A Century of Invasion: How Biosecurity Influenced Populations of Sirex noctilio and Its Fungal Symbiont in Australasia

Firehiwot B. Eshetu; Irene Barnes; Helen F. Nahrung; Katrin N. E. Fitza; Bernard Slippers

doi:10.1111/mec.70311

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A Century of Invasion: How Biosecurity Influenced Populations of Sirex noctilio and Its Fungal Symbiont in Australasia

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A Century of Invasion: How Biosecurity Influenced Populations of Sirex noctilio and Its Fungal Symbiont in Australasia

Firehiwot B. Eshetu, Irene Barnes, Helen F. Nahrung, Katrin N. E. Fitza and Bernard Slippers

Molecular Ecology, Vol.35(6), pp.1-23

2026

DOI: https://doi.org/10.1111/mec.70311

PMID: 41876966

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Abstract

forest health

insect-fungus co-invasion

invasive insect pest

symbiosis

The woodwasp, Sirex noctilio, and its mutualistic fungal symbiont, Amylostereum areolatum, are native to Eurasia and northern Africa. Sirex noctilio was first reported outside its native range in New Zealand in 1900, Tasmania in 1952 and mainland Australia in 1961. In this study, we consider the invasion history of these organisms across Australasia through population genetic analysis using mitochondrial sequence data and microsatellite markers and compared them with a previously published dataset from global collections. The study included contemporary (n = 461) and historical (n = 41) samples of S. noctilio dating back to 1952 and fungal (n = 176) samples from across the range. No population structure was found in Australian and New Zealand populations of S. noctilio or the fungal symbiont A. areolatum, reflecting both the natural (within the countries) and human‐assisted (between the countries) spread of these symbionts. The S. noctilio populations in these countries had lower genetic diversity than other populations sampled globally. Amylostereum areolatum populations from Australia and New Zealand clustered separately from all other countries and were highly clonal. While the results suggested multiple early introductions in these two countries, it also reflected an efficient recent quarantine system that isolated these populations and reduced their complexity compared to other parts of the world. The findings also have relevance to the application of biological control for the pest complex.

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Title: A Century of Invasion: How Biosecurity Influenced Populations of Sirex noctilio and Its Fungal Symbiont in Australasia
Authors: Firehiwot B. Eshetu - University of Pretoria
Irene Barnes - University of Pretoria
Helen F. Nahrung - University of the Sunshine Coast
Katrin N. E. Fitza - University of Pretoria
Bernard Slippers (Corresponding Author) - University of Pretoria
Publication details: Molecular Ecology, Vol.35(6), pp.1-23
Publisher: Wiley-Blackwell Publishing Ltd.
Date published: 2026
DOI: 10.1111/mec.70311
ISSN: 1365-294X
PMID: 41876966
Copyright note: © 2026 The Author(s). Molecular Ecology published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Data Availability: A representative mitochondrial haplotype of the mtCOI sequence of S. noctilio and the mtSSU ribosomal RNA gene sequence of A. areolatum are available in NCBI. All the SSR data have been made available as Supporting Information data.
Grant note: This work was supported by the Australian National Sirex Co-ordinate Committee and the Tree Protection Co-operative Programme.
Organisation Unit: Forest Industries Research Centre
Language: English
Record Identifier: 991222601502621
Output Type: Journal article

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