SYMPHYLANS: SymphylaGARDEN SYMPHYLAN (Scutigerella immaculata): SPECIES ACCOUNT
The soft, whitish bodies of symphylans (sim-FIL-ehns) are long and slender, measuring 0.078 to 0.31 inches (2 to 8 millimeters) in length. The head is distinct, heart-shaped and has three pairs of mouthparts. One pair is fused together to form a lower lip. The antennae (an-TEH-nee), or sense organs, are long and threadlike or beadlike. There are no eyes. The body has fourteen segments. The back of the body is covered with fifteen to twenty-four soft plates. The first twelve body segments each have a pair of legs. At the base of each leg is a short stiff spine and special sac. The spine probably helps the symphylan move through the soil, while the sac probably regulates water and salts in the body. The next-to-last body segment has a pair of projections from which the symphylans produce silk. The last body segment has a pair of long, sensitive hairlike structures.
Symphylans are found on all continents except Antarctica. There are about two hundred species worldwide. The species in the United States and Canada are so poorly studied that it is not known just how many species there are.
Symphylans live in the upper 3.2 foot (1 meter) layers of soil in both natural and agricultural habitats. They prefer moist but not wet soils.
Symphylans eat mainly roots and rootlike structures of funguses, but most species are probably omnivorous (am-NI-vo-rus), or animals that feed on both plant and animal materials.
BEHAVIOR AND REPRODUCTION
Symphylans are usually found in large numbers and sometimes gather in groups. They move up and down in the soil to maintain the proper moisture levels in their surroundings. Their antennae move constantly as they move about searching for food and mates, but they are held back over the body when feeding. Symphylans run swiftly, especially when threatened.
Males and females are both required for reproduction. Males deposit sperm packets on the ground. The females later pick up the sperm packets in their mouths. Nothing else is known about their courtship behavior or how they might communicate or interact with each other. Females deposit up to twenty-five pearly-white eggs in a mass. The hatchlings have fewer body segments than adults and only six or seven pairs of legs. They are very inactive. Each time they molt, or shed their exoskeleton or hard outer covering, they will add an additional segment and pair of legs until they reach adulthood with twelve pairs.
SYMPHYLANS AND PEOPLE
Symphylans are small, secretive animals that do not bite or sting and are largely unknown to the public. Garden symphylans damage crops such as pineapple, beets, potatoes, beans, and many others. They are sometimes a pest in greenhouses.
LIKE TWO SHIPS PASSING IN THE NIGHT
Males and females of Scutigerella do not have be in the same place at the same time to reproduce. Each male produces up to 450 sperm packets and places them on top of short stalks of silk. Later, females walk through the patches of packets and gobble up to eighteen each day. Most are swallowed and digested, but some are stored in special sacs in her mouth. Afterward she gently removes each egg from her reproductive organs and fertilizes them in her mouth.
No symphylan is considered endangered or threatened. However, symphylans are not very well known, and it is possible that species found only in limited areas could be vulnerable to extinction if their habitats were spoiled or destroyed.
Physical characteristics: This species measures 0.19 to 0.31 inches (5 to 8 millimeters) in length. Their bodies are whitish or light brownish. They are impossible to identify without examination through a microscope.
Geographic range: The true range of this species is unknown because it is often confused with other closely related species.
Habitat: This species lives in leaf litter and rich soil. It is also found in agricultural fields and greenhouses.
Diet: The garden symphylan eats vegetable material, especially small roots and rootlike parts of funguses.
Behavior and reproduction: The adults are especially quick when threatened.
Males leave sperm packets on the ground for females to pick up. Eggs are laid in masses, each mass containing up to twenty-five eggs. The larvae (LAR-vee), or young, hatch with six or seven pairs of legs and add a new pair of legs with each molt.
Garden symphylans and people: This species is sometimes a serious pest in fields, gardens, and greenhouses and hothouses.
Conservation status: Garden symphylans are not considered endangered or threatened. ∎
FOR MORE INFORMATION
Edwards, C. A. Symphyla: In Soil Biology Guide, edited by Daniel L. Dindal. New York: John Wiley and Sons, 1990.
Eisenbeis, G., and W. Wichard, Atlas on the Biology of Soil Arthropods. Berlin, Germany: Springer-Verlag, 1987.
Scheller, U. "Symphyla from the United States and Mexico." Texas Memorial Museum, Speleological Monographs 1 (1986): 87–125.
"Symphyla." Tree of Life Web Project. http://tolweb.org/tree?group=Symphyla&contgroup=Arthropoda (accessed on November 3, 2004).
Tasmanian Symphyla. http://www.qvmag.tas.gov.au/zoology/multipedes/tassymph/symintro.html (accessed on November 3, 2004).