[ HARPAPHE HAYDENIANA ]
Many residents of the Northern California coast are familiar with the ubiquitous yellow-spotted millipede (nicknamed the black princess). Roaming a wide variety of forested habitats on wet days, these many-legged creatures reach densities of up to 20 to 90 individuals per square meter, and in some studies, they comprise more than 30% of the total invertebrate biomass. Such a common and openly visible organism would be ideal for the forest’s many predators except millipedes protect themselves when threatened with a squirt of hydrogen cyanide. If you pick one up you’ll immediately notice this bitter, almond-like smell on your fingers, and you’ll probably put it back down rather quickly. It’s not poisonous to large animals, but for smaller critters it can be toxic.
Yellow-spotted millipedes play an important role because they consume more than a third of all conifer needles falling to the forest floor and convert them into frass, which decomposes readily and releases large amounts of nitrogen byproducts into the forest ecosystem.
This black millipede with yellow spots along its margins is several inches long and has 31 pairs of legs on 20 body segments. Keen observers recognize males because one leg on the seventh segment is reduced and is used to transfer sperm to the female.