Thripidae: Thripinae

Biology

Members of this subfamily exhibit a wide range of biologies. Many species live in flowers, others live only on leaves, and some species live in both habitats, particularly the pest species. Several of the pest species, such as Frankliniella occidentalis and Thrips tabaci, are also facultative predators on mites, and can thus be beneficials, but few species apart from the members of Scolothrips are known as obligate predators. One group of species seem likely to be involved in gall-induction on plants in S.E. Asia and Australia (Tree & Mound, 2009). There are several major radiations of Thripinae on Poaceae, either in the floral parts or on leaves, and species of the genus Chirothrips are known to pupate within the glumes and thus become distributed in grass seed. In contrast, there are only a few other examples of radiations in association with particular families of flowering plants, such as Fabaceae and Orchidaceae.

Diversity

There is great diversity among Thripinae in colour and structure, and there is no satisfactory supra-generic or tribal classification. Several "genus-groups" have been distinguished, including the Scirtothrips group, the Trichromothrips group, the Mycterothrips group, the Frankliniella group and the Thrips group (Masumoto & Okajima, 2005, 2006, 2007; Mound, 2002). Groups based on the loss of, or reduction in length of, major setae are not likely to have any phylogenetic significance (Mound & Masumoto, 2009). More than 1700 species in over 220 genera are listed in this subfamily, but the only reliable identification systems are regional, not global. The number of antennal segments varies from 6 to 9, the pronotum may have no long setae or bear as many as six pairs of very long setae, and similarly the forewings may have few and inconspicuous setae or complete rows of prominent setae on both longitudinal veins.

Distribution

As with all Thysanoptera groups, most genera and species of Thripinae are found in the tropics and subtropics. Despite this, there is a major radiation of Thrips and Chirothrips in the northern temperate zone, and a major radiation of Anaphothrips in Australia. Warm arid zones have a considerable thripine fauna (Bhatti, et al., 2003), but there are only a few species that live in colder regions, such as Ceratothrips ericae in Greenland, Frankliniella antarctica on Kerguelen Island, and Physemothrips chrysodermus on Macquerie Island. Some genera have restricted patterns of radiation such as, in the New World Arorathrips, Psectrothrips, Pseudothrips, and even Frankliniella, in Australia Odontothripiella and Pseudanaphothrips, and in Asia Chaetanaphothrips. Other genera are more widespread, although even the worldwide genus Thrips has no species native to South America.

Subfamilies A-Z