Ticks are small arachnids in the order Parasitiformes. Along with mites, they constitute the subclass Acarina. Ticks are ectoparasites, living by hematophagy on the blood of mammals, birds, and sometimes reptiles and amphibians.
Mosquitoes are a family of small, midge-like flies: the Culicidae. Although a few species are harmless or even useful to humanity, the females of most species are ectoparasites whose tube-like mouthparts pierce the hosts' skin to suck the blood.
Owing to their wood-eating habits, many termite species can do great damage to unprotected buildings and other wooden structures. Their habit of remaining concealed often results in their presence being undetected until the timbers are severely damaged and exhibit surface changes. Once termites have entered a building, they do not limit themselves to wood; they also damage paper, cloth, carpets, and other cellulosic materials. Particles taken from soft plastics, plaster, rubber, and sealants such as silicone rubber and acrylics are often employed in gallery construction.
Bees may be solitary or may live in various types of communities. The most advanced of these are eusocial colonies found among the honey bees, bumblebees, and stingless bees. Although a bee sting can be deadly to those with allergies, virtually all bee species are non-aggressive if undisturbed and many cannot sting at all.
Although spiders are widely feared, only a few species are dangerous to people. Most 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 and widow spiders, are shy and bite only when they feel threatened, although this can easily arise by accident.
Some rodent species are serious agricultural pests, eating large quantities of food stored by humans. Most of the damage worldwide is caused by a relatively small number of species, chiefly rats and mice. Rodents are also significant vectors of disease.
Moths, and particularly their caterpillars, are a major agricultural pest in many parts of the world. Several moths in the family Tineidae are commonly regarded as pests because their larvae eat fabric such as clothes and blankets made from natural proteinaceous fibers such as wool or silk.
Some species of centipede can be hazardous to humans because of their bite. Although 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 bite of larger centipedes can induce anaphylactic shock in such people. Smaller centipedes usually do not puncture human skin.
Cockroaches are one of the most commonly noted household pest insects. They feed on human and pet food and can leave an offensive odor. They can also passively transport microbes on their body surfaces including those that are potentially dangerous to humans, particularly in environments such as hospitals. Cockroaches are linked with allergic reactions in humans. One of the proteins that triggers allergic reactions is tropomyosin. These allergens are also linked with asthma.
The presence of a single pair of patent, mesothoracic flight wings distinguishes most true flies from other insects with "fly" in their names, such as mayflies, dragonflies, damselflies, stoneflies, whiteflies, fireflies, alderflies, dobsonflies, snakeflies, sawflies, caddisflies, butterflies or scorpionflies.
About 75% of beetle species are phytophagous in both the larval and adult stages, living in or on plants, wood, fungi, and a variety of stored products, including cereals, tobacco, and dried fruits. Because many of these plants are important for agriculture, forestry, and the household, beetles can be considered pests.
Some ant species are considered as pests. The presence of ants can be undesirable in places meant to be sterile. They can also come in the way of humans by their habit of raiding stored food, damaging indoor structures, causing damage to agricultural crops either directly or by aiding sucking pests or because of their stings and bites.
Bed Bugs are parasitic insects that feed exclusively on blood. Bed Bugs can cause a number of health effects, including skin rashes, psychological effects, and allergic symptoms. Bed bug infestations resurged since the 1980s.