Barklice, Booklice, and Parasitic Lice
order of class “Insects“
1 order, 2 species
Psocids are small insects that feed on fungi, algae, and detritus, with some species also consuming household items like grains and book bindings. They have chewing mandibles, large compound eyes, and can spin silk from glands in their mouth. Psocids can lay eggs in crevices or on foliage, and their young go through multiple molts before reaching adulthood. Some species of psocids can be pests of stored products, but most are woodland insects with little interaction with humans. Psocids play a role in ecosystems by aiding in decomposition and some species can bore into wood to create habitats for other organisms.
Hierarchy
species of infraorder “Barklice, Booklice, and Parasitic Lice“
1 species
Anatomy and biology#
Psocids are small, scavenging insects with a relatively generalized body plan. They feed primarily on fungi, algae, lichen, and organic detritus in nature but are also known to feed on starch-based household items like grains, wallpaper glue and book bindings. They have chewing mandibles, and the central lobe of the maxilla is modified into a slender rod. This rod is used to brace the insect while it scrapes up detritus with its mandibles. They also have a swollen forehead, large compound eyes, and three ocelli. Their bodies are soft with a segmented abdomen. Some species can spin silk from glands in their mouth. They may festoon large sections of trunk and branches in dense swathes of silk. Some psocids have small ovipositors that are up to 1.5 times as long as the hindwings, and all four wings have a relatively simple venation pattern, with few cross-veins. The wings, if present, are held tent-like over the body. The legs are slender and adapted for jumping, rather than gripping, as in the true lice. The abdomen has nine segments, and no cerci. There is often considerable variation in the appearance of individuals within the same species. Many have no wings or ovipositors, and may have a different shape to the thorax. Other, more subtle, variations are also known, such as changes to the development of the setae. The significance of such changes is uncertain, but their function appears to be different from similar variations in, for example, aphids. Like aphids, however, many psocids are parthenogenic, and the presence of males may even vary between different races of the same species. Psocids lay their eggs in minute crevices or on foliage, although a few species are known to be viviparous. The young are born as miniature, wingless versions of the adult. These nymphs typically molt six times before reaching full adulthood. The total lifespan of a psocid is rarely more than a few months. Booklice range from approximately 1 mm to 2 mm in length (1/25″ to 1/13″). Some species are wingless and they are easily mistaken for bedbug nymphs and vice versa. Booklouse eggs take two to four weeks to hatch and can reach adulthood approximately two months later. Adult booklice can live for six months. Besides damaging books, they also sometimes infest food storage areas, where they feed on dry, starchy materials. Although some psocids feed on starchy household products, the majority of psocids are woodland insects with little to no contact with humans, therefore they are of little economic importance. They are scavengers and do not bite humans. Psocids can affect the ecosystems in which they reside. Many psocids can affect decomposition by feeding on detritus, especially in environments with lower densities of predacious micro arthropods that may eat psocids. The nymph of a psocid species, Psilopsocus mimulus, is the first known wood-boring psocopteran. These nymphs make their own burrows in woody material, rather than inhabiting vacated, existing burrows. This boring activity can create habitats that other organisms may use.
Interaction with humans#
Some species of psocids, such as Liposcelis bostrychophila, are common pests of stored products. Psocids, among other arthropods, have been studied to develop new pest control techniques in food manufacturing. One study found that modified atmospheres during packing (MAP) helped to control the reoccurrence of pests during the manufacturing process and prevented further infestation in the final products that go to consumers.
External phylogeny#
Psocodea has been recovered as a monophyletic group in recent studies. Their next closest relatives are traditionally recognized as the monophyletic grouping Condylognatha that contains Hemiptera (true bugs) and Thysanoptera (thrips), which all combined form the group Paraneoptera. However, this is somewhat unclear, as analysis has shown that Psocodea could instead be the sister taxon to Holometabola, which would render Paraneoptera as paraphyletic. Here is a simple cladogram showing the traditional relationships with a monophyletic Paraneoptera:
Here is an alternative cladogram showing Paraneoptera as paraphyletic, with Psocodea as sister taxon to Holometabola:
Internal phylogeny#
Here is a cladogram showing the relationships within Psocodea:
Classification#
The order Psocodea (formerly ‘Psocoptera’) is divided into three extant suborders.
External links#
National Barkfly Recording Scheme Psoco Net Tree of Life: Psocodea Archipsocus nomas, a webbing barklouse on the UF / IFAS Featured Creatures Web site
Psocids are small insects that feed on fungi, algae, and detritus, with some species also consuming household items like grains and book bindings. They have chewing mandibles, large compound eyes, and can spin silk from glands in their mouth. Psocids can lay eggs in crevices or on foliage, and their young go through multiple molts before reaching adulthood. Some species of psocids can be pests of stored products, but most are woodland insects with little interaction with humans. Psocids play a role in ecosystems by aiding in decomposition and some species can bore into wood to create habitats for other organisms.
Ancestry Graph
Further Information
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