The yellow spots on black make the Cyanide-producing Millipede (Harpaphe haydeniana) easy to identify.

I’m always on the lookout for the small and interesting while walking in the forests of Vancouver Island. While at Seal Bay Regional Park near Comox, British Columbia this week I came across a large yellow-spotted black millipede crossing the trail.

I’ve seen these Cyanide-producing Millipedes (Harpaphe haydeniana) countless times in the forest and have always been fascinated by them. They are a large, easy to identify millipede due to their size and colour. In addition, when handled they curl into a defensive spiral and give off a strong odor that smells like almonds – this smell is the stuff of Agatha Christie – cyanide!

According to Andrew Moldenke, a Research Associate in Entomology, Department of Entomology, Oregon State University, the odor of roasted almonds is actually hydrogen cyanide gas, a potent metabolic poison. As a result, H. haydeniana has only one predator, the groundbeetle Promecognathus laevissimus. Fortunately, this means that the millipede can perform its duty as a “macroshredder,” breaking up plant material and initiating the process of nutrient recyclying in the soil ecosystem without having to worry about a whole host of predators. In fact, it plays such an important role in the process that it can be considered to be a “keystone” species.

The quote below is attributed to Moldenke (I couldn’t find the original link but part of it is similar to a paper authored by Moldenke called Soil-Dwelling Arthropods: Their Diversity and Functional Roles which was presented at a Pacific Northwest Forest and Rangeland Soil Organism Symposium, 1998)

Throughout Northwest forests, the principal shredder is the cyanide-producing millipede (Harpaphe haydeniana), which has a shining black body and bright orange racing stripes. Since the millipede crushes, filters and then recrushes its dead leaf diet, it increases the availability of nutrients 40,000-fold. After extracting what it needs, the millipede defecates a pellet of partially used nutrients covered with microbial fuel (intestinal mucus). Immediately, a microbial garden grows on the surface and then a soil fungivore comes along and breaks up the pellet, feeds, excretes with its own mucus, and the whole process repeats over and over again until all the nutrients are used up. It is the shredder that is key to the process. The cyanide-producing millipede alone eats 33 to 50 percent of all the dead coniferous and deciduous leaves that come to rest on the forest floor. It is one of the most critical links in the entire soil foodweb.

Andrew Moldenke

The Cyanide-producing Millipede (Harpaphe haydeniana) is a key macroshredder in the Pacific Northwest.

As we celebrate Earth Day around the globe it is important to think about the roles that the smaller, often missed, organisms play in the ecosystems that we all are part of. I know that I’ll look at this beautiful millipede a little differently the next time I see it.

If you’ve enjoyed this post you might want to check out the Circus of the Spineless, hosted this month by Arthropoda, for more invertebrate goodness.

Millipede | Family Julidae, Cylindroiulus sp.?

I love turning over pieces of wood, bark, leaves, boards and rocks and discovering things lurking underneath. I found this millipede under an old rotting board at my mother-in-law’s house up at Miracle Beach. I’m unsure what species it is but have fairly confidently narrowed down the Order to Julida and Family to Julidae. Being no millipede expert, I’m humble enough to accept opinions to the contrary!

Millipede | Family Julidae, Cylindroiulus sp.?

British Columbia has approximately 57 species in Myriapoda (millipedes and centipedes). From a purely visual perspective, this millipede appears to be a Cylindroiulus sp. E-Fauna BC lists two species of Cylindroiulus for the province: C. caeruleocinctus and C. latestriatus so it is possible that this millipede is one of these species. Unfortunately, E -Fauna has no photographs or pages for these two species.

Millipede | Family Julidae, Cylindroiulus sp.?

The name millipede means literally “1000 feet.” While many do have a large number of legs, the name is figurative rather than literal. Most millipedes have less than 400 legs, and generally less than 200. The legs are useful to separate millipedes (Class Diplopoda) from centipedes (Class Chilopoda). Millipedes have two pairs of legs on each segment while centipedes only have one pair of legs per segment. In addition, millipedes have short antennae while centipedes have long antennae.

Millipedes are pretty cool to find and observe. I’ll try to search for a few different species to highlight in upcoming blog posts. They’re fascinating creatures and interesting to watch!

Some interesting websites featuring good information on millipedes and centipedes include:

• Milli-peet
• Myriapoda
• Bug Guide

For more reading about invertebrates of all sorts check out the Circus of the Spineless, this month hosted by Marmorkrebs.