Terrestrial isopods, commonly known as woodlice, pill bugs, or roly-polies, are small terrestrial crustaceans that have successfully adapted to life on land. As one of the few land-dwelling members of the class Crustacea, these organisms play a significant part in nearly every terrestrial ecosystem. They are classified as detritivores, meaning their diet is entirely focused on consuming non-living organic material. This specialized feeding habit establishes them as nature’s recyclers, facilitating the breakdown and return of nutrients to the soil.
The Core Diet: Decomposers’ Feast
The diet of isopods in their natural habitat centers almost entirely on detritus, which is the decaying organic matter found on a forest floor. Their primary food source is leaf litter, with a preference for certain types of hardwood leaves, such as oak and beech, over softwoods. This preference is partly due to the chemical composition of the leaves, as the isopods consume the leaf material itself along with the nutrients it harbors.
As they fragment and ingest the detritus, they are not only consuming the plant matter but also the complex community of microorganisms attached to it. The fungi and bacteria engaged in the decomposition process are a rich source of nutrients for the isopods. They digest the initial decomposers, making the nutritional value of a decaying leaf significantly higher than that of a fresh one. This diet also extends to soft and hard rotting wood, which they consume for both the cellulose structure and the microbial life breaking it down.
Essential Nutritional Supplements
While decaying plant matter forms the bulk of their intake, isopods require specific supplementary nutrients for healthy growth and reproduction. The most significant of these requirements is calcium, which is necessary for the formation and maintenance of their hard exoskeleton. As crustaceans, isopods must periodically shed their outer shell, a process called molting, and access to sufficient calcium is required for successful re-calcification of the new shell. A lack of this mineral can lead to failed molts, which is often fatal for the organism.
Protein is the other major nutrient isopods seek out beyond their detritus diet. This macronutrient is important for juveniles experiencing rapid growth and for adult females preparing for breeding cycles. In the wild, they fulfill this need by consuming small amounts of animal matter, such as dead insects or their own shed exoskeletons, a practice known as exuviae consumption. This behavior ensures they acquire the concentrated amino acids necessary to support their biological functions.
Feeding Terrestrial Isopods in Captivity
For those keeping isopods in controlled environments, providing a balanced diet requires constant access to their primary food source, along with supplemental items. Boiled hardwood leaf litter, such as oak or magnolia leaves, should be kept in abundance, as this mimics their natural intake and keeps the microorganisms flourishing. The leaves should be replaced regularly as the colony consumes and fragments them.
Calcium Sources
To ensure proper calcium intake, keepers often provide cuttlebone, which is a readily available source of calcium carbonate. This can be placed directly on the substrate for the isopods to graze on at will. Alternatively, plain calcium powder can be lightly dusted onto their supplemental food items a few times a week.
Protein Supplements
Protein supplements are necessary to encourage robust growth and breeding success within the colony. High-protein items like fish flakes, small amounts of dried shrimp, or commercially prepared isopod foods can be offered one to three times per week. These concentrated meals are consumed quickly, providing the necessary boost for development.
Fruits and Vegetables
Beyond protein and calcium, a variety of fresh vegetables and fruits can be offered to diversify their diet and provide moisture. Safe choices include:
- Slices of carrot
- Zucchini
- Sweet potato
- Small pieces of apple
These items should be monitored closely, and any uneaten portions must be removed within 24 to 48 hours to prevent the growth of harmful mold. High-citrus fruits and overly processed human foods should be avoided, as they can be detrimental to the isopod’s system.