ABSTRACT

Australian gall–forming thrips and their allies comprise a group of several dozen species with a remarkable range of life histories and social systems. These species can be categorized into six ecological modes: (1) gall–formers on Acacia, which include species of Oncothrips, Kladothrips and Onychothrips in which galls are initiated by a single female, or a male and a female; (2) kleptoparasites in the genus Koptothrips, which usurp galls, kill the gall–formers, and breed inside; (3) opportunistic gall–inhabitants, such as some Warithrips, Grypothrips and Csirothrips, which breed in abandoned galls after the original inhabitants have left; (4) domicile–formers in the genera Lichanothrips, Panoplothrips, Dunatothrips and Carcinothrips, which either glue phyllodes (petioles modified as leaves) together and live inside, or use a cellophane–like material to create an enclosed space containing multiple apical Acacia phyllodes; (5) lepidopteran leaf–tie inhabitants, Warithrips, which live in phyllodes tied by lepidopteran silk; and (6) pre–existing hole inhabitatants, species of Dactylothrips and Katothrips that live in old Hymenoptera galls, abandoned leaf mines, or holes in split–stem galls. Social behavior of these Australian thrips include soldier castes in four species of Oncothrips and two species of Kladothrips, a wingless, apparently non–soldier morph in Oncothrips sterni, pleometrotic (multiple– adult) colony founding in species of Katothrips, Dunatothrips, and Lichanothrips, and group foraging in a Lichanothrips.