Millipedes are slow-crawling arthropods belonging to the class Diplopoda. Approximately 10,000 species exist worldwide, though only about 60 occur in Canada. Also called “thousand-leggers,” millipedes earn recognition for their long, rounded bodies and scores of legs. Despite having a name that means “1,000-footed” in Latin, millipedes actually have fewer than 100 legs in most cases. Though not harmful, millipedes can secrete a foul-smelling toxin if agitated.
Appearance / Identification
What Do Millipedes Look Like?
Millipedes have hard, cord-like bodies made up of multiple segments; each segment has a pair of legs. Because of their many pairs of closely arranged legs, millipedes tend to move slowly, with their legs pushing in a wave-like pattern. When alarmed, millipedes coil up in a tight spiral shape. Size varies greatly by species, with the smallest millipedes measuring about 2 cm in length. While tropical millipedes may measure as long as 30 cm, most Canadian millipede species only reach a length of about 8 cm. Most millipedes are entirely black, though some species may appear dark brown or reddish. They have short but visible antennae made up of 7 segments.
Often confused with centipedes, millipedes have two pair of legs on each body segment, whereas centipedes have one pair per segment. Millipedes are also more rounded in shape. Additionally the millipede travels much slower than the rapid-moving centipede.
Millipedes are ground-dwelling arthropods that live outdoors and thrive in dark habitats with plenty of moisture. Known to feed on decaying plant matter, millipedes often reside directly within sources of food, like piles of leaf litter or rotting logs. The arthropods also commonly burrow in areas where soil stays moist, like under rocks or piles of mulch.
Mostly detritivorous, millipedes feed on decomposing organic matter, such as leaf litter and dead wood. Millipedes play an important role in the natural cycles by helping to break down plant matter after it has undergone microbial decomposition. In the absence of decaying material, millipedes may feed on the delicate roots of seedlings or ripening fruit lying on the ground.
Life Cycle / Reproduction
Female millipedes deposit sticky clusters of hundreds of eggs in cavities found in soil and other decaying organic substances. Young millipedes hatch from the eggs with three pairs of legs and then experience numerous molting stages. After each molt, the number of segments and legs increases. Typically, millipedes experience seven to 10 molts before reaching adulthood, which may take a course of about two to five years depending on the species. After reaching adulthood, millipedes tend to live for another three or four years.
Problems Caused by Millipedes
As minor garden pests, millipedes living outdoors may damage sprouting seeds, seedlings, and ripening fruit. While not destructive inside the home, millipedes create a minor nuisance by being an unwelcome sight. Although the arthropods die shortly after coming inside, their hard exoskeletons remain intact for a while after. Handling certain millipedes may result in irritation of the skin known as millipede burn. An effect of the toxic chemicals millipedes secrete when alarmed, millipede burn symptoms include brown staining of the skin, blistering, and itching or burning of the skin.
Detection /Signs of Infestation
Millipedes sometimes take residence in the basements of homes. Needing ample moisture for survival, the arthropods usually die of dehydration a day or two after entering. Homeowners typically notice infestations by finding the hard, shell-like remnants of dead millipedes.
Homeowners rarely need to take significant control measures against millipedes, as invasions tend to comprise only a handful of the creatures. To deter millipedes from entering the house, homeowners should keep the residence clean and free of clutter, especially in basement areas. Eliminating potential hiding places also discourages millipedes from taking up residence in the home. Reducing the amount of moisture in the basement makes the home less attractive to the pests, as well. Seal exterior cracks and crevices around the home to prevent millipedes and other pests from entering, and contact a pest control professional when the levels of infestations become too high or overwhelming to handle alone.
To better understand what millipedes look like, review the images below.