Millipedes of the Edge

How many millipede species do you think live in southern Ohio?  I estimated there were at least 50, maybe even 80 species.  I was incorrect.

Millipedes are long and usually slow.  They are mega-legged armored trains!  Blindly feeling their way through the forest, they decompose leaf litter and use chemical warfare for protection. 

North American giant millipede pushing its way across the leaf litter.

Not to be confused with centipedes, millipedes have 2 pairs of legs per body segment (centipedes have 1 pair).  Millipedes do not bite using venom (centipedes do).  Millipedes eat decaying plants (centipedes are carnivorous).  Do not pick up a centipede or you may receive a painful pinch. 

Here you see a centipede showing its 1 pair of legs per segment. The first pair is adapted as pincers with venom. 

Here a millipede shows its rounder body with 2 pairs of legs per segment.  1st pair are simply legs, not pincers.

Earlier this spring, we hosted a millipede workshop taught by Derek Hennen.  Derek has been re-writing The Millipedes and Centipedes of Ohio.  This publication was printed in 1928 through the Ohio Biological Survey.  He has been traveling the state updating records, adding species, and has spent some time collecting in Adams County.  He was the perfect person to teach this class.


Derek Hennen teaching millipedes to Advanced Naturalist Class.

From the preserve's previous collection, and what the class collected in May, we identified 19 species of millipede with Derek's assistance.  He believed this to be a fair representation for this area, and it is possible to find a few more species on the preserve.  I was shocked to learn that this is all the taxa we should have in the area.  It turns out, the Appalachian Mountains are the epicenter of millipede diversity in the country.  The further you travel away from the mountains, the fewer species you will find.  Since we are literally on the edge of the Appalachian uplift, but not in the mountains, we have fair diversity.  The Appalachians, where Derek studies, has had new species discoveries, and house some endemic species living in small areas of the mountains.

Narceus americanus annularis, the North American giant millipede

Abacion sp., a common and very smelly millipede when handled.

Oxidus gracilis, the garden millipede is an exotic that can be found in very large numbers.

Pseudopolydesmus serratus, a fairly common millipede.

Here are the millipedes found on the preserve to date:

Abacion magnum
Andrognathus corticarius
Apheloria virginiensis corrugata,  cherry millipede
Blaniulus guttulatus,  spotted snake millipede
Cambala annulata
Cambala minor
Cleidogona sp.
Conotyla sp.
Euryurus leachii
Nannaria terricola
Narceus americanus annularis, North American giant millipede
Ophyiulus pilosus
Oxidus gracilis, garden/greenhouse millipede
Petaserpes cryptocephalus, slug millipede
Pseudopolydesmus serratus
Ptyoiulus impressus
Scytonotus granulatus, granulated millipede
Striaria sp.
Uroblaniulus canadensis

One of the most fascinating parts of millipede life history is the chemistry involved with their protection.  They are not ferocious creatures, they rely on distasteful and sometimes deadly gas exchange to keep predators at bay.  Researchers have discovered many compounds are produced internally, with more yet to be identified.  Even the sweet smelling cherry millipedes are not as pleasant as they smell.  The odor they emit is cyanide.

The sweet smelling cherry millipede, Apheloria virginiensis corrugata.

Some can even release a chemical, staining your hand when they are handled.

Apparently a Narceus did not want to be handled this day.  It oozed a stain out of many pores that discolored my fingers for a week.  Not painful, just colorful.

Euryrurus leachii doesn't produce a good smell, but does produce enough chemicals to positively glow when exposed to ultraviolet light.  This is perhaps another way of warning predators to stay away.

Euryrurus leachii under normal light.

Euryrurus leachii under UV (ultraviolet) light.  Find these under logs with a black light at night.
Photo by Robyn Wright-Strauss

Mating occurs when a male and female find each other, probably through tracking pheromones.  The sexual organs are found between the 2nd and 8th pair or legs, so when they mate, they end up "chest to chest" facing each other.  Eggs will be laid soon after under debris on the forest floor.

Pseudopolydesmus serratus found mating in September.

Chemical warfare used by millipedes, to protect themselves is not fool proof.  One creature adapted to feed on these chemical laden subjects are glow worms.  Beetles in the genus Phengodes are silent assassins of millipedes.  The larva of the beetle sneaks up to the millipede and incredibly knows where to burrow in between the millipedes legs and cut the cord to the nervous system.  This prevents the millipede from using gas to deter the predator.  The glow worm can then dig its way into the millipede, eat it from the inside, and leave behind the exoskeleton.

Not a millipede (notice the 3 pairs of legs), this Phengodes plumosa larva feeds on millipedes.

Glow worm beetle larva bioluminescing (glowing) in the dark.  This millipede hunter produces light!



Glow worm larva sneaking in for the attack on a Narceus americanus.  It is burrowing its way into the center of the millipede.

Enjoy this video of a running millipede being chased by a predator (my camera) until all its legs get tired.  At the end of the video is a cute hatchling of a North American giant millipede.  The baby just hatched out of an egg which was enclosed in feces.  The feces ball, looking like a cocoa puff, is full of nutrients the juvenile eats to begin its life.  



Hopefully people admire the interesting millipedes they come across.  Not only are they a major player in decomposing the debris around us, but they are also interesting and attractive.  Even if their beauty is just a warning to stay away or you will be gassed.  Since their fossil records date back 420 million years, they are quite possibly the first breathing animals on land.  Now that deserves a little respect!
A big thanks to Derek Hennen for making the search for millipedes on our preserve so much fun.

Posted by: Mark Zloba