Protecting a nation's primary production sector and natural estate is heavily dependent on the ability to determine the risk presented by incursions of exotic insect species. Identifying the geographic origin of such biosecurity breaches can be crucial in determining this risk and directing the appropriate operational responses and eradication campaigns, as well as ascertaining incursion pathways. Reading natural abundance biogeochemical markers using mass spectrometry is a powerful tool for tracing ecological pathways as well as provenance determination of commercial products and items of forensic interest. However, application of these methods to trace insects has been underutilised to date and our understanding in this field is still in a phase of basic development. In addition, biogeochemical markers have never been considered in the atypical situation of a biosecurity incursion, where sample sizes are often small, and of unknown geographic origin and plant host. These constraints effectively confound the interpretation of the one or two isotope geo-location markers systems that are currently used, which are therefore unlikely to achieve the level of provenance resolution required in biosecurity interceptions. Here, a novel approach is taken to evaluate the potential for provenance resolution of insect samples through multiple biogeochemical markers. The international pest, Helicoverpa armigera, has been used as a model species to assess the validity of using naturally occurring δ2H, 87Sr/86Sr, 207Pb/206Pb and 208Pb/206Pb isotope ratios and trace element concentration signatures from single moth specimens for regional assignment to natal origin. None of the biogeochemical markers selected were individually able to separate moths from the different experimental regions (150–3000 km apart). Conversely, using multivariate analysis, the region of origin was correctly identified for approximately 75% of individual H. armigera samples. The geographic resolution demonstrated with this approach has considerable potential for biosecurity as well as other disciplines including forensics, ecology and pest management.
Release rate and trapping experiments found new lure dispensers differed in release rate characteristics from existing dispensers under temperate and subtropical conditions, and indicated some potential for improvement in surveillance efficacy.
Emerging infectious diseases pose a considerable threat to wildlife globally. One such disease that has apparently emerged in recent years in New Zealand is avian malaria, with Plasmodium infections being detected in numerous species for the first time. Although the overall significance of this apparent emergence is not yet known, infection by Plasmodium has been diagnosed as a cause of mortality in several native species in captivity. Here we investigate the epidemiology of the most recently confirmed case, with our results having potentially important implications for native bird management. Avian malaria caused the death of five mohua or yellowheads (Mohoua ochrocephala) at Orana Wildlife Park in Canterbury during 2003-05, after their translocation from the Blue Mountains (Otago) in 2003. A lack of detectable Plasmodium infection in wild mohua in both the Blue Mountains and the nearby Catlins region, in contrast to an unusually high prevalence in wild bird populations at Orana Park at the time of the outbreak, indicates that infection was most likely acquired by the birds after translocation. This evidence, although not conclusive, strongly argues for assessment of the risk of greater (and potentially deleterious) exposure to malarial parasites to be undertaken prior to native bird translocation. A mosquito investigation carried out at Orana Wildlife Park identified the ubiquitous indigenous mosquito Culex pervigilans as the likely disease vector. Hence, management of this mosquito species (in addition to the exotic Cx. quinquefasciatus, a known vector of avian malaria in other countries) is a potentially useful preventative measure against disease outbreaks in native bird populations of conservation value in New Zealand.
Rationale Strontium isotopes are valuable markers of provenance in a range of disciplines. Limited amounts of Sr in low‐mass samples such as insects mean that conventional Sr isotope analysis precludes their use for geographic origins in many ecological studies or in applications such as biosecurity. Here we test the viability of using inductively coupled plasma tandem mass spectrometry (ICP‐MS/MS) with N2O as a reaction gas for accurately determining Sr isotopes in insects with Sr < 100 ng. Methods Strontium isotopes were determined in solution mode using ICP‐MS/MS with 0.14 L/min N2O as a reaction gas to convert Sr+ into SrO+ for in‐line separation of 87Sr from 87Rb. The Sr isotope reference standards NIST SRM 987, NIST SRM 1570a and NIST SRM 1547 were used to assess accuracy and reproducibility. Ten insect species collected from the wild as a proof‐of‐principle application were analysed for Sr concentration and Sr isotopes. Results Using ICP‐MS/MS we show for the first time that internal mass bias correction of 87Sr16O/86Sr16O based on 88Sr16O/86Sr16O works to give for NIST SRM 987 a 87Sr/86Sr ratio of 0.7101 ± 0.012 (RSD = 0.17%) and for NIST SRM 1570a a 87Sr/86Sr ratio of 0.7100 ± 0.009 (RSD = 0.12%), which are within error of the accepted values. The first 87Sr/86Sr ratio of NIST SRM 1547 is 0.7596 ± 0.0014. Strontium analyses were run on 0.8 mL of 0.25–0.5 ppb Sr, which equates to 2–4 ng of Sr. Strontium isotope analysis with a precision of >99.8% can be achieved with in‐line separation of 87Sr from 87Rb at least up to solutions with 25 ppb Rb. Conclusions A minimum of 5 mg of insect tissue is required for Sr isotope analysis. This new ICP‐MS/MS method enables Sr isotope analysis in single insects, allowing population‐scale studies to be feasible and making possible applications with time‐critical uses such as biosecurity.
Arhopalus ferus (Mulsant) (Coleoptera: Cerambycidae) is a forest pest that does not occur in Australia. In February 2010, the container ship Tatiana Schulte, en route from New Zealand, was refused permission to enter Australia following the discovery of numerous A. ferus aboard. The place where the infestation occurred was unknown, representing an uncontrolled biosecurity-risk pathway. Hydrogen isotope analysis of the beetles' wings showed that the infestation most likely originated from Auckland, New Zealand.
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