Harpaphe haydeniana
From ize
Harpaphe haydeniana is a Polydesmoid millipede. It is commonly called the Clown Millipede, Almond-scented Millipede, or Cyanide Millipede. It is common on the forest floor along the Pacific coast of North America.
| Taxonomy | |
|---|---|
| Kingdom: Animalia | |
| Phylum: Arthropoda | |
| Subphylum: Myriapoda | |
| Class: Diplopoda | |
| Order: Polydesmida | |
| Family: Xystodesmidae | |
| Genus: Harpaphe | |
| Species: H. haydeniana (Wood, 1864) |
Contents |
Identification
This conspicuous millipede has aposematic coloration, being black with light yellow patches along the dorsal edge of its body. There are a total of approximately 20 body segments with two pairs of legs with each segment. The first and last segments are legless. Females have 31 leg pairs whereas males have 30 leg pairs, the seventh segment being modified for formation of gonopods and sperm transfer. When mature they can reach a size of 5 cm.[1]
Geographic Distribution
Central California to coastal southeast Alaska. Common in mid to low elevation forests on the Pacific Northwest coastal region.
Habitat
Moist forests, under leaf litter, in soil, and under large moist logs
Life History
Reproduction occurs in spring. Several hundred small eggs are laid in loose clusters in soil or leaf debris. Developing individuals are much paler than adults. Segments are added at each molting period, and they get increasingly darker with yellow patches becoming more prominent. They reach reproductive maturity when they reach 4 to 5 cm long, having approximately 20 segments. Life expectancy is about 2-3 years. [2]
Ecology
Detritivorous. Harpaphe haydeniana is an important part of the forest ecosystem here in the Pacific Northwest with its role in regulation of plant litter decomposition and nutrient cycling. Their major role in decomposition is specifically in the modification in the physical and chemical character of the litter. Both the adult and immature individuals feed on organic matter. Growth occurs more rapidly in leaf litter than contains more plant carbon and nitrogen, or an increased microbial biomass. Abundance generally depends on the quantity and quality of litterfall.[3]
Behavior
When threatened, H. haydeniana secretes hydrogen cyanide. This has a similar scent to almonds, hence why it is sometimes referred to as the almond scented millipede. The dose of cyanide that is emitted from the sides of its body is toxic to shrews, predatory beetles, and other insects. The hydrogen cyanide is therefore a powerful defense mechanism and they are generally avoided by potential predators. The ground beetle Promecognathus laevissimus is known to be a specialized predator. When handled may also stain skin.[4]
Footnotes
- ↑ Hopkin, S. P. & H. Read, 1992. The Biology of Millipedes. Oxford University Press, New York.
- ↑ Hopkin, S. P. & H. Read, 1992. The Biology of Millipedes. Oxford University Press, New York.
- ↑ Baumeister, N., 2002. Nutritional Ecology of Millipedes in Pacific Northwest Conifer Forests. Oregon State University, Oregon.
- ↑ Haggard, P. & J., 2006. Insects of the Pacific Northwest. Timber Press, Oregon.
