Black-and-gold Flat Millipede

• It manufactures hydrogen cyanide: it mixes two compounds stored separately in lateral glands and releases a gas smelling of bitter almonds, enough to kill an insect shut in with it.
• Several species in the group, all toxic, share the same colour pattern in a case of Müllerian mimicry: predators learn a single signal and avoid them all.
• Its sixty or so legs are not for running but for pushing: millipedes are burrowers that force their way through compacted leaf litter.
• It manufactures cyanide. When disturbed, it secretes from lateral pores a mixture that releases hydrogen cyanide, in a quantity sufficient to kill a mouse shut in a container with it.
• It does not store it ready-made, which would be suicidal: it keeps a precursor, mandelonitrile, in a chamber separate from the enzyme that breaks it down, and only when the two are secreted together is the cyanide released. It is a two-component system, like an epoxy glue.
• Its smell gives the process away: it smells strongly of bitter almonds, which is the characteristic smell of cyanide.
• Its yellow and black colours are aposematic, and several species in the group form Müllerian mimicry rings, sharing the same warning pattern.
• It is harmless if left unhandled, but it is wise to wash your hands after touching one, because the secretion irritates the skin and stains.
• It is an important decomposer of the leaf litter of the Appalachian forests.

Skeleton type

Invertebrate - chitin exoskeleton (myriapod)

Habitat and environment

Leaf litter and decaying wood of the deciduous forests of eastern North America

Sources consulted: Marek et al., trabajos sobre mimetismo y defensa química en Xystodesmidae; Universidad de Virginia Tech; Eisner, For Love of Insects

The pins mark the parks where its presence is documented.