Millipedes are terrestrial arthropods belonging to the class Diplopoda, distinguished by their elongated, segmented bodies. They are often found concealed in dark, damp environments, using their numerous legs to navigate the forest floor and soil strata. This article details the specific dietary habits of millipedes, explaining what sustains them and how their feeding behavior affects the ecosystems they inhabit.
The Primary Diet of Detritus
The vast majority of millipede species are detritivores, meaning their diet consists almost entirely of decaying organic matter, known as detritus. This material is primarily composed of dead plant tissues, such as fallen leaves, rotting wood, and damp mulch, which they consume in the moist conditions of the forest floor. They do not actively hunt or seek out fresh, living food sources.
Their mouthparts are specifically adapted for this diet, featuring mandibles designed for chewing, gnawing, and scraping soft material. These mandibles work to rasp and ingest the mushy, pre-softened fragments of plant matter, often along with the fungi and bacteria growing on the surface. This continuous grazing on the decomposing layer of the soil profile is the baseline feeding activity for nearly all millipede populations.
Millipedes as Essential Decomposers
The constant consumption of detritus positions millipedes as agents in the process of nutrient cycling within terrestrial ecosystems. By ingesting large volumes of decaying litter, they perform a physical function by fragmenting large pieces of plant material into smaller particles. This mechanical breakdown dramatically increases the surface area of the detritus.
The increased surface area allows bacteria and fungi to more efficiently access and chemically decompose the tough cellulose and lignin fibers. Furthermore, the millipedes’ digestive processes and subsequent excretion transform the organic matter into nutrient-rich fecal pellets that rapidly release compounds back into the soil. This transformation increases the availability of elements like nitrogen and phosphorus, promoting overall soil fertility and health.
When Millipedes Consume Live Plants
While detritus is the staple food source, millipedes can become opportunistic feeders and consume live plant tissue under certain environmental pressures. This shift typically occurs when decaying material becomes scarce, such as during periods of extreme drought or when a population grows excessively large. They may also turn to live plants when forced to migrate from saturated soil following heavy rains.
When this occurs, millipedes generally target the softest, most vulnerable parts of the plant, such as delicate seedlings, tender roots, or juicy fruits lying on the ground, including strawberries or potatoes. They use their chewing mouthparts to scrape and damage these soft tissues, but they rarely attack the tough, woody stems or leaves of mature, healthy plants. This behavior is driven by necessity rather than preference.
How Millipede Feeding Differs from Centipedes
The feeding habits of millipedes contrast with those of their relatives, the centipedes. Millipedes are non-aggressive grazers that utilize their chewing mandibles to process static, decaying plant material. They are herbivores and detritivores, feeding on a stationary food source that does not require capture.
Centipedes, conversely, are active, predatory carnivores whose diet consists of live insects, spiders, and other small invertebrates. They possess specialized, venomous appendages known as maxillipeds, which are modified front legs used to inject venom and subdue their prey. This predatory lifestyle requires a different set of mouthparts and behaviors.