Journal article

Distribution and rapid range expansion of the introduced willow sawfly Nematus oligospilus Forster (Hymenoptera: Tenthredinidae) in Australasia

Valerie Caron, Fiona Ede, Paul Sunnucks, Dennis J O'Dowd



The willow sawfly, Nematus oligospilusFörster (Hymenoptera: Tenthredinidae), has been introduced inadvertently across temperate regions in the Southern Hemisphere, including New Zealand and Australia, where it has dispersed extremely rapidly. A host specialist herbivore, at high population densities it can defoliate and damage introduced willows (Salix spp.), many species of which are invasive weeds in Australasia. In this study, we show that in just 10 years, the distribution of N.oligospilus has expanded across most of south-eastern Australia and south-western Western Australia and, in less than 15 years across both the North and South Islands of New Zealand. The relative population densit..

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University of Melbourne Researchers


Funding Acknowledgements

We thank A Flynn for presence data from New Zealand. We also thank G Perdomo, T Hunt and D Clements for field assistance, R Thompson for useful discussions and two anonymous reviewers. This work was funded by Holsworth Wildlife Endowment, Melbourne Water, North Central Catchment Management Authority, North East Catchment Management Authority, West Gippsland Catchment Management Authority and the Victorian Department of Primary Industries Nancy Millis Postgraduate Award to V.C.