Thrips (Thysanoptera)
|
parlour palm thrips, Parthenothrips dracaenae, adult female; Photo © Miroslav Deml, www.biolib.cz/en/ |
|
greenhouse thrips, Heliothrips haemorrhoidalis, adult female; Photo by Cheryle O'Donnell, USDA-APHIS-PPQ |
|
parlour palm thrips, Parthenothrips dracaenae, adult female, lateral view; Photo © Miroslav Deml, www.biolib.cz/en/
|
|
greenhouse thrips, Heliothrips haemorrhoidalis, adult females; Photo by Lyle Buss, University of Florida |
|
Parthenothrips dracaenae, slide-mounted adult female; Photo courtesy of Hoddle, Mound, and Paris, 2008, Thrips of California |
|
Heliothrips haemorrhoidalis, adult female; Photo courtesy of Hoddle, Mound, and Paris, 2008, Thrips of California |
|
lower surface of Veitchia sp. leaf damaged by thrips feeding; Photo by T.K. Broschat, University of Florida, IFAS/FLREC |
|
upper surface of Veitchia sp. leaf damaged by thrips feeding; Photo by T.K. Broschat, University of Florida, IFAS/FLREC |
Rank & taxon
Order Thysanoptera
Description
Adult: Thrips are small (may reach a length of 12 mm), slender insects with fringes on the margins of both pairs of their long, narrow wings. They feed by puncturing their host and sucking out the cell contents. Thrips differ from all other insects in the form of the mouth parts. The mouth parts are asymmetric, with only the left mandible functional in larvae and adults. Most thrips range in color from translucent white or yellowish to dark brown or blackish.
Larvae: Thrips immatures are similar in shape to adults, with a long, narrow abdomen, but lacking wings.
Distribution
Worldwide, almost 6,000 species of Thysanoptera are recognized in nearly 800 genera.
Biology/life cycle
Thrips are hemimetaboloushemimetabolous:
with simple metamorphosis from egg to nymph stages to adult, lacking a true pupal stage (usually just a series of molts)
, passing through a pupal-like stage where they become primarily sedentary and do not feed. The rate at which thrips move through their life cycle is highly dependent on environmental conditions, including temperature and the quality of the available food source. Very tiny eggs (about 0.2mm long and kidney-shaped) hatch anywhere from a day to several weeks after being laid. Thrips go through two nymphal instars prior to their pupal-like stage. The suborder Terebrantia has one pupal stage whereas the suborder Tubulifera has two. During this stage, the wing buds and reproductive structures grow and mature, and the insect emerges in its adult form. All described genera of thrips are capable of parthenogenesisparthenogenesis:
the production of offspring without mating - eggs develop normally without being fertilized
, and some species are known only from the female sex.
Thrips are mainly plant feeders, sucking up fluids from leaves, flowers, and fruits, though same may feed on pollen, fungal spores, or are predatory. Many thrips (mainly in the Thripidae) are pests of agricultural and horticultural crops. Phytophagousphytophagous:
feeding upon plant matter
thrips typically congregate on the abaxial surfaces of the palm leaves. The immatures feed by rasping the surface tissues and sucking the juices released by the plant. This causes stippling and silvering on the leaves. The silvered areas where they have fed are peppered with shiny black dots of their excrement.
Hosts
Palms: a wide variety of palms
Other: a wide variety of plants
Representative taxa on palms
Nearly all of the world's pest species on palms occur in the family Thripidae. Two thrips species can be found on palms in North America.
Heliothrips haemorrhoidalis is widespread in Europe, North America, South America, Australia, Africa, and Asia. This species is probably the most common thrips that damages palm foliage.
Parthenothrips dracaenae is widespread through the tropics and common on indoor ornamental plams.
Additional comments
The common name, thrips, is singular and plural.
Thrips are more likely to damage palms in interiorscapes and in nurseries than in landscape situations.
Species identification requires at least a dissecting microscope with 40x magnification. Often, slide mounted specimens are required for verification.
