Thysanoptera (thrips)

Thysanoptera fast facts

  • Minute, slender bodies.
  • Most are only a few mm long. The largest, Idolothrips spectrum, an Australian species, is 12 mm long and was discovered by Charles Darwin. Largest British species is 7 mm long.
  • Short antennae.
  • Mouthparts stylet-like and asymmetrical, but require a microscope to be examined.
  • 2 pairs of equal-sized wings narrow with long hair fringes around the entire margins and reduced venation.
  • Some species wingless.
  • Legs terminate in adhesive pads.
  • Though to be most closely related to the Hemiptera (bugs).
  • About 6,000 described worldwide, over 570 in Europe, 179 in British Isles.
  • Fossil record goes as far back as the Triassic.
  • Greek thysanos = fringe, pteron = wing.
  • Sometimes called thunder flies as they tend to be more active in hot, thundery weather.

Thrips is both singular and plural.

The adult thrips (see drawing below) are usually brown or black and are commonly found in flowers. They are not usually active in winter. The easiest way to find one is to pull a dandelion flower apart over white paper or a white tray.

Most adults feed by piercing plant cells and sucking the sap. Some live on fungi, and a few suck the juices of other insects. Some species can be crop pests, e.g. onion thrips (Thrips tabaci) and grain thrips (Limothrip cerealium) and they can transmit diseases between plants, but they do also pollinate the flowers they visit.

The wings are coupled together by hooks on the hind wing. Some species are wingless, and some have short non-functional wings. Even within a species the wing development can vary.

Thysanoptera, thrips, adult

Mouthparts. Thrips have very unusual mouthparts. Only the left mandible (jaw) is present, and it is formed into a piercing needle to push into the food source. The liquid food is sucked up through a narrow tube formed by the 2 maxillae. The fungal and predatory species have slightly different mouthparts, but the right mandible is missing in all species.

Eggs are usually laid on plants, and some females have a saw-like ovipositor that enables them to place their eggs in the plant. The eggs hatch in 2 - 20 days depending on the species.

The larva resemble the adults, but do not have wings. On hatching they suck plant sap. Later some may become carnivorous. They pupate in soil or leaf litter.

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