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Thrips: Order Thysanoptera

Thrips (Order Thysanoptera) are tiny, slender insects with fringed wings (thus the scientific name, from the Greek thysanos (fringe) + pteron (wing). Other common names for thrips include thunderflies, thunderbugs, storm flies, thunderblights, and corn lice.

Thrips species feed on a large variety of sources, both plant and animal.

Ponticulothrips diospyrosi on finger for scale.
Ponticulothrips diospyrosi on a finger for scale.

Thrips species feed on a large variety of sources, both plant and animal, by puncturing them and sucking up the contents.

A large number of thrips species are considered pests because they feed on plants with commercial value.

Some species of thrips feed on other insects or mites and are considered beneficial, while some feed on fungal spores or pollen. So far around 5,000 species have been described.

Thrips are generally tiny (1 mm long or less) and are not good flyers, although they can be carried long distances by the wind.

In the right conditions, many species can exponentially increase in population size and form large swarms, making them an irritation to humans.

Like the words sheep, deer or moose, the word thrips is used for both the singular and plural forms, so there may be many thrips or a single thrips. The word thrips is from the Greek, meaning “wood louse”.

Characteristics

They are small hemimetabolic insects with a distinctive cigar-shaped bauplan, elongated with transversely constricted bodies. They range in size from 0.5 to 14 millimetres (0.020 to 0.55 in) in length for the larger predatory thrips, but most thrips are about 1 mm in length. Flight-capable thrips have two similar, strap-like, pairs of wings with a ciliated fringe, from which the order derives its name. Their legs usually end in two tarsal segments with a bladder-like structure known as an arolium at the pretarsus. This structure can be everted by means of hemolymph pressure, enabling the insect to walk on vertical surfaces.

Thrips have asymmetrical mouthparts that are also unique to the group. Unlike the Hemiptera, the right mandible of thrips is reduced and vestigial – and in some species completely absent. The left mandible is larger and forms a narrow stylet used to pierce the cell wall of tissues.[5] Some species may then inject digestive enzymes as the maxillary stylets and hypopharynx are inserted into the opening to drain cellular fluids. This process leaves a distinctive silvery or bronze scarring on the surfaces of the stems or leaves where the thrips feed.

Thysanoptera is divided into two suborders: Terebrantia, and Tubulifera; these can be distinguished by morphological, behavioral, and developmental characteristics. Members of Tubulifera 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 eight families of the Terebrantia all possess the eponymous saw-like ovipositor on the anteapical abdominal segment, lay eggs singly within plant tissue, and have two “pupal” stages.

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From Wikipedia, the free encyclopaedia

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