Biological Invasions (2018) 20, 2395-2420

G. Dittrich-Schröder, T.B. Hoareau, B.P. Hurley, M.J. Wingfield, S. Lawson, H.F. Nahrung and B. Slippers (2018)
Population genetic analyses of complex global insect invasions in managed landscapes: a Leptocybe invasa (Hymenoptera) case study
Biological Invasions 20 (9), 2395-2420
Abstract: Increased rates of movement and the accumulation of insects establishing outside their native range is leading to the 'global homogenization' of agricultural and forestry pests. We use an invasive wasp, Leptocybe invasa (Hymenoptera: Eulophidae), as a case study to highlight the rapid and complex nature of these global invasions and how they can complicate management options. To trace the invasion history of L. invasa globally, we characterised the genetic diversity within and between populations from its origin and invaded regions using mitochondrial and nuclear markers. Three mitochondrial Haplogroups were identified, of which two are likely different species that appear to have been independently introduced into different parts of the world. One type (Mitochondrial Haplogroup 1) occurs globally, and is the exclusive type found in Europe, the Middle East, South America and most of Africa. The second type (Mitochondrial Haplogroup 2) co-occurs with the first-type in Laos, South Africa, Thailand and Vietnam, while a third type (Mitochondrial Haplogroup 3) occurs exclusively in Australia, its native range. The distinction of the two invasive Haplogroups was supported by analysis of newly developed simple sequence repeat (microsatellite) markers in populations from 13 countries. Further analyses using clustering methods and approximate Bayesian computation suggested the occurrence of hybridisation in the Laos population and revealed that an unsampled population was the origin of Mitochondrial Haplogroup 1. The analyses also showed little genetic differentiation within the invasive populations, suggesting a limited original introduction from a very small population followed by rapid, global range expansion in a stepwise fashion. Results of this study should provide some guidelines for characterizing invasion pathways of new invasive insect pests.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Michael J. Wingfield, Helen F. Nahrung, Brett P. Hurley

Research topic(s) for pests/diseases/weeds:
molecular biology - genes
population dynamics/ epidemiology

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Leptocybe invasa		Laos
	Leptocybe invasa		Thailand
	Leptocybe invasa		Vietnam
	Leptocybe invasa		South Africa