Millipedes are a group of arthropods that are characterised by having two pairs of jointed legs on most body segments; they are known scientifically as the class Diplopoda, the name derived from this feature. Each double-legged segment is a result of two single 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 into a tight ball. Typically forest floor dwellers, they live in leaf litter, dead wood, or soil, with a preference for humid conditions. Millipedes generally have little impact on human economic or social well-being, especially in comparison with insects, although locally they can be a nuisance or agricultural pest.
Millipedes do not bite, and their defensive secretions are mostly harmless to humans — usually causing only minor discolouration on the skin — but the secretions of some tropical species may cause pain, itching, local erythema, edema, blisters, eczema, and occasionally cracked skin. Eye exposures to these secretions causes general irritation and potentially more severe effects such as conjunctivitis and keratitis. This is called millipede burn. First aid consists of flushing the area thoroughly with water; further treatment is aimed at relieving the local effects.
Cockroaches or roaches are a paraphyletic group of insects belonging to Blattodea, containing all members of the group except termites. About 30 cockroach species out of 4,600 are associated with human habitats. Some species are well-known as pests. Some species, such as the gregarious German cockroach, have an elaborate social structure involving common shelter, social dependence, information transfer and kin recognition.
Cockroaches have appeared in human culture since classical antiquity. They are popularly depicted as dirty pests, although the majority of species are inoffensive and live in a wide range of habitats around the world. Cockroaches are among the hardiest insects. Some species are capable of remaining active for a month without food and are able to survive on limited resources. They feed on human and pet food and can leave an offensive odor. They can passively transport pathogenic microbes on their body surfaces, particularly in environments such as hospitals.
Cockroaches are linked with allergic reactions in humans. One of the proteins that trigger allergic reactions is tropomyosin, which can cause cross-reactive allergy to dust mites and shrimp. These allergens are also linked with asthma. Some species of cockroach can live for up to a month without food, so just because no cockroaches are visible in a home does not mean that they are not there. Approximately 20–48% of homes with no visible sign of cockroaches have detectable cockroach allergens in dust.
Spiders (order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species diversity among all orders of organisms. Spiders are found worldwide on every continent except for Antarctica, and have become established in nearly every land habitat.
As of August 2022, 50,356 spider species in 132 families have been recorded by taxonomists. Although spiders are widely feared, only a few species are dangerous to people. Spiders will only bite humans in self-defense, and few produce worse effects than a mosquito bite or bee sting. Most of those with medically serious bites, such as recluse spiders (genus Loxosceles) and widow spiders (genus Latrodectus), would rather flee and bite only when trapped, although this can easily arise by accident.
he defensive tactics of Australian funnel-web spiders (family Atracidae) include fang display. Their venom, although they rarely inject much, has resulted in 13 attributed human deaths over 50 years. They have been deemed to be the world’s most dangerous spiders on clinical and venom toxicity grounds, though this claim has also been attributed to the Brazilian wandering spider (genus Phoneutria).
Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus Rattus. Other rat genera include Neotoma (pack rats), Bandicota (bandicoot rats) and Dipodomys (kangaroo rats). Rats are typically distinguished from mice by their size. Usually the common name of a large muroid rodent will include the word “rat”, while a smaller muroid’s name will include “mouse”.
The common terms rat and mouse are not taxonomically specific. There are 56 known species of rats in the world. The best-known rat species are the black rat (Rattus rattus) and the brown rat (Rattus norvegicus). This group, generally known as the Old World rats or true rats, originated in Asia. Rats are bigger than most Old World mice, which are their relatives, but seldom weigh over 500 grams (17+1⁄2 oz) in the wild.
Rats can serve as zoonotic vectors for certain pathogens and thus spread disease, such as bubonic plague, Lassa fever, leptospirosis, and Hantavirus infection.[46] Researchers studying New York City wastewater have also cited rats as the potential source of “cryptic” SARS-CoV-2 lineages, due to unknown viral RNA fragments in sewage matching mutations previously shown to make SARS-CoV-2 more adept at rodent-based transmission.
Spiders (order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species diversity among all orders of organisms. Spiders are found worldwide on every continent except for Antarctica, and have become established in nearly every land habitat.
Some species are well-known as pests. Some species, such as the gregarious German cockroach, have an elaborate social structure involving common shelter, social dependence, information transfer and kin recognition. Cockroaches have appeared in human culture since classical antiquity. They are popularly depicted as dirty pests, although the majority of species are inoffensive and live in a wide range of habitats around the world. Cockroaches are among the hardiest insects. Some species are capable of remaining active for a month without food and are able to survive on limited resources.
They feed on human and pet food and can leave an offensive odor. They can passively transport pathogenic microbes on their body surfaces, particularly in environments such as hospitals. Cockroaches are linked with allergic reactions in humans, One of the proteins that trigger allergic reactions is tropomyosin, which can cause cross-reactive allergy to dust mites and shrimp. These allergens are also linked with asthma. Some species of cockroach can live for up to a month without food, so just because no cockroaches are visible in a home does not mean that they are not there. Approximately 20–48% of homes with no visible sign of cockroaches have detectable cockroach allergens in dust.
Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of 22,000 species have been classified. They are easily identified by their geniculate (elbowed) antennae and the distinctive node-like structure that forms their slender waists.
Ants form colonies that range in size from a few dozen predatory individuals living in small natural cavities to highly organised colonies that may occupy large territories and consist of millions of individuals. Larger colonies consist of various castes of sterile, wingless females, most of which are workers (ergates), as well as soldiers (dinergates) and other specialised groups. the presence of ants would be undesirable in sterile places such as hospitals or kitchens.
Some species or genera commonly categorized as pests include the Argentine ant, immigrant pavement ant, yellow crazy ant, banded sugar ant, pharaoh ant, red wood ant, black carpenter ant, odorous house ant, red imported fire ant, and European fire ant. Some ants will raid stored food, some will seek water sources, others may damage indoor structures, some may damage agricultural crops directly or by aiding sucking pests. Some will sting or bite. The adaptive nature of ant colonies make it nearly impossible to eliminate entire colonies and most pest management practices aim to control local populations and tend to be temporary solutions.
Flea, the common name for the order Siphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by ingesting the blood of their hosts. Fleas feed on a wide variety of warm-blooded vertebrates including dogs, cats, rabbits, squirrels, ferrets, rats, mice birds, and sometimes humans. Fleas normally specialise in one host species or group of species, but can often feed but not reproduce on other species.
Ceratophyllus gallinae affects poultry as well as wild birds. As well as the degree of relatedness of a potential host to the flea’s original host, it has been shown that avian fleas that exploit a range of hosts, only parasitise species with low immune responses.
Fleas are principally a nuisance to their hosts, causing an itching sensation which in turn causes the host to try to remove the pest by biting, pecking, or scratching. Fleas are not simply a source of annoyance, however. Flea bites cause a slightly raised, swollen, irritating nodule to form on the epidermis at the site of each bite, with a single puncture point at the center, like a mosquito bite.
Trombiculidae commonly referred to in North America as chiggers and in Britain as harvest mites, but also known as berry bugs, bush-mites, red bugs or scrub-itch mites, are a family of mites. Chiggers are often confused with jiggers – a type of flea. Several species of Trombiculidae in their larva stage bite their animal or human host and by embedding their mouthparts into the skin cause “intense irritation” or “a wheal, usually with severe itching and dermatitis”.
Trombiculidae live in forests and grasslands and are also found in the vegetation of low, damp areas such as woodlands, berry bushes, orchards, along lakes and streams, and even in drier places where vegetation is low, such as lawns, golf courses, and parks.
They are most numerous in early summer when grass, weeds, and other vegetation are heaviest. In their larval stage, they attach to various animals, including humans, and feed on skin, often causing itching. Because chigger wounds are a complex combination of enzymatic and the resulting mechanical damage, plus allergy and immune responses, plus possible secondary bacterial infection subject to local influences, no one remedy works equally well for most people.
The silverfish is a species of small, primitive, wingless insect in the order Zygentoma. Its common name derives from the insect’s silvery light grey colour, combined with the fish-like appearance of its movements.
Silverfish are considered household pests, due to their consumption and destruction of property.However, although they are responsible for the contamination of food and other types of damage, they do not transmit disease.Earwigs, house centipedes, and spiders such as the spitting spider Scytodes thoracica are known to be predators of silverfish.
Centipedes can be found in a wide variety of environments. They normally have a drab coloration combining shades of brown and red. Cavernicolous (cave-dwelling) and subterranean species may lack pigmentation, while many tropical scolopendromorphs have bright aposematic colors. Worldwide, an estimated 8,000 species of centipedes are thought to exist, of which 3,000 have been described. Centipedes have a wide geographical range, even reaching beyond the Arctic Circle.
They are found in an array of terrestrial habitats from tropical rainforests to deserts. Within these habitats, centipedes require a moist microhabitat because they lack the waxy cuticle of insects and arachnids, therefore causing them to rapidly lose water.[6] Accordingly, they are found in soil and leaf litter, under stones and dead wood, and inside logs.
species of centipedes can be hazardous to humans because of their bite. While a bite to an adult human is usually very painful and may cause severe swelling, chills, fever, and weakness, it is unlikely to be fatal. Bites can be dangerous to small children and those with allergies to bee stings. The venomous bite of larger centipedes can induce anaphylactic shock in such people. Smaller centipedes are generally incapable of piercing human skin.
Earwigs make up the insect order Dermaptera. With about 2,000 species in 12 families, they are one of the smaller insect orders. Earwigs have characteristic cerci, a pair of forcep-like pincers on their abdomen, and membranous wings folded underneath short, rarely used forewings, hence the scientific order name, “skin wings”. Some groups are tiny parasites on mammals and lack the typical pincers
Earwigs are mostly nocturnal and often hide in small, moist crevices during the day, and are active at night, feeding on a wide variety of insects and plants. Damage to foliage, flowers, and various crops is commonly blamed on earwigs, especially the common earwig Forficula auricularia. Earwigs are fairly abundant and are found in many areas around the world.
There is no evidence that they transmit diseases to humans or other animals. Their pincers are commonly believed to be dangerous, but in reality, even the curved pincers of males cause little or no harm to humans. Earwigs have been rarely known to crawl into the ears of humans,[58] but they do not lay eggs inside the human body or human brain as is often claimed.
Termites are small insects that live in colonies and have distinct castes (eusocial) and feed on wood or other dead plant matter. About 3,106 species are currently described, with a few hundred more left to be described. Although these insects are often called “white ants”,they are not ants, and are not closely related to ants.
Termites have several effects on humans. They are a delicacy in the diet of some human cultures and are used in many traditional medicines. Several hundred species are economically significant as pests that can cause serious damage to buildings, crops, or plantation forests. Some species, such as the West Indian drywood termite (Cryptotermes brevis), are regarded as invasive species.
A total of 26 species of termites were present in the three sites, and 196 encounters were recorded in the transects. The termite assemblages were considerably different among sites, with a conspicuous reduction in both diversity and abundance with increased disturbance, related to the reduction of tree density and soil cover, and with the intensity of trampling by cattle and goats. The wood-feeders were the most severely affected feeding group.
