Centipedes and millipedes are distant relatives of lobsters, crayfish and shrimp. Unlike their marine cousins, centipedes and millipedes are land dwellers, but they do prefer moist habitats or areas of high humidity.
Centipedes and millipedes do not carry diseases to man or to his animals and plants. They are usually considered nuisances rather than destructive pests. Centipedes pose an occasional threat to man because they have poison glands and will bite. Millipedes occasionally damage seedling plants by feeding on stems and leaves
There are many kinds of centipedes but all of them are more or less wormlike and have a flattened body. The largest centipede inhabits the tropics of Central America. Scolopendra gigantca is its name and when fully mature will attain a length of 12 inches. A closely related centipede, Scolopendra heros, occurs in Texas and may be over 5 inches long when full grown.
Like all centipedes, Scolopendra can inflict a painful bite with a pair of poison claws located directly under the head. These poison claws, once a pair of walking legs, have undergone a drastic change over thousands of years and are now used for capturing and killing their prey instead of walking. So complete is the change and so close is the association with the head, the claws now appear to be mouth parts.
Most centipedes can only bite with their poison claws located directly under the head; however, Scolopendra can harm a person with the sharp claws of its many walking legs. Each walking leg is tipped with a sharp claw capable of making tiny cuts in human skin. A poison produced from the attachment point of each leg may be dropped into the wounds resulting in an inflamed and irritated condition. The best rule of thumb is NEVER HANDLE CENTIPEDES.
Millipedes differ from centipedes in that most body segments are more round and bear two pairs of appendages on each segment instead of one. The head is rounded with short antennae and does not contain poison jaws.
Biology and Habits
Centipedes are long-lived; some have been known to live up to 6 years. Most species feed upon small creatures such as insects. With the powerful jaws located immediately under the head they grasp and kill their prey by injecting venom. Occasionally, man may be bitten by centipedes but the poison usually produces only a moderate reaction similar to a bee sting. The only concern would be to those allergic to insect venoms and other toxins, particularly small children. In cases involving severe reactions, consult a physician at once.
Centipedes may be found in a variety of habitats but prefer moist, protected places such as under stones, rotted logs, leaves or bark. They spend the winter as adults and lay eggs during the warm months. Generally, eggs are laid in the soil and covered by a sticky substances. A few species give birth to living young.
The house centipede, Scutigera coleoptrata, originally lived only in Mexico but is now found throughout the United States. It is the only species capable of reproducing in houses and is often seen in and around homes where dampness occurs. The house centipede is active at night, moving about in search of insects. When full grown it is about 1 1/2 inches in Iength and feeds primarily on small insects such as cockroaches, clothes moths, house flies and other insects it may encounter in the house. The long back legs capture the prey with a “lassoing” action. Although centipedes are beneficial in that they destroy other insects, most people have an aversion to their presence in homes.
Millipedes are not poisonous, but many species have repugnatorial glands capable of producing irritating fluids which may produce allergic reactions in individuals sensitive to insects or insect toxins. A few millipede species are capable of squirting these fluids over a distance of several inches. Persons handling millipedes will notice a lingering odor on their hands and the fluid can be dangerous to the eyes. It is not advisable to handle millipedes, but when one has been held, hands should be washed with soap and water until the odor is completely gone.
Millipedes feed primarily on decaying organic matter, but may attack roots and leaves of seedling plants. Greenhouses are infested by millipedes more often than other areas where plants are grown. Once a greenhouse becomes infested, control measures usually are necessary.
Controlling centipedes and millipedes outdoors includes removing objects that provide harborage such as trash piles, rocks, boards, leaf piles, compost piles and similar materials. If millipedes and centipedes occur in great numbers or are creating problems, sprays or dusts containing diazinon, malathion, carbaryl, propoxur, pyrethrin or resmethrin applied around building foundations may provide some control.
When treating inside the home, baseboards, cracks, crevices or other hiding places such as under clothes washers and dryers in utility rooms may be sprayed with products containing resmethrin or carbaryl. Contact sprays of propoxur or pyrethrins may be applied directly to centipedes and millipedes for quick control.
Carbaryl or diazinon granules may be used on turf. They perform better than dusts or sprays in this situation. Baits containing mesurol (slug and snail bait) also aid in controlling millipedes.