chilli thrips; photo by Lyle Buss, Department of Entomology and Nematology, University of Florida. Thrips are economically important since some species transmit plant viruses. (Ed.) They range in color from black to dark brown to tan to yellowish. Fundamentals of Entomology: A manual for introductory courses. Other species are primitively eusocial and form plant galls and still others are predatory on mites and other thrips. The bristles (setae) of some are expanded at the tips or elongated, or the body wall may be expanded into prongs or forks. Although similar in overall form to the adult, the larvae of thrips are smaller and simpler in structure. Thrips (order Thysanoptera) are minute (mostly 1mm long or less), slender insects with fringed wings and unique asymmetrical mouthparts. The fourth or fifth instar, the "pupa," is sometimes enclosed in a cocoon. [52][53][54], Most insects create lift by the stiff-winged mechanism of insect flight with steady state aerodynamics; this creates a leading edge vortex continuously as the wing moves. in length. Animal biodiversity: An outline of higher-level classification and survey of taxonomic richness", "Homologies and Host-Plant Specificity: Recurrent Problems in the Study of Thrips", "Molecular Identification Key for Pest Species of Scirtothrips (Thysanoptera: Thripidae)", "Egg predation within the nests of social wasps: a new genus and species of Phlaeothripidae, and evolutionary consequences of Thysanoptera invasive behaviour", "Pollination and gene flow in chillies with. Biological insecticides such as the fungi Beauveria bassiana and Verticillium lecanii can kill thrips at all life-cycle stages. [67] Over 20 plant-infecting viruses are known to be transmitted by thrips, but perversely, less than a dozen of the described species are known to vector tospoviruses. In 1836 the Irish entomologist Alexander Henry Haliday described 41 species in 11 genera and proposed the order name of Thysanoptera. Tarsi 1-2 segmented, with eversible adhesive bladders apically. The western flower thrips, Frankliniella occidentalis, has spread until it now has a worldwide distribution, and is the primary vector of plant diseases caused by tospoviruses. while others are predatory. Characteristics [37] Thrips are likewise the primary pollinators of heathers in the family Ericaceae,[38] and play a significant role in the pollination of pointleaf manzanita. They prefer tender parts of the plant, such as buds, flowers and new leaves. These insects got through a kind of metamorphosis that is intermediate between simple (or gradual) and complete. Females of the suborder Terebrantia cut slits in plant tissue with their ovipositor, and insert their eggs, one per slit. A few species serve as vectors for over 20 viruses that cause plant disease, especially the Tospoviruses. Weeks, and A.C. Hodges. [8][9][10], Thrips are small hemimetabolic insects with a distinctive cigar-shaped body plan. Thrips are able to walk on glassy smooth surfaces because they have an eversible adhesive pad located on the tip of each foot, between the claws. Let us know if you have suggestions to improve this article (requires login). The internal relationships from these analyses are shown in the cladogram. In addition, they feed on onions, carrots, melons, cucumbers, peas, beans, roses, gladiolus, irises, and mullein. The egg stage is followed by two larval stages, during which all the immature feeding occurs. Leaves may curl upwards and appear brittle. Distribution:Common inhabitants of flowers, leaf litter, and fungi throughout the world. By the Early Cretaceous, true thrips became much more abundant. 
Thrips setipennis is the sole pollinator of Wilkiea huegeliana, a small, unisexual annually flowering tree or shrub in the rainforests of eastern Australia. Small males may sneak in to mate while the larger males are busy fighting. Suitable predators must be small and slender enough to penetrate the crevices where thrips hide while feeding, and they must also prey extensively on eggs and larvae to be effective. Wind-aided dispersal of species has been recorded over 1600km of sea between Australia and South Island of New Zealand. Please refer to the appropriate style manual or other sources if you have any questions. Although larvae are generally found in shady locations, on the underside of leaves or branches, adults occasionally occur on the upper side of leaves in bright light. [13], Many thrips form galls on plants when feeding or laying their eggs. Some species of thrips are beneficial as pollinators or as predators of other insects or mites. Some species that live in litter eat fungi or decaying plant materials. See individual fact sheets for more detailed information. American Biological Supply Company. The The mouthparts consist of a single stylet on the mandible and two stylets on the maxilla. a wide variety of plant species, both native and introduced. Thrips feeding cause flowers, petals, pistils, and stamens to appear bronzed and brittle. Most of these species occur in the tropics and sub-tropics, and the structures of the galls are diagnostic of the species involved. Males fight by flicking their rivals away with their abdomen, and may kill with their foretarsal teeth. [5][6][7] The older group name "physopoda" is with reference to the bladder like tips to the tarsi of the legs. Most species feed on plant tissues (often in flower heads), but some are predators of mites and various small insects (including other thrips). In the tropics, many thrips are more active in the wet than in the dry seasons. These may occur as curls, rolls or folds, or as alterations to the expansion of tissues causing distortion to leaf blades. (Eucalyptus thrips). T. setipennis serves as an obligate pollinator for other Australian rainforest plant species, including Myrsine howittiana and M. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. [11][12] They have compound eyes consisting of a small number of ommatidia and three ocelli or simple eyes on the head. Thrips puncture the fruit epidermis, leaving a characteristic scarring in the form of a grey ring. Thrips have been known to bite. Eaton, E. and K. Kaufman. BioKIDS home|Questions?|Animal Diversity Web|Cybertracker Tools. Most thrips rest tightly against leaf veins or in crevices. The presence of dark-coloured spots of excreta adjacent to light-coloured feeding zones are some typical signs of thrips damage. The word "thrips" is both singular and plural. [39] This impact may fall across a broad selection of prey items, as there is considerable breadth in host affinity across the order, and even within a species, varying degrees of fidelity to a host. [63][66], Many thrips are pests of commercial crops due to the damage they cause by feeding on developing flowers or vegetables, causing discoloration, deformities, and reduced marketability of the crop. Some of the gall-forming Phlaeothripidae, such as genera Kladothrips[50] and Oncothrips,[51] form eusocial groups similar to ant colonies, with reproductive queens and nonreproductive soldier castes. There may be one, two, or three pupal stages in which no feeding occurs. "Minute pollinators: The role of thrips (Thysanoptera) as pollinators of pointleaf manzanita, "Ecology and evolution of social behaviour among Australian gall thrips and their allies", "Quick estimates of flight fitness in hovering animals, including novel mechanisms for lift production", "Meniscus ascent by thrips (Thysanoptera)", "Western Flower Thrips, Management and Tospoviruses", "Evolution of asexuality via different mechanisms in grass thrips (Thysanoptera: Aptinothrips)", "Egg sizemediated sex allocation and matingregulated reproductive investment in a haplodiploid thrips species", "The thrips, or Thysanoptera, of Illinois", "A review of thrips species biting man including records in Florida and Georgia between 19861997", 10.1653/0015-4040(2005)88[447:AROTSB]2.0.CO;2, "Western flower thrips in greenhouses: a review of its biological control and other methods", "Efficacy of red LED irradiation for controlling, Thrips images from the "Pests and Diseases Image Library (PaDIL)" of Australia, University of California Pest Management Guidelines for Thrips, University of California Thrips Identification, https://en.wikipedia.org/w/index.php?title=Thrips&oldid=1098512027, Articles containing Ancient Greek (to 1453)-language text, Creative Commons Attribution-ShareAlike License 3.0, Black circle and heavy line: wing (rachis and bristles); Black (curved) arrows: flow; Blue arrows: induced velocity; Orange arrows: net force on wing, CISR: Center for Invasive Species Research Fact Sheets, This page was last edited on 16 July 2022, at 05:12. [60], Thrips are hemimetabolous, metamorphosing gradually to the adult form. are widely distributed throughout Australia and can be found on thrips, (order Thysanoptera), any of approximately 5,000 species of insects that are among the smallest of the winged insects and are abundant in the tropical and temperate regions of the world. In some species, the third or fourth instar, the "prepupa," has external wings, but is inactive and does not feed. [69] Other viruses that they spread include the genera Ilarvirus, (Alpha|Beta|Gamma)carmovirus, Sobemovirus and Machlomovirus. From 1900 to 1920, tug-of-war was an official event at the Summer Olympics. The abdomen consists of eleven segments, whereby ten segments are visible. During the first two instars, nymphs can feed on the leaves, foliage, or young fruit. They consume flower heads of daisies and dandelions. Without additional evidence to support a phylogenetic link to the Holometabola, it would appear that this "pupal stage" may be nothing more than a curious coincidence of convergent evolution. All rights reserved. Please select which sections you would like to print: Get a Britannica Premium subscription and gain access to exclusive content. The eggs of the hosts including Mischocyttarus atramentarius, Mischocyttarus cassununga and Polistes versicolor are eaten by the thrips. Thrips are found in flower blossoms, on the undersides of leaves, in leaf whorls and axils, under bark, in mosses, in leaf litter and soil, on fungi, and on fruits and flower bulbs. It is commercially available or can be made of certain types of household soap. Feeding activities result in plant deformities, scarring, loss of yield, and in some cases, transmission of plant pathogens. Wings are either translucent or have light and dark banding. Several thrips have all citrus species and their hybrids listed as hosts, including the chilli thrips, citrus thrips, Florida flower thrips, greenhouse thrips, and South African bean thrips. citrus thrips; photo by Joseph Morse, University of California, Riverside, www.bugguide.net, Florida flower thrips; photo by Lyle Buss, Department of Entomology and Nematology, University of Florida, greenhouse thrips; photo by Lyle Buss, Department of Entomology and Nematology, University of Florida, South African bean thrips; photo courtesy of Queensland Government Primary Industries and Fisheries, New Zealand, Citrus PestsContent last updated June, 2012idtools.org. The feathery wings of thrips, however, generate lift by clap and fling, a mechanism discovered by the Danish zoologist Torkel Weis-Fogh in 1973. variabilis. Tubulifera consists of a single family, Phlaeothripidae; members can be identified by their characteristic tube-shaped apical abdominal segment, egg-laying atop the surface of leaves, and three "pupal" stages. Females of the suborder Tubulifera lay their eggs singly or in small groups on the outside surfaces of plants. Heavy infestations can lead to flower drop. The long anal bristles characteristic of larvae may hold droplets of excreted liquid that are deposited on leaf surfaces. However, heavy rains, winds, and dust are probably as destructive to thrips as are predators. Others are gall inducers. The trailing edge vortices, however, cancel each other out with opposing flows. Thrips in the suborder Terebrantia always lay eggs, as do most thrips in the more advanced suborder Tubulifera. Thrips feeding turns leaves bronze or silver. After this, the adult results. Antennae are either monochrome or have grey to yellow alternating bands. [19], The phylogeny of thrips families has been little studied. [62] Thrips can survive the winter as adults or through egg or pupal diapause. [3][1], The generic and English name thrips is a direct transliteration of the ancient Greek , thrips, meaning "woodworm". Flight-capable thrips have two similar, strap-like pairs of wings with a fringe of bristles. flowers of a wide variety of plants. 333- 335. Females of the eight families of the Terebrantia all possess the eponymous saw-like (see terebra) ovipositor on the anteapical abdominal segment, lay eggs singly within plant tissue, and have two "pupal" stages. The legs are short and have a retractile bladderlike organ. Last Updated: 23 January 2020, incomplete development (egg, nymph, adult), closely related to Hemiptera and Psocoptera. More than 100 species inhabit the Great Lakes region. [55][56][57][58], Clap 2: leading edges touch, wing rotates around leading edge, vortices form, Clap 3: trailing edges close, vortices shed, wings close giving thrust, Fling 1: wings rotate around trailing edge to fling apart, Fling 2: leading edge moves away, air rushes in, increasing lift, Fling 3: new vortex forms at leading edge, trailing edge vortices cancel each other, perhaps helping flow to grow faster (Weis-Fogh 1973), Apart from active flight, thrips, even wingless ones, can also be picked up by winds and transferred long distances. [60] The adult stage can be reached in around 815 days; adults can live for around 45 days. This developmental stage, usually called a "pupa", has aroused a great deal of speculation by some entomologists who claim that thrips represent an "intermediate" stage between hemi- and holometabolous development. On the other hand, a few species prey on destructive mites and scale insects, and a number may aid in the pollination of flowers. Pupae can be found on leaves, soil, or under the calyx. Several species develop either external or internal wings during the first two. They range in size from 0.5 to 14mm (0.02 to 0.55in) in length for the larger predatory thrips, but most thrips are about 1mm in length. species also occur in leaf litter or under the bark of trees. Thrips have small or large compound eyes, and three ocelli are present in fully winged forms. Many thrips cause damage to important crops of vegetables, fruits, and flowers. tissue or scattered where the female is feeding. Their identification to species by standard morphological characteristics is often challenging. Triplehorn, C. and N. Johnson. Some species have red eyes that fade closer to maturity. The right mandible disappears during embryogenesis. Many species are secondarily wingless. There is also considerable variability leading to many species being misidentified. Many thrips are destructive pests of plants, especially grain crops, fruits and vegetables, and ornamentals. Hatching of eggs within the female (ovoviparity), occurs in some highly evolved members of the Tubulifera. Many thrips species are pests of commercially important crops. In the clap part of the cycle, the wings approach each other over the insect's back, creating a circulation of air which sets up vortices and generates useful forces on the wings. Their wings, when present, are narrow and fringed, hence the name Thysanoptera (Latin for fringed wings). Corrections? After emergence, adults resume feeding by lancing a plant cell and sucking in exuded plant fluids. The largest recorded phlaeothripid species is about 14 mm long. Thrips The first monograph on the group was published in 1895 by Heinrich Uzel who is considered the father of Thysanoptera studies. The wings are folded back over the body at rest. In Tubulifera, the Phlaeothripidae and its subfamily Idolothripinae are monophyletic. There are some species of thrips that feed on mites, small insect larvae, and other species of thrips. When present, the wings are slender and rod-like with a dense fringe of long hairs. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.Copyright 2002-2022, The Regents of the University of Michigan. [73], Due to their small sizes and high rates of reproduction, thrips are difficult to control using classical biological control. These live among leaf litter or on dead wood and are important members of the ecosystem, their diet often being supplemented with pollen. The wings close, expelling air from between them, giving more useful thrust. 
Unlike the Hemiptera (true bugs), the right mandible of thrips is reduced and vestigial and in some species completely absent. Belmonte, California. [46] Anal secretions are produced in the hindgut,[47] and released along the posterior setae as predator deterrents[47][48] In Australia, aggregations of male common blossom thrips have been observed on the petals of Hibiscus rosa-sinensis and Gossypium hirsutum; females were attracted to these groups so it seems likely that the males were producing pheromones. [32][33][34] Darwin found that thrips could not be kept out by any netting when he conducted experiments by keeping away larger pollinators. [4] Like some other animal names such as sheep, deer, and moose, in English the word thrips is both the singular and plural forms, so there may be many thrips or a single thrips. Thrips can be easily mistaken for small insects such as aphids and psyllids. [13], Thrips have asymmetrical mouthparts unique to the group. The prepupal stage lasts only a few hours to several days and gives rise to the final pupal stage, which may be of short or long duration. In addition, when there is a proliferation in the numbers of thrips in the Great Lakes region, these insects may cause respiratory and skin irritation to agricultural workers. Thrips are found worldwide. Their legs usually end in two tarsal segments with a bladder-like structure known as an "arolium" at the pretarsus. stage before becoming fully reproductive adults. The leading edges of the wings touch, and the wings rotate around their leading edges, bringing them together in the "clap". [27], Most research has focused on thrips species that feed on economically significant crops. [28][29] Besides feeding on plant tissues, the common blossom thrips feeds on pollen grains and on the eggs of mites. Swedish entomologist Baron Charles De Geer described two species in the genus Physapus in 1744 and Linnaeus in 1746 added a third species and named this group of insects Thrips. In the Merothripidae and in the Aeolothripidae, males are again polymorphic with large and small forms, and probably also compete for mates, so the strategy may well be ancestral among the Thysanoptera. Front and hind wings slender, rod-like, with a dense fringe of long hairs. Evolution, paleontology, and classification. [63] In Pezothrips kellyanus females hatch from larger eggs than males, possibly because they are more likely to be fertilized. In the Phlaeothripidae, the males are often larger than females and a range of sizes may be found within a population. Houghton Mifflin Company. Thrips may leave excrement (frass) in the form of brown dotting on the undersides of leaves. Although no species feed on blood and no known animal disease is transmitted by thrips, some skin irritation has been described. Thrips are primarily phytophages; that is, they eat plants and parts of plants, such as pollen, flowers, leaves, fruits, twigs, or buds. The first recorded mention of thrips is from the 17th century and a sketch was made by Philippo Bonanni, a Catholic priest, in 1691. Forewings and hindwings are similar. [17] There are currently over six thousand species of thrips recognized, grouped into 777 extant and sixty fossil genera. begin to feed immediately on the plant beside their parents. Premature fruit drop can occur during heavy infestations. A close examination of the thysanopteran "pupa", however, reveals that it does not undergo any internal transformation. [29][43], Some species of thrips create galls, almost always in leaf tissue. 
[13], Thrips are haplodiploid with haploid males (from unfertilised eggs, as in Hymenoptera) and diploid females capable of parthenogenesis (reproducing without fertilisation), many species using arrhenotoky, a few using thelytoky. [49], In the phlaeothripids that feed on fungi, males compete to protect and mate with females, and then defend the egg-mass.
Although Thysanoptera are hemimetabolous, many species undergo an extended metamorphosis in which the final immature stage is quiescent, non-feeding, and sometimes even enclosed in a silken cocoon. The primary method of reproduction among thrips is by bisexual union. Other biocontrol agents of adults and larvae include anthocorid bugs of genus Orius, and phytoseiid mites. Adults have extensible bladders on the tarsi of the legs, as suggested by the common name bladder feet. [36] The genus Cycadothrips is a specialist pollinator of cycads, the cones of which are adapted for pollination by small insects. develop through a few stages before they undergo a pre-pupal (Hemiptera) with similar sucking mouthparts but can be Legs are either white to yellow or have light and dark banding. Because of their minute size, they can enter the smallest flowers or tiniest cracks in stems and bark. They are narrow and have a setal fringe. The first two instars, called larvae or nymphs, are like small wingless adults (often confused with springtails) without genitalia; these feed on plant tissue. A preliminary analysis in 2013 of 37 species using 3 genes, as well as a phylogeny based on ribosomal DNA and three proteins in 2012, supports the monophyly of the two suborders, Tubulifera and Terebrantia. There are approximately 5000 species. In Terebrantia, Melanothripidae may be sister to all other families, but other relationships remain unclear.
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