Thrips of Australia

Taxonomic Studies on Australian thrips

Only one native Australian thrips species was named before 1900, the Giant Thrips, Idolothrips spectrum, apparently from specimens collected by Charles Darwin. By 1915 less than 20 thrips species were known from Australia, and most of these had come from Europe. In the following ten years more than 100 species were named, and between 1926 and 1929 over 160 additional species were described, although many of these are now placed in synonymy. The final wave of descriptive activity from the first half of the century was published posthumously in 1968 from Dudley Moulton of California (1878–1951); of the 20 new species included, eight are now placed in synonymy, and a further eight allocated to different genera. Up until the 1960s, studies on thrips in Australia were focused sharply onto one or other of two separate disciplines, with little interdisciplinary communication. One focus produced a series of ecological studies on the Plague Thrips, Thrips imaginis (Andrewartha, 1934; Evans, 1935). The other produced descriptive taxonomic papers that were largely devoid of biological observations, and were often superficial even by the descriptive standards of the period. A.A. Girault made available 139 species-group names for Australian thrips in a series of privately published, un-illustrated, notes that were as remarkable for their outrageously expressed opinions on a wide range of topics as they were for their lack of descriptive detail (Gordh et al., 1979). His slide preparations are exceptionally poor, often with specimens of different species under one cover-glass, and with a surprising number of these cover-glasses broken; also, the labels are poorly written and sometimes misleading. He appears to have recognised species largely from colour, rather than from structural details. For example, the specimens Girault labelled as Thrips lacteicorpus involve pale individuals of three species, Thrips australis, T. imaginis and T. tabaci. Although employed at one time to study the biology and control of banana thrips, his descriptive taxonomy was based largely on single specimens with no biological information. Consequently, 77 of the 139 thrips species he described are now placed in synonymy. Taxonomists in the Northern Hemisphere similarly produced a high rate of synonymy when describing Australian species, because intra-specific variation in colour and structure was not recognised. The number of Australian species-group names erected by each of the major authors, together with the percentage of those names currently placed as synonyms, is: Girault 139 (55%); Bagnall 63 (33%); Karny 40 (42%); Hood 47 (17%); and Moulton 39 (33%).