HOME: www.hiltonpond.org

GENERAL INFO

CONTENTS

RESEARCH

EDUCATION

PUBLICATIONS

MISCELLANY

NIGHT OF A THOUSAND LEGS

Such was the case this week when we were up well before dawn and walking along one of the Center's trails. Our flashlight of preference is a headlamp that frees both hands and allows us to aim the beam exactly where we're looking. As we rounded a bend in the trail, we pointed the light downward and spotted something moving slowly across the path. It looked like a shiny brown tube, but there was little doubt about its identity: it was a "thousand-legger," or millipede.

Despite their name, millipedes don't really have a thousand legs, but they seem to. Most species bear two pairs of legs on all but the first several segments--each of which has only a single pair; the photo below posterior shows quartets of legs on the millipede's posterior segments. Since the specimen we found at Hilton Pond Center had 48 segments (not counting the head and tail) that means, if we calculate correctly, this particular millipede had, hmmm, let's see, 48 minus 5 segments with only one pair each is 43, times 4 is 172 legs, plus 2 legs times 5 segments is 10, equals, hmmm, a total of 182 legs. It's hard enough for us to just count these appendages, so it's a real wonderment that a millipede is able to coordinate them all and move about so effortlessly by night on the forest floor.

Millipedes are in the Diplopoda, the invertebrate class whose name actually translates as "double feet" and refers to those segments with two pairs of legs. "Thousand-legger" millipedes are distantly related to the centipedes (Class Chilopoda), which are "hunnert-leggers" with only a single pair of legs per segment. Centipedes are more likely to be encountered by humans, since they often hang out in basements and in spring have been known to migrate in large numbers up from the cellar, across the living room, down the hall, and out into the night . . . and sometimes back. (In fairness, we should mention that a few house-loving millipede species exhibit this same behavior.) Centipedes--which prey on insects and spiders--have menacing pincer-like mouthparts that in large specimens are capable of inflicting a painful bite and injecting poison. Curiously, these poison jaws are really modified legs; "Chilopoda" loosely translates as "lip foot."

Our millipede, a far gentler organism, doesn't nip but defends itself in a quite different manner, as we were reminded when we picked it up on the trail. If disturbed most millipedes protet their heads by curling into a tight spiral and often produce a fecal pellet (below right); if that fails to dissuade potential predators, some millipedes excrete from pores on their sides an repugnant fluid that-- according to some experts-- is strong enough to kill an insect placed in a container with the millipede. To our nostrils, the potent chemical smells slightly sweet and in some cases reminds us of wild cherries--not surprising since the millipede juice is reported to contain hydrogen cyanide, a compound also found in cherry leaves. (NOTE: Experts claim some millipedes excrete benzoquinones and a assortment of other chemicals other than cyanide.) And--as we accidentally found out while handling this week's millipede for photographic purposes--the fluid can discolor human skin to about the same shade as brownish nicotine stains we've seen on the fingers of heavy smokers. We were pleased to note, however, that our specimen was NOT one of those whose excretions irritate the eyes or cause epidermal blistering. Despite their noxious fluids, millipedes are a favorite food of toads, lizards, birds, small rodents, and some predatory insects.

The majority of the 1,400 known species of North American millipedes dine on decaying vegetable matter and fungi and play a crucial role in decomposition of leaf litter and nutrient cycling. Some species browse on roots, stems, or leaves of live plants and can cause problems in the garden, while a very few millipedes have modified mouthparts that allow them to take live prey such as insects and earthworms. As demonstrated by our encounter this week, most millipedes are creatures of the dark that forage by day beneath dead leaves and occasionally venture forth at night. Outdoors they overwinter as adults and emerge in spring, perhaps using their sensitive antennae (top photo and below right) to scan the air for some of that enticing hydrogen cyanide and/or benzoquinone given off by a prospective mate. When a partner is encountered, copulation ensues, with sperm being guided into the female by modified legs on the male's seventh segment; the specimen we found was a female with all legs being similar in structure (above left). After mating, the female goes off to lay her clutch of up to 300 white eggs in a small soil depression that she sometimes defends. Eggs hatch within a few weeks to produce tiny millipedes with only three pairs of legs. As the offspring grow, a few new pairs of legs are produced with each successive molt. Individual millipedes can live for several years in a terrarium; folks collect, raise, and trade these multi-legged invertebrates, some of which are even sold in pet shops.

The specimen we found this week at Hilton Pond Center is Narceus americanus; at four inches long and a half-inch in diameter, it is by far the largest millipede in the Carolina Piedmont. In comparison, the common Garden Millipede, Oxidus gracilis, is less than an inch in length and only an eight of an inch wide.

N. americanus, which seems to have no common name, occurs across much of the eastern U.S. and into southern Canada; it is identifiable by a dark purplish-brown body with a thin band of red on the rear edge of each segment. Like most millipedes, it has two large compound eyes made up of many tiny light-sensitive dots called "ocelli" (right), and its mouthparts are relatively small. No one knows how old this particular species might be, but it comes from ancient lineage. The earliest millipedes date back 420 million years, making them the oldest surviving group of terrestrial arthropods and almost twice as old as the earliest dinosaurs. Their general body structure has changed little since the mid-Paleozoic Era, which means millipedes have had plenty of time to work on coordinating those millions, er, thousands, no, hundreds of legs that help them navigate the trails by night here at Hilton Pond Center.

--SEARCH OUR SITE--
You may wish to consult our Index of all nature topics covered since
February 2000, or use our on-line Hilton Pond Search Engine:

For your very own on-line subscription to "This Week at Hilton Pond,"
just click on the image above. It's guaranteed fat-free!

Thanks to the following fine folks for recent gifts in support of Hilton Pond Center for Piedmont Natural History and/or Operation RubyThroat: The Hummingbird Project. Your tax-deductible contributions allow us, among other things, to continue writing, photographing, and sharing "This Week at Hilton Pond" with students, teachers, and the general public. Please see Support or scroll below if you'd like to make a gift of your own.

We're pleased folks are thinking about the work of the Center and making donations. Those listed below made contributions received during the period. Please join them if you can in coming weeks.

Gifts can be made via PayPal (funding@hiltonpond.org); credit card via Network for Good (see link below); or personal check (c/o Hilton Pond Center, 1432 DeVinney Road, York SC 29745).

• None this week
  
  

If you enjoy "This Week at Hilton Pond," please help support
Hilton Pond Center for Piedmont Natural History.
It's painless, and YOU can make a difference!

(Just CLICK on a logo below or send a check if you like; see Support for address.)

Make credit card donations
on-line via
Network for Good:

Use your PayPal account
to make direct donations:

If you like shopping on-line please become a member of iGive, through which 1,500+ on-line stores from Amazon to Lands' End and even iTunes donate a percentage of your purchase price to support Hilton Pond Center. Every new member who registers with iGive and makes a purchase through them earns an ADDITIONAL $5 for the Center. You can even do Web searches through iGive and earn a penny per search--sometimes TWO--for the cause! Please enroll by going to the iGive Web site. It's a painless, important way for YOU to support our on-going work in conservation, education, and research. Add the iGive Toolbar to your browser and register Operation RubyThroat as your preferred charity to make it even easier to help Hilton Pond Center when you shop.

The Piedmont Naturalist--Vol. 1--1986 (Hilton Pond Press) is an award-winning collection of newspaper columns that first appeared in The Herald in Rock Hill SC. Optimized for tablets such as iPad and Kindle, electronic downloads of the now out-of-print volume are available by clicking on the links below. The digital version includes pen-and-ink drawings from the original edition--plus lots of new color photos. All sales go
to support the work of Hilton Pond Center.

Please report your sightings of
Color-marked
Ruby-throated
Hummingbirds

---

OTHER SIGHTINGS OF INTEREST