Horistothrips Morgan

Mound, Laurence A., 2008, Identification and host associations of some Thysanoptera Phlaeothripinae described from Australia pre- 1930, Zootaxa 1714, pp. 41-60 : 42-43

Horistothrips Morgan

Horistothrips Morgan, 1913: 35 . Type-species H. australiae Morgan , by monotypy.

Aspidothrips Karny, 1920: 38 . Type-species A. platygaster Karny. Synonymised by Mound & Houston, 1987: 15.

The Australian species of Horistothrips are apparently fungal-hyphae feeders, living under the bark of dead trees. They are thus the ecological equivalent of species in the worldwide genera Hoplandrothrips Hood and Hoplothrips Amyot & Serville although, curiously, no substantial colonies of either Hoplothrips nor Horistothrips species have been found in Australia, despite much searching of apparently suitable habitats. Moreover, only one undescribed species of Horistothrips has been collected. Presumably, the aridity of the climate, together with predation by Australia’s ubiquitous ant and arachnid species, inhibits the development on this continent of the large sub-cortical populations of hyphal-feeding phlaeothripines that can be so common in Europe ( Mound et al., 1976).

Described as a monobasic genus, Horistothrips has come to include 10 nominal species. Seven of these are from Australia, of which five are here placed into synonymy. The systematic relationships of the genus are not clear, but in contrast to members of such genera as Hoplothrips and Hoplandrothrips in the Phlaeothrips - lineage of fungus feeders ( Mound & Marullo, 1996), the third antennal segment does not bear three sensoria. Instead, this segment has only a single sensorium, as in members of the leaf-feeding lineage of phlaeothripines related to Liothrips . The three non-Australian species listed in the genus have not been studied but, judging from their original descriptions, they seem unlikely to be closely related to the Australian species: Horistothrips claruspilus Moulton ( Fiji) ; Horistothrips magnafemora Moulton ( Fiji) ; Horistothrips palidispinosus Steinweden & Moulton ( China) .