Journal of Pest Science
Population genetics of the Australian eucalypt pest Thaumastocoris
peregrinus: evidence for a recent invasion of Sydney
· Ashley Montagu
· Ann Noack
· Helen Nahrung
· Heng Wei
· Mark Eldridge
· Karen‑Ann Gray
Harley A. Rose
· Gerasimos Cassis
· Rebecca N. Johnson
· Simon Lawson
Received: 11 December 2017 / Revised: 21 May 2018 / Accepted: 25 May 2018
© Springer-Verlag GmbH Germany, part of Springer Nature 2018
Biological invasions represent a major threat to agriculture and forestry across the globe. Thaumastocoris peregrinus is a
small sap-sucking heteropteran bug that has recently invaded a number of eucalypt plantations worldwide from its native
range in Australia. To date, no studies have examined the range of this insect within Australia, and its population genetics
remain poorly understood. We sampled T. peregrinus from 16 populations from South East Queensland, across New South
Wales (NSW) and Victoria to south-eastern South Australia, and generated microsatellite and mtDNA data for ~ 200 indi-
viduals. Population genetic analyses consistently revealed moderate levels of genetic isolation by distance among populations
across the range. Nonetheless, T. peregrinus has undergone dispersal across large distances, as revealed by the presence of
identical mitochondrial haplotypes in both South East Queensland and South Australia. Two populations within the Sydney
area (NSW) were divergent from other populations based on STRU CTU RE and factorial correspondence analysis. They also
had relatively low allelic richness and haplotype diversity indices. These results suggest they are the result of a relatively
recent invasion event, consistent with their discovery in 2001. Pairwise genetic distance analyses suggest that the source
of the invasion may have been central NSW. Our study provides an important framework for understanding the biology of
this pest in its native environment, and may have implications for determining how it has invaded multiple areas worldwide.
Keywords Bronzing bug · Hemiptera · Invasive insect pest · Microsatellites · Mitochondrial COI · Plantation forestry
Thaumastocoris peregrinus is an emerging pest of euca-
lypt plantations worldwide; however, no studies have
examined the population genetics of this species in its
native range of Australia.
We sequenced both mitochondrial and microsatellite
DNA from 16 T. peregrinus populations in order to inves-
tigate the level of genetic structure of this species across
its native range, and test the hypothesis that individuals
in Sydney represent a recent invasion.
We provide evidence that the insect in Sydney is distinct
from other populations, and that it appears to be a recent
invasion, whose source may be central NSW.
Communicated by B. Hurley.
Nathan Lo and Ashley Montagu have contributed equally to this
Special Issue: “Invasive Pests of Forests and Urban Trees”.
Electronic supplementary material The online version of this
article (https ://doi.org/10.1007/s1034 0-018-0995-8) contains
supplementary material, which is available to authorized users.
* Nathan Lo
School of Life and Environmental Sciences, The University
of Sydney, Sydney, NSW 2006, Australia
Forest Industries Research Centre, University of the Sunshine
Coast, Sippy Downs, QLD 4556, Australia
Australian Museum Research Institute, Australian Museum,
1 William St, Sydney, NSW 2010, Australia
School of Biological, Earth, and Environmental Sciences,
The University of New South Wales, Sydney, NSW 2033,