Abdominal armature and the systematics of Xaniothrips species (Thysanoptera : Phlaeothripidae), kleptoparasites of domicile-producing thrips on Australian Acacia trees

Species of the genus Xaniothrips Mound live as kleptoparasites within domic iles produced by other thrips on the phyllodes of Various Acacia trees in t he Eremaean zone of Australia. Females of each of these thrips species have an array of very stout spines on the abdomen, and in two of them the anal area is asymmetric and directed dorsally, bearing two pairs of stout setae. The lateral abdominal armature has arisen by multiplication of the plesiot ypic setal pattern of the sternites. Observations suggest that members of t his genus use their armature to expel a resident thrips from its domicile o f tied or glued phyllodes, and then to defend this living space from other intruders. Seven species are now recognised in the genus, of which the foll owing five are described as new species: X. eremus, X. foederatus, X. mulga , X. rhodopus and X. zophus. Three of these are associated with Acacia aneu ra, whereas the two previously known species, X. leukandrus Mound and X. xa ntes Mound, are associated with A. harpophylla. However, some evidence sugg ests that X. xantes may exist as two or more host-specific forms on other A cacia species. Four of the Xaniothrips are associated with phyllode glues p roduced by Dunatothrips spp., whereas X. foederatus, X. leukandrus and X. x antes are associated with phyllode glues produced by Lichanothrips spp.