Soil centipedes (order Geophilomorpha) are common, elongated predators found in soil ecosystems globally. As generalist carnivores, they are integral to the subterranean food web, influencing populations of smaller invertebrates. They thrive in dark, confined spaces, making them specialized hunters within the leaf litter and mineral soil. Studying their diet and predation methods provides insight into nutrient cycling and pest control in the soil environment.
Defining the Soil Centipede and its Environment
Soil centipedes are distinctive from larger, surface-dwelling relatives due to their thin, worm-like shape and pale coloration, typically yellow to brown. They possess the highest number of body segments among centipedes, with species having 27 to 191 pairs of legs, always in an odd number of pairs. This elongated structure is perfectly suited for their subterranean existence.
They are adapted for burrowing, moving through the substrate by elongating their body forward and then contracting, similar to an earthworm. Most species lack eyes and rely instead on highly sensitive, segmented antennae to navigate the dark environment. These antennae detect tactile and olfactory stimuli, helping them sense humidity changes and locate potential prey deep within the soil layers.
These centipedes require microhabitats that retain moisture, such as beneath stones, in leaf litter, and in the mineral soil, sometimes burrowing up to 70 centimeters deep. Like other centipedes, they lack the waxy cuticle of insects and are susceptible to rapid water loss. Their movement through tunnels and interstitial spaces directly dictates the type and size of prey they encounter.
The Specifics of Their Diet
Soil centipedes are obligate predators and generalist carnivores. Their diet consists primarily of soft-bodied invertebrates found within their soil habitat, which they actively seek out by searching through the leaf litter and mineral soil.
They frequently consume small soil earthworms. Gut content analysis confirms the importance of these worms as a food source. They also prey upon a variety of small arthropods, including insect larvae, mites, springtails (collembolans), and small mollusks such as slugs and snails.
Their feeding habits are opportunistic and influenced by local prey availability. While primarily predators, they may occasionally consume plant material if other food sources are scarce. By preying on numerous small invertebrates, soil centipedes help regulate soil pest populations.
How Soil Centipedes Hunt and Immobilize Prey
The hunting strategy of soil centipedes relies on stealth and chemical sensing. Lacking functional eyes, they use their antennae to detect the movement and chemical signals of potential prey in the dark. Their burrowing ability is an asset, allowing them to corner prey within the narrow confines of soil tunnels and limit escape routes.
The primary tools for immobilizing prey are the forcipules, a specialized, modified first pair of legs located just behind the head. These pincer-like appendages are unique to centipedes and function as venom claws. The forcipules pierce the prey’s body and inject a potent venom containing neurotoxic peptides that quickly paralyze or kill the victim.
Once the prey is subdued, the centipede processes its meal using specialized mouthparts. Soil centipedes have reduced mandibles and maxillae adapted for external digestion. They secrete digestive juices onto the prey, liquefying the tissues before sucking up the resulting nutrient-rich fluid. This external breakdown method is necessary for consuming larger food items within their restrictive, underground habitat.