Millipedes, common in gardens and damp environments, often cause concern due to their appearance. Despite their multi-legged look, millipedes do not bite or sting in the traditional sense. These arthropods are detritivores, primarily feeding on decaying plant matter and playing a role in ecosystem decomposition. They are considered harmless to humans, lacking venomous fangs or stingers for defense.
Millipede Defense Mechanisms
When threatened, millipedes employ defensive strategies, primarily relying on chemical secretions and physical posture. They possess specialized glands along their bodies, called ozopores, which release defensive fluids. These secretions can contain a variety of irritating chemicals, such as benzoquinones, phenols, cresols, and in some species, hydrogen cyanide derivatives, with exact composition varying by species.
Beyond chemical defenses, millipedes also utilize a physical defense mechanism. When disturbed, many species coil tightly into a spiral or ball. This protective posture shields their vulnerable underbellies and delicate legs within their hardened exoskeleton. This combination of chemical deterrence and physical protection helps them ward off potential predators.
Effects of Millipede Secretions on Humans
While millipedes do not bite, contact with their defensive secretions can cause mild irritation in humans. The fluids may lead to temporary skin discoloration, often yellow or brown. Symptoms can include itching, burning, and localized skin irritation. In some instances, contact may result in blistering or a rash.
If millipede secretions come into contact with the eyes, they can cause immediate pain, tearing, redness, and inflammation. While rare, severe eye exposure can lead to more significant issues, though permanent blindness is not well-substantiated. If contact occurs, wash the affected skin thoroughly with soap and water. For eye exposure, flush the eyes with plenty of water for at least 20 minutes and seek medical attention if symptoms persist or are severe.
Distinguishing Millipedes from Centipedes
Millipedes are often confused with centipedes, but distinct differences exist between these multi-legged arthropods. Centipedes typically have one pair of legs per body segment, whereas millipedes possess two pairs of legs on most of their body segments. This difference in leg arrangement gives millipedes a more rounded, cylindrical body shape, while centipedes tend to have flatter bodies.
Behaviorally, centipedes are fast-moving predators that use venomous fangs, called forcipules, to capture and inject venom into their prey. Millipedes, conversely, are slow-moving detritivores. While a centipede bite can be painful to humans, it is generally not life-threatening, though allergic reactions are possible. Understanding these distinctions is important for identifying these common arthropods.