Natural history and description of Oncothrips kinchega, a new species of gall-inducing thrips with soldiers (Thysanoptera : Phlaeothripidae)

Abstract

A new species of gall-inducing thrips, Oncothrips kinchega sp. n., is described and its biology on the host plant Acacia carneorum was investigated. Our study showed that a single foundress initiates a gall. Her first-laid eggs develop into soldiers (mean number of soldiers ± SE = 28 ± 15, 40% males, with no evidence for protogyny or protandry). The soldiers, along with the foundress, produce the (subsequent) dispersing generation (mean number of dispersers ± SE = 187 ± 10, 37% males with no evidence for protogyny or protandry). The brood development-pattern of O. kinchega is similar to that found in the complex of forms currently referred to as Oncothrips habrus Mound and Oncothrips waterhousei Mound & Crespi and is different from that of Oncothrips morrisi Mound, Crespi & Kranz, a species with soldiers but a non-social development pattern. However, O. kinchega shares several life history characteristics with O. morrisi, and appears intermediate in brood size between O. morrisi and the remainder of the gall-inducers. The possible evolutionary significance of these observations is discussed.