproduction can be offered via small amounts of commercial fish flakes or dried pet food.
- Calcium, important for forming their hard exoskeleton, is supplied by placing cuttlebone, oyster shell, or powdered eggshells into the enclosure.