Rolly pollies, also known as pillbugs or woodlice, are common invertebrates often found in gardens and beneath rocks. These small, segmented creatures are not insects; they are terrestrial crustaceans, more closely related to shrimp and lobsters. A distinctive trait of many rolly pollies is their ability to curl into a tight ball when disturbed, a defense mechanism called conglobation that protects their softer undersides.
The Right Environment
Rolly pollies require specific environmental conditions to survive, particularly concerning moisture and shelter. As crustaceans, they breathe through gill-like structures that require constant moisture; dry conditions are fatal. Consequently, they seek out damp, humid places, often found under rocks, decaying logs, leaf litter, mulch, or garden debris.
These invertebrates also need sheltered, dark spaces to hide from predators such as birds, spiders, and centipedes, and to avoid direct sunlight, which would quickly lead to desiccation. Their preferred habitats include soil, compost piles, and areas where moisture is retained, but they cannot survive submerged in water. Rolly pollies prefer moderate temperatures; extreme heat or cold can be fatal. The substrate they live in, such as moist soil or decaying organic matter, is crucial for both moisture retention and providing hiding spots.
What They Eat
Rolly pollies are primarily detritivores, which means their diet consists mainly of decaying organic matter. They play a significant role as decomposers in ecosystems, breaking down dead plant material and returning valuable nutrients to the soil. Their preferred foods include decaying leaves, rotting wood, fungi, and other decomposing vegetation.
While they primarily consume dead material, rolly pollies may occasionally feed on soft fruits, vegetables, or even young, tender plant seedlings, especially if their preferred decaying food sources are scarce. They also have a need for calcium, which is important for maintaining their hard exoskeleton. This calcium is obtained from their diet of decaying plant matter or other mineral sources in their environment. They practice coprophagy, consuming their own feces to reabsorb nutrients like copper.
Their Life Cycle
The rolly polly life cycle involves several distinct stages. Female rolly pollies carry their eggs in a specialized fluid-filled pouch located on their underside, known as a marsupium. This pouch can hold anywhere from 10 to 200 eggs, providing a protected, moist environment for development. After approximately one to three months, manacae hatch from these eggs.
These young manacae remain in the mother’s marsupium for a few days to several weeks after hatching before venturing out. As rolly pollies grow, they periodically shed their rigid exoskeleton in a process called molting. Unlike many other arthropods, they molt in two halves, first shedding the rear portion of their shell, and then, a few days later, the front portion. This two-stage molting helps reduce their vulnerability to predators. Rolly pollies live for about two to three years, though some individuals can survive up to five years under optimal conditions.