Centipede and millipede belong to group Myriapoda; subphylum consists of four classes of arthropods. They are not true insects because actually they more closely related to lobsters, crayfish and shrimp.
Both centipede and millipede share many characteristics as both have segmented bodies, found in moist habitats or areas with high humidity. They are active at night. Besides having many similarities, both centipedes and millipedes have many differences that make them possible to distinguish.
Centipede belongs to class Chilopoda are elongated, with flat, segmented bodies that contain a pair of long legs on each of their 15 or more-trunk segment. the word centipede arises from the Latin prefix centi-, meaning “hundred,” and pedis, meaning “foot.” They are one of the oldest animals on Earth. their common name is hundred-legged worms.
Centipede requires moist habitat because most of the centipede lacks the waxy epicuticle. They occur in several colors and patterns but the most common are grayish, brown, and reddish-orange while the subterranean ones, don’t have a specific color due to lack of pigmentation.
Centipede is known for its speed; fast-moving predators. They are carnivores feed on killing small arthropods, earthworms, and snails injecting them with venom, however some centipede feed on frogs and rodents. The venom of centipedes comes from glands located immediately beneath the centipede’s head. Maxillipeds (appendages modified to function as mouthparts k) along with mouth appendages they attack prey and hold the prey.
Centipede venom is harmless to humans thus when they bite humans there is less chance to produce a severe reaction. There are 8,000 species of centipedes. Centipedes have a varying number of legs, depends on the species, ranging from 30 to 354 (15 and 177 pairs) visibly extend from sides of the body; trail backward behind the body.
On the head, they have a pair of long antenna. There are different defensive mechanisms in centipedes that help to escape from the pray such as they use their fast moves to escape predators, inject venom to paralyze prey, and can squeeze prey with back legs. They also use prehensors, aposematic coloration, luminescence for the defense. They’re flexible and make swift, darting movements. Most centipedes are small, but some species exceed 10 inches.
Centipedes do not reproduce via direct copulation. Some species of centipede reproduce sexually while some reproduce through parthenogenesis. Female centipedes produce pheromones to attract mates and on average, the female centipede species lay 40 to 50 eggs. The male lays down a silk web using glands at the posterior end and produces in sperms in this web called spermatophore.
The spermatophore is either left for the female to find and take up or is brought to her attention via a courtship display and then introduce into her genital opening. Then the fertilized eggs are laid down in the soil or maybe some female centipedes guards’ eggs by wrapping her body around the eggs. Many centipedes young are similar to adults but have fewer pairs of legs than adults and acquire additional body segments and legs each time they molt.
Types of Centipede
There are different types of centipedes
- House centipedes: Night hunters, Scolopendra gigantea is an example of house centipede found in tropical and subtropical forests in northern South American.
- Amazonian giant centipede: is a large, fearsome and predatory arthropod has highly toxic venom that can quickly kill arthropods. Scolopendra gigantea is also an example of Amazonian giant centipede
- Texas redheaded centipede: Large centipede having 20 to 21 pairs of legs and appears dark-brown with a redhead. They can grow upto 8 inches. Scolopendra heros is the example of these centipede
- Stone centipedes: they mostly live under logs and rocks. Example of stone centipede is Lithobius forficatus found in Europe
- Soil centipedes: they dig the soil like earthworm by alternately expanding and contracting the body.
- Aquatic centipede: Scolopendra cataracta called waterfall centipede.
Millipedes belong to class Diplopoda, characterized by having two sets of legs (or four legs total) per body segment. Millipedes have 11 to 100 trunk segments derived from embryological and evolutionary fusion of primitive metameres. That is the reason they have pairs of appendages per body segment.
They have as many as 22 (11 pairs) to 750 (350 pairs) legs and their length range is 2 to 280 mm. The position of legs extended at most only slightly laterad and partial visible on the side of the body (short legs) that support the body of the millipedes and they can take off more substrate. The common name of millipedes is thousands legged worms. There are 7,000 species of millipede in the world but mostly millipedes found in America and north Africa.
They differ from centipede is that they don’t contain venom-injecting apparatuses and are non-poisons. Millipedes are worldwide distributed and they favor the habitat that prevent desiccation due to absence of waxy cuticle layer. Millipedes mostly are found under leaf litter humus or decaying logs.
Millipedes are detritivores because they feed on decaying organic matter such as dead vegetables, eat the roots and leaves of seedling plants therefore they are the agents of microbial decomposition and soil nutrient cycles. Millipeds are inflexible with variable body forms, slow-moving arthropods, and adapted for burrowing. But some species don’t have the capacity to burrow so these species are surface-active. The body of the millipede is divided into 11 to 150 segments.
Most of the millipedes are black or dark reddish-brown in color. Some species of millipedes secrete secretion for a defense that contains the noxious chemicals. The order Polydasmida release cyanide (possess repurgatorial glands that produce hydrogen cyanide) and coil into a ball (protective spiral) with head in center for the defense purpose.
The mouth of millipedes is dignathic with mandibles and gnathochilarium while the mouth of centipedes is trignathic with mandibles and first and second maxilla.
Reproduction in millipedes occurs through mating usually depositing sperm directly into the reproductive organs of the female. Male millipedes also transfer sperms through the gonopods to the female millipedes. Then female millipedes take up the sperm in her genital organ and lay down eggs in the soil. The eggs are hatch in several weeks.
Common millipedes’ species are
- Cylindroiulus Caeruleocinctus
- Tachypodoiulus niger (White legged Snake Millipede)
- Ommatoiulus sabulosus (Striped Millipede)
Large Millipedes species are
- Archispirostreptus Gigas (Giant African)
- Narceus americanus (American Giant)