Subclass

CHAPTER

phylum class subclass order monotypic order suborder family

PHYSICAL CHARACTERISTICS

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.

GEOGRAPHIC RANGE

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.

HABITAT

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.

DIET

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 symphy-lans damage crops such as pineapple, beets, potatoes, beans, and many others. They are sometimes a pest in greenhouses.

CONSERVATION STATUS

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.

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.

SPECIES ACCOUNT

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