Centipedes are often mistaken for insects due to their segmented bodies and numerous legs. However, they belong to a distinct group of arthropods. Their unique biology reveals fascinating adaptations and behaviors. They are predatory organisms.
Understanding Their Classification
Centipedes are not insects. They are classified within the phylum Arthropoda, which includes insects, arachnids, and crustaceans. More specifically, centipedes belong to the subphylum Myriapoda, a group characterized by many body segments and numerous legs. The name “Myriapoda” means “many feet.” Within Myriapoda, centipedes constitute the class Chilopoda.
Insects belong to the class Insecta and possess three distinct body segments (head, thorax, and abdomen) and typically six legs. Myriapods, including centipedes, retain a largely uniform trunk with paired segmental appendages, distinguishing them from insects.
Defining Characteristics
Centipedes have elongated, flattened bodies divided into multiple segments. Each segment, except for the last two, bears a single pair of legs. While their name suggests “hundred feet,” the actual number of leg pairs varies widely among species, ranging from 15 to 191. This segmented structure allows for flexibility, enabling them to navigate confined spaces.
A distinctive feature is the presence of forcipules, pincer-like appendages located just behind the head. These modified first pairs of legs contain venom glands. Centipedes use these venomous claws to capture prey. Their heads also feature long, segmented antennae that serve as sensory organs, compensating for their limited vision.
Habitat and Behavior
Centipedes primarily inhabit damp, dark, and secluded environments, such as under rocks, logs, leaf litter, or within soil. Their preference for moist microhabitats stems from their lack of a waxy cuticle, causing them to quickly lose water in dry conditions. This leads them to avoid direct sunlight and makes them nocturnal.
As active predators, centipedes control populations of other invertebrates. They hunt small creatures, including insects, spiders, and other arthropods, using speed and venom to overpower prey. While generally shy and inclined to flee from humans, centipedes can deliver a defensive bite if provoked. Though painful, often compared to a bee sting, their venom is rarely life-threatening to humans.
Centipedes vs. Millipedes
Centipedes are frequently confused with millipedes, despite both belonging to the subphylum Myriapoda. One primary difference lies in their leg arrangement: centipedes have one pair of legs per body segment, whereas millipedes have two pairs of legs on most segments. This difference is often noticeable in their movement, with centipedes being faster and more agile compared to the slower-moving millipedes.
Their body shapes also differ, with centipedes having a flattened, elongated body, while millipedes typically exhibit a more rounded or cylindrical form. Diet provides another distinction: centipedes are carnivores, hunting other small animals. In contrast, millipedes are primarily detritivores, feeding on decaying plant matter and playing a role in decomposition. Their defense mechanisms also vary; centipedes use venomous forcipules for defense, while millipedes often coil into a spiral or release noxious secretions when threatened.