02-09-2017, 04:25 PM
Millipedes are a group of arthropods that are characterized by having two pairs of articulated legs in most body segments; are known scientifically as the Diplopoda class, the name derived from this characteristic. Each double leg segment is the result of two individual segments fused together. Most millipedes have very elongated cylindrical or flattened bodies with more than 20 segments, while pill millipedes are shorter and can roll in a ball. Although the name "millipedes" derives from the Latin of "thousand feet", no known species has 1,000; the record of 750 legs belongs to Illacme plenipes. There are about 12,000 species named classified in 16 orders and about 140 families, making Diplopoda the largest class of myriapods, a group of arthropods that also includes centipedes and other multi-legged creatures.
Most millipedes are detritivores of slow movement, eating decaying leaves and other dead vegetable matter. Some eat mushrooms or suck vegetable fluids, and a small minority are predators. Millipedes are generally harmless to humans, although some can become household or garden pests, especially in greenhouses where they can cause severe damage to emerging seedlings. Most millipedes are defended with a variety of chemical substances secreted by pores throughout the body, although the small millipedes of bristles are covered with bundles of removable bristles. Reproduction in most species is carried out by modified male legs called gonopods, which transfer the sperm packets to the females.
Appearing for the first time in the Silurian period, millipedes are some of the oldest known land animals. Some members of prehistoric groups grew more than 2 m (6 feet 7 inches); the largest modern species reach maximum lengths of 27 to 38 cm (11 to 15 inches). The oldest species that exists is the African giant (Archispirostreptus gigas).
Among the myriapods, millipedes have traditionally been considered more closely related to the tiny pauropods, although some molecular studies question this relationship. Millipedes are distinguished from centipedes (class Chilopoda), somewhat similar but only distantly related, that move quickly, are carnivorous and only have a pair of legs in each segment of the body. The scientific study of the millipedes is known as diplopodology, and a scientist who studies them is called a diplopodologist.
Most millipedes are detritivores of slow movement, eating decaying leaves and other dead vegetable matter. Some eat mushrooms or suck vegetable fluids, and a small minority are predators. Millipedes are generally harmless to humans, although some can become household or garden pests, especially in greenhouses where they can cause severe damage to emerging seedlings. Most millipedes are defended with a variety of chemical substances secreted by pores throughout the body, although the small millipedes of bristles are covered with bundles of removable bristles. Reproduction in most species is carried out by modified male legs called gonopods, which transfer the sperm packets to the females.
Appearing for the first time in the Silurian period, millipedes are some of the oldest known land animals. Some members of prehistoric groups grew more than 2 m (6 feet 7 inches); the largest modern species reach maximum lengths of 27 to 38 cm (11 to 15 inches). The oldest species that exists is the African giant (Archispirostreptus gigas).
Among the myriapods, millipedes have traditionally been considered more closely related to the tiny pauropods, although some molecular studies question this relationship. Millipedes are distinguished from centipedes (class Chilopoda), somewhat similar but only distantly related, that move quickly, are carnivorous and only have a pair of legs in each segment of the body. The scientific study of the millipedes is known as diplopodology, and a scientist who studies them is called a diplopodologist.