Class Diplopoda (Millipedes) in the Christopher B. Smith Preserve
Millipede Characteristics: Eighty-thousand millipede species are estimated to exist on Earth. Of this number, about 12,000 species in 140 families have been described. A millipede is an elongated, cylindrical or flattened, many-segmented arthropod. The head has a pair of antennae with 7 to 8 segments. Adult millipedes have two pairs of legs on most body segments. (The first four segments posterior of the head have a single pair only.) Each double-legged segment is actually two single segments that have fused. Most millipedes have more than 20 segments. The last segment has a telson.
Although the name "millipede" means mille ("thousand") and pes ("foot"), millipedes do not have a million legs. More common species have 36 to 400 legs. When crawling, the numerous legs appear to move in a slow, wave-like motion.
Since millipedes do not have a waxy cuticle like many other arthropods, they are susceptible to water loss. As a result, they live in moist areas. After mating, females lay 10 to 300 eggs at a time, depending on the species. Individuals live 1 to 10 years, depending on the species.
For defense, many millipede species curl into a tight coil to protect the fragile legs. The thick exterior protects the dorsal surfaces. Another defense some millipedes have a poisonous liquid secretion that can burn the exoskeleton of insect predators, and skin and eyes of larger predators. Order Polyxenida lacks armored exoskeletons and odiferous glands, but members are covered in bristles.
Various species of millipedes have been used in traditional medicine to treat fever, wounds, earaches, hemorrhoids, and convulsions in children.
Interactions in the Smith Preserve: Millipedes are part of the food chain. Most millipede species eat decaying vegetation, other species graze algae from bark or eat fungi. A few are omnivorous or carnivorous, consuming insects, centipedes, earthworms, and snails. Millipedes are preyed upon by insects, reptiles, amphibians, birds, and mammals, and parasitized by some thorny-headed worms, roundworms and marsh flies.
Order Family Species Name Common Name Spirobolida Spiroboidae Narceus americanus Polyxenida Polyxenidae Polyxenus sp. Polyxenida Unknown Unknown Polyzoniida Siphonotidae Rhinotus purpureus
Narceus americanus ... Worm Millipede
This species is a large cylindrical millipede native to Florida. It can be identified by its dark purplish-brown body with a thin band of red on the rear edge of each segment. The millipede in these photographs was dead and found under a fallen palm frond. It was about 4 cm long.
The photograph of the same specimen from a different angle is labeled below. Like most millipedes, this creature has two large eyes that have many light-sensitive parts called "ocelli," a small mouth, and two pairs of legs on most segments. Like insects, in order to grow, these millipedes must molt their exoskeletons.
Males, like the one in this photograph, have modified legs on the seventh segment called gonopods which they use during copulation to transfer sperm to females. Fertilization is internal.
When disturbed, a millipede curls into a spiral, produces a fecal pellet from its anal valve, and excretes a noxious fluid from pores on its sides. Despite all these ways of trying to protect itself, many are still consumed by reptiles, birds, small rodents, and predatory insects.
This species normally forages for food during the day under dead leaves. They are important decomposers of leaf litter and recyclers of nutrients.
Polyxenus sp. ... Fuzzy Millipede
On December 19, 2014, this 1 mm long millipede was living in leaf litter beneath a citrus tree in the hammock in the northeast corner of the Smith Preserve. The individual was isolated from the litter using a Berlese Funnel. These dorsal view (Image 1) and ventral view (Image 2) photographs were created using photomicroscopy.
On February 23, 2015, the millipede was identified from these photographs by Jeff Brown, a Contributor to <BugGuide.net>, sponsored by Iowa State University Department of Entomology, as a juvenile Polyxenus. He stated, "I believe Polyxenus fasciculatus, but it might not be possible to tell from the photo. Maybe Dr. Shelley will know." [Dr. Rowland Shelley is the Curator of Terrestrial Invertebrates at North Carolina Museum of Natural Sciences.]
Polyxenus fasciculatus is a species reaching about 2 mm in length as an adult. It is known to defend itself with its detachable bristles that entangle predatory ants. The bristles have grappling hooks at the tip which lock onto setae (hairs) of ants. Barbs along the bristle edges interlink with the ant setae.
This species is found in the eastern United States, Caribbean Islands and Canary Islands.
They are typically found in nature in litter and under bark, where they are active during the day, feeding on algae and lichens.
On February 24, 2014, the 1 mm-long individual shown below was living inside the curled leaf of a Ficus aurea (Strangler Fig) in the middle of the Smith Preserve.
On July 30, 2015, it was identified from this photograph as a polyxenid millipede by Mark Deyrup, Research Biologist at Archibold Biological Station in Lake Placid, Florida. Deyrup, along with Tom and Maria Eisner are credited with the paper titled, "Millipede defense: Use of detachable bristles to entangle ants," published in the Proceedings of the National Academy of Science, Vol. 93, pp. 10848-10851, October 1996.
Unknown Species ... Bristly Millipede / Pincushion Millipede
Members of Order Polyxenida have soft, non-calcified bodies, covered with tufts of bristles. The bristles are barbed and can easily detach and become entangled in the limbs and mouth parts of predatory insects. There are at least 160 described species and/or subspecies of bristly millipedes.
Bristly millipedes, like the one shown in these photographs are small and do not exceed 7 mm. This particular individual, 4 mm in length, was found inside a curled leaf of Ficus aurea (Strangler Fig) on February 6, 2014. The first photograph is the dorsal view, while the second photograph is the ventral view. This organism was identified as a Polyxenid millipede from these photographs on February 11, 2014 by Even Dankowicz, Contributor to <bugguide.net>, hosted by Iowa State Entomology Department.
Male Polyxenida do not have sperm-transferring appendages (gonopods) that other millipede orders have. Their sperm transfer is indirect, with each male depositing a spermatophore that is picked up by a female.
Many bristly millipede species reproduce asexually by parthenogenesis. In this type of reproduction, females lay eggs without mating and males are absent or rare.
Rhinotus purpureus ... Unknown Common Name
On February 10, 2016, this 13 mm long millipede was living in leaf litter in the northwest quadrant of Smith Preserve, north of Smith Preserve Way.
The individual was removed from the litter by using a Berlese funnel, and these photographs were created using photomicroscopy.
Photographs were sent for identification to <BugGuide.net>, sponsored by Iowa State University's Department of Entomology.
The photograph above shows the entire millipede. It appears to have ~50 segments. The photograph at right shows a dorsal view. Photographs below show the anterior and posterior ends of the millipede.
On March 5, 2016, the species was identified by Rowland Shelley, as an introduced species.
The species is native to tropical rainforests, but It is now found in Louisiana and southern Florida. As shown in the first photograph, this species is long and slim. It is a purplish-red color with a triangular head and large eye spots on either side of the head.
In South America and Madagascar, poison dart frogs have similar defense secretions. Both prey on this species of millipede and may sequester alkaloids from the millipedes to create their secretions.
© Photographs and text by Susan Leach Snyder (Conservancy of Southwest Florida Volunteer), unless otherwise credited above.
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