On a field trip to the Featherfin Wildlife Management Area last week, the Biology of Arthropods class collected a wide diversity of arachnid and myriapod species, but the most striking were two specimens, a male and a female, of the giant millipede Narceus americanus. This species ranges from southern Canada to Florida, and recent work on its DNA has shown that there are actually a half-dozen genetically isolated populations involved, whose distribution has waxed and waned over the past million years with the comings and goings of continental glaciers.

Narceus americanus, about as thick as a pencil and 5 inches long, is the largest North American millipede.

As shown by the picture below, N. americanus is often attacked by the glow-worm Phengodes. The glow-worm runs the millipede down, flips it over and with a bite severs the ventral nerve cord to disable the potent chemical defenses of the millipede.  The paralyzed millipede is then reduced to soup by regurgitated enzymes and sucked up by the glow-worm.

The glow-worm Phenogodes is a specialist on Narceus. See text above for details.