Centipede

According to centipede meaning “Centipedes are predatory arthropods that are elongated metameric animals with a pair of legs per segment of the body”. The majority of centipedes are venomous generally and can inflict painful bites through forcipules, injecting their venom. Despite the name, the number of legs in the centipedes varies between 30 to 354. Centipedes always have a strange number of leg pairs. So no centipede has 100 legs exactly. Centipedes are predominantly carnivores, like spiders and Scorpions.

Centipedes are among the largest terrestrial invertebrate predators, and they frequently contribute significantly to the biomass of invertebrate predators in terrestrial ecosystems. An estimated 8,000 centipede species, 3,000 have been described, are reported around the world. Centipedes have broad geography, even beyond the Arctic Circle. They are found in a varied tropical rainforest to desert terrestrial habitats.

Taxonomy of Centipede

In this section, we will see the centipede classification scientifically.

• Centipedes belong to the kingdom Animalia.

• Centipede Phylum is Arthropoda.

• Their subphylum is Myriapoda.

• The class of centipede is Chilopoda.

• The centipede scientific name is Chilopoda.

Physical Characteristics and Anatomy of Centipede

• The head of a centipede is rounded or flattened, with a pair of antennae on the frontal border.

• They have two pairs of maxillae and two pairs of enlarged mandibles. The lower lip is formed by the first pair of maxillae, which have short palps.

• The first set of limbs extends forward from the body to cover the remaining mouth. These limbs, known as maxillipeds, include sharp claws and venom glands, which aid the animal in killing or paralysing its prey.

• Many centipede species lack eyes, but others have a variable number of ocelli that can be clustered together to form real compound eyes. These eyes, on the other hand, can only distinguish between light and dark and have no true vision.

• The first pair of legs at the head end of some centipede species function as sensing organs similar to antennae, however unlike most other animals antennae, theirs point backwards.

• Tomosvary organs are unusual sense organs seen in some groups. These are disc-like structures with a central hole surrounded by sensory cells that are found at the base of the antennae. They are most likely employed to detect vibrations and may perhaps offer hearing.

• Centipedes are the only arthropods with forcipules, and no other arthropods have them. The forcipules are extensions of the first pair of legs, the maxillipeds, that produce a pincer-like appendage that is always located behind the head.

• Although forcipules are used to acquire prey, inject venom, and hold onto trapped prey, they are not genuine mouthparts. Each forcipule has venom glands that go through a tube almost to the tip.

• The body of the centipede is made up of 15 or more segments behind the head. With the maxillipeds protruding forward from the first body segment and the final two segments being tiny and legless, the majority of the segments have only one pair of legs.

• Each pair of legs is slightly longer than the pair in front of it, ensuring that they do not overlap and, as a result, lowering the likelihood of colliding while travelling quickly. The last set of legs may be twice as long as the first pair in severe circumstances. The reproductive organs apertures are located in the last segment, which has a telson.

• Centipedes use their antennae to locate their prey as predators.

• With digestive glands linked to the mouthparts, the digestive tract forms a simple tube.

• Centipedes, like insects, breathe through a tracheal system, which has a single opening, or spiracle, on each of their body segments.

• They have a single pair of malpighian tubules that excrete waste.

The centipede diagram explains the complete anatomy of the centipede.

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Life Cycle of Centipede

• Centipedes do not reproduce through copulation. Males leave a spermatophore for females to accept.

• This spermatophore is deposited in a web in one clade, and the male performs a courtship dance to entice the female to swallow his sperm. In certain circumstances, males simply abandon them for the females to find.

• Egg-laying occurs in the spring and summer in temperate places, while there is little seasonality in centipede breeding in subtropical and tropical environments. There are only a few species of parthenogenetic centipedes.

• The centipede lays its eggs in holes in the dirt, which the female fills with soil. The number of eggs laid varies between 10 and 50.

• The time it takes for an embryo to develop from conception to hatching is highly variable, ranging from one to several months. Within and between species, the time from conception to reproduction is widely diverse.

• The eggs, which number between 15 and 60, are placed in a nest in the ground or in decaying wood.

• The female stays with the eggs, protecting them from fungus by guarding and washing them. In certain centipede species, the female stays with the young after they hatch, protecting them until they are ready to leave.

• Centipedes grow extra pairs of legs between moults, and their legs grow at distinct stages of development.

• Larval stadia are life phases with less than 15 pairs of legs. Following the completion of the entire set of legs, the now postlarval stadia produce gonopods, sensory pores, additional antennal segments, and ocelli. There are 15 leg-bearing segments on all mature lithobiomorpha centipedes.

• The number of leg-bearing segments ranges from 15 to 191, but because they are always added in pairs during the embryonic process, the total number of pairs is always odd.

Types of Centipedes

There are around 3000 centipede species described in the world. Here let us have a look at some of the important centipede orders and families.

Scutigeromorpha

• The Scutigeromorpha is an anamorphic creature with 15 leg-bearing segments.

• They're also known as house centipedes, and they're extremely swift and can resist rapid falls.

• When dropped, they can achieve speeds of up to 15 body lengths per second and survive the fall.

• They are the only centipede species that have retained their original compound eyes, which have a crystalline layer similar to that found in chelicerates and insects.

• They also have multi-segmented, long antennae.

• In other orders, adaptation to a burrowing lifestyle has resulted in the degeneration of compound eyes; this characteristic is extremely useful in the phylogenetic study.

• The Notostigmophora is distinguished by a single spiracle opening at the posterior of each dorsal plate, and the group is the only extant exemplar.

• Pleurostigmophora is the more evolved taxa, which have several spiracular holes on their sides.

• Several unpaired spiracles can be observed along the mid-dorsal line and closer to the posterior region of tergites in some individuals.

• Pselliodidae, Scutigeridae, and Scutigerinidae are the three families.

• Only a few species of the genus Sphendononema belong to the Pselliodidae, which can be found in the Neotropics and tropical Africa.

• The Scutigerinidae family is limited to southern Africa and Madagascar, with three species in the genus Scutigerina. The Scutigeridae includes two subfamilies, the Scutigerinae and the Thereuoneminae, which account for the majority of scutigeromorpha from different regions of the world.

Lithobiomorpha

• The main group of anamorphic centipedes is the Lithobiomorpha, also known as stone centipedes.

• They also have 15 trunk segments when they reach maturity.

• The compound eyes have been lost in this group, and they sometimes have no eyes at all. Instead, it has a single ocellus or a group of ocelli in its eyes.

• It has paired spiracles that can be found laterally.

• Apart from a pair of lengthy tergites on each of segments 7 and 8, every leg-bearing segment of this organism has its own tergite, which alternates in length.

• In comparison to the Scutigeromorpha, it also possesses short antennae and legs.

• Henicopidae and Lithobiidae are the two families of Lithobiomorpha.

Craterostigmomorpha

• The Craterostigmomorpha are the centipede group with the least diversity, with only two living species in the genus Craterostigmus.

• Their distribution is limited to Tasmania and New Zealand.

• Each side of the head capsule has a single ocellus.

• They have a specific body plan, and their anamorphosis occurs in a single step during their first moult when they increase from 12 to 15 segments.

• They have been compared to the platypus due to their low diversity and intermediary position between primitive anamorphic centipedes and evolved Epimorpha. 

• The Craterostigmomorpha and Epimorpha form the Phylactometria clade due to maternal brooding.

• This characteristic is assumed to be linked to the presence of sternal pores, which release sticky or toxic secretions that serve primarily to deter predators and parasites. Because the Devonian Devonobius has these pores, it may be classified as part of this clade, and its divergence may be dated to 375 million years ago or more.

Scolopendromorpha

• Except for Scolopendropsis duplicata, which has 39 or 43 segments with the same number of paired legs, the Scolopendromorpha, also known as tropical centipedes, have 21 or 23 body segments.

• They have 17 or more segments in their antennae.

• In the family Scolopendridae, the eyes have four ocelli on each side and one ocellus per side in the genus Mimops (family Mimopidae), but other families are blind.

• Cryptopidae, Scolopendridae, Mimopidae, Scolopocryptopidae, and Plutoniumidae are the five families that make up the order.

• Scolopendra cataracta and Scolopendra paradoxa, the only two known amphibious centipedes, are members of this order.

Geophilomorpha

• The Geophilomorpha, often known as soil centipedes, have up to 27 leg-bearing segments on their bodies.

• They are eyeless and blind, and have spiracles on all leg-bearing segments, unlike other groups, which only have them on the 3rd, 5th, 8th, 10th, 12th, and 14th segments. They have a mid-body break, accompanied by a change in tagmatic shape, that occurs roughly at the interchange between odd and even segments.

• With 1260 species, this category also has the largest and leggiest animals, with 27 or more pairs of legs.

• They also have antennae with 14 segments.

• The Geophilomorpha has seven families: Mecistocephalidae, Geophilidae including the former Linotaeniidae, Dignathodontidae and Macronicophilidae, Oryidae, Himantariidae, Schendylidae including the former Ballophilidae, Zelanophilidae, and Gonibregmatidae including the former Neogeophilidae and Eriphantidae.

Distribution of Centipedes

Centipedes can be found all over the planet, with the exception of Antarctica. As a result of commerce and plant introductions, several species have become more widespread, whether borne in soil or with plants. With the arrival of exotic mammals and snakes, certain species have vanished from islands.

Habitat of Centipedes

Centipedes are found in wet forests and woodlands, but many species also exist in dry forests, grasslands, and deserts. In the littoral zone, several Geophilomorpha seek seaweed clusters. Other species have a penchant for caves, and a few are cave-specific. Even for a single species, centipedes can endure elevations ranging from sea level to high mountain summits. Some species have very specialised microhabitats, such as decaying logs, however, the majority of species flourish in a variety of microhabitats, including logs, bark, litter, and under stones.

Ecology of Centipedes

• Centipedes are mostly generalist predators, meaning they have evolved to devour a wide range of different prey. Although centipedes have been known to eat vegetable materials when famished during laboratory tests, an examination of their gut contents reveals that plant material is an insignificant proportion of their diets.

• Centipedes are mostly active at night. Although a few observations of centipedes active during the day have been made, and one species, Strigamia chinophila, is diurnal, studies on their activity cycles substantiate this.

• Because of their cryptic lifestyles and thorough mastication of food, little is known about what centipedes eat.

• Centipedes will feed as generalists, consuming nearly everything soft-bodied and in a respectable size range, according to laboratory feeding trials. 

• Because geophilomorpha burrow through the dirt and earthworm bodies are easily penetrated by their venomous claws, earthworms may comprise the majority of their nutrition. Because geophilomorphs are unlikely to be able to control earthworms larger than themselves, smaller earthworms may make up a significant amount of their diet.

• Scolopendromorphs can eat vertebrates as well as invertebrates because of their size. Springtails may account for a significant amount of lithobiomorph diets. Diets of scutigeromorphs and craterostigmomorpha are little understood.

• Centipedes and spiders are known to prey on one other.

• Scolopendra cataracta and Scolopendra paradoxa, two amphibious species, are thought to hunt aquatic or amphibian invertebrates.

• Mongooses, mice, salamanders, beetles, and snakes are among the larger species that eat centipedes. Many species eat them, and some, like the African ant Amblyopone pluto, which eats only geophilomorph centipedes, and the South African Cape black-headed snake Aparallactus capensis, eat them exclusively.

• Centipedes use their speed and poisonous forcipules to defend themselves, as well as secreting protective compounds.

• Geophilomorph centipedes have small glands on their undersides that exude sticky substances that produce poisonous hydrogen cyanide and benzoic acid.

• Similarly, glands in the rear-most two pairs of legs of lithobiomorph centipedes release a sticky substance.

• Centipede ecology includes water regulation since they lose water quickly in dry environments and prefer moist microhabitats.

• Centipedes lack a waxy layer on their exoskeleton and excrete waste nitrogen as ammonia, which necessitates additional water.

• Centipedes have a range of adaptations to deal with water loss. Despite having a higher surface area to volume ratio, geophilomorphs lose water more slowly than lithobiomorphs. This could be because geophilomorphs have a pleural membrane that is more highly sclerotized.

• The rate of water loss is also influenced by the form, size, and ability of the spiracle to constrict. Furthermore, the quantity and size of coxal pores may influence centipede water balance.

• Centipedes can be found in a variety of environments, including forests, savannahs, prairies, and deserts.

• Some geophilomorphs have evolved to feed on barnacles in littoral settings.

• Except for the Craterostigmomorpha, species from all orders have adapted to caves.

Significance of Centipedes to Humans

• Certain huge centipedes are eaten as a culinary item in China, commonly skewered and grilled or deep-fried. They're common in large cities' street vendor booths, like Beijing's Donghuamen and Wangfujing markets.

• Large centipedes are also maintained in liquor for a period of time in China, as well as Laos, Thailand, and Cambodia. This practice is said to be part of traditional Chinese medicine. The liquor with the centipede buried in it is taken as a unique drink and is said to have therapeutic and reinvigorating powers.

• Because of their bite, some centipede species can be dangerous to humans. A bite to an adult person is usually excruciatingly painful and might result in significant swelling, chills, fever, and weakness, but it is unlikely to be fatal.

• Small children and individuals who are allergic to bee stings may be at risk from bites. Larger centipedes poisonous bites can cause anaphylactic shock in these persons. Centipedes with smaller bodies have a harder time piercing human skin.

Conclusion

Centipedes are nocturnal multisegmented elongated arthropods that have a pair of legs for each body segment except the last. The presence of forcipules, the modified initial segment upon which the headrests, distinguishes centipedes from superficially similar organisms. All centipedes are predators, however, they do occasionally eat leaf litter, which may be observed in their intestines. Centipedes are quick runners who actively seek for and capture little prey like collembolans. Centipedes are most frequent in tropical and subtropical areas, though they can be found on all six of the world's inhabited continents.