Explanation of Names
Greek diplous (διπλους)- "double" + pous (πους)- "foot, leg"
Numbers
Approximately 7,000 species have been described from a global fauna that is estimated, based on known degrees of endemism, to contain around 80,000 species, and we know very little about the fauna of China, which may really be immense.
Fifty-two families and ca. 914 described species inhabit the US and Canada, but the Parajulidae (order Julida), the largest family on the continent, is essentially unstudied, and some 200 undiscovered species are anticipated in this taxon alone.
Size
3-270+ mm worldwide; the longest North American species (Paeromopus paniculus) grows to 160 mm in length
Identification
Millipedes have three body segments in front with one pair of legs each, and the rest with legs have two pairs of legs each (47 to 375 pairs of legs and 25 to 189 body segments, not counting head and tail).
Centipedes have only one pair of legs per segment throughout.
Sexing millipedes:
Males often have missing legs where their
gonopods are located. While many species have the gonopods on the seventh segment, some do not. See an example of what to look for
here.
Habitat
Moist areas such as under rocks, rotting logs, leaf debris.
Food
Most millipedes eat decaying plant material, but a few species occasionally can be carnivorous. Some may also occasionally eat moist, living plants.
Life Cycle
Millipedes hatch from eggs. Millipedes molt as they grow, and with each molt they gain more segments and legs. Millipedes can be long-lived, sometimes up to seven years.
Remarks
To discourage predators, millipedes coil into a protective spiral, or roll into a defensive ball, and many emit poisonous or foul-smelling substances.
Many millipedes with bright color patterns (see the image below) secrete a compound containing cyanide. Wash your hands after handling them and do not allow children to pick them up.
"Millipedes lack the structures to bite, pinch, or sting, and are harmless to humans, although the defensive secretions burn if they get into the eyes." [Rowland Shelley]
"Millipedes are entirely non-toxic to humans and can be picked up by hand. Some secretions discolor the skin, but this wears away in a few days without lasting effect. Some large, cylindrical, tropical species squirt their defensive secretions up to a half meter (2-3 feet) and can blind chickens and dogs. Their fluids are painful if they get into the eyes, and persons working with tropical millipedes should be suitably cautious." [Rowland Shelley]
Millipedes can be further classified into orders: Polyxenida, Spirostreptida, Spirobolida, Callipodida, Chordeumatida, Platydesmida, Polyzoniida, Polydesmida, Julida, Glomerida, Sphaerotheriida, Glomeridesmida, Arthropleuridea, and Euphoberiida.
See Also
Sometimes confused with
centipedes, which have only one pair of legs per body segment, the last legs extend backwards behind the body, the animals can run fast, and can bite.
Print References
Shelley, Rowland M. 1999. CENTIPEDES AND MILLIPEDES with emphasis on North American fauna. The Kansas School Naturalist. 45:3. 16 pp. Emporia State University, Kansas.
A Golden Guide - Spiders and Their Kin.
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