Morphological and electrophoretic taxonomy of the Australian eucalypt leaf-blister sawfly genus Phylacteophaga (Hymenoptera: Pergidae): a potential major pest group of eucalypts worldwide

Abstract

The taxonomic status of Phylacteophaga Froggatt is re-evaluated using the independent techniques of allozyme electrophoresis and detailed morphological comparison. Analysis of 45 scorable loci showed highly significant fixed differences (46–51%) among two currently recognized subspecies, P. eucalypti eucalypti Froggatt P. e. froggatti Riek, and a previously unrecognized taxon from Tasmania, demonstrating that they are different species. In addition to colour, significant variation is revealed among P. e. occidens Benson, P. rubida Riek and the three electrophoretically defined species, in body size, structure of the antennae, the shape of the crest, dorsal spines and saw teeth of the ovipositor, and in male genitalia. Based on these results there is substantial justification in recognizing P. occidens and P. rubida as separate species, distinct from P. eucalypti, P. froggatti, and P. amygdalini sp. n. Further, comparison of the holotype of P. e. tasmanica Riek shows it to be conspecific with the lectotype of P. eucalypti (designated here) so that the former species is considered a junior synonym. The distribution of P. eucalypti and P. froggatti is extended to include Tasmania, and a key is presented to distinguish the males and females of all five species. The biology and host plant relations of the species concerned are discussed, along with their pest status and potential to spread to other regions of the world where eucalypts are grown.