Natal origin of the invasive biosecurity pest, brown marmorated stink bug (Halyomorpha halys: Penatomidae), determined by dual‐element stable isotope‐ratio mass spectrometry

Abstract

BACKGROUND Post‐border detection of a single brown marmorated stink bug (BMSB) in New Zealand warranted a biosecurity response, the nature of which would be influenced by its status as part of an established population or as a new arrival. Stable isotope analysis has the potential to determine natal origins, but is difficult to achieve for samples as small as a single insect. Here an analytical modification to measure small samples was successfully trialled as a means to supply evidence as to the local or exotic natal origin of the intercepted BMSB specimen. RESULTS Sufficient analytical sensitivity was achieved using a modified isotope ratio mass spectrometry method, involving thermolysis and carbon monoxide cryofocusing, to enable the simultaneous analysis of δ2H and δ18O from wings of the post‐border BMSB sample. The values were much lower than those of the New Zealand green vegetable bug, used as a local reference. However, they fell within the range of those for BMSB of Northern Hemisphere origin intercepted at the New Zealand border over the same time period, specifically overlapping with the USA and Italy, but not China. CONCLUSION The isotope signature of the post‐border detected BMSB suggested a significantly cooler climate than the North Island of New Zealand, indicating that it was a new arrival and did not represent an established population. © 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

A bioavailable strontium (87Sr/86Sr) isoscape for Aotearoa New Zealand: Implications for food forensics and biosecurity

“…One of the highest risk pests for Aotearoa is the exotic brown marmorated stink bug ( Halymorpha halys ) because it feeds on over 300 species of plants and infestation can ruin entire crops [ 7 ]. Recent attempts to define the origins of this invasive stink bug used δ 2 H and δ 18 O isotopes from their wings to determine whether a bug detected post-border represented a recently introduced foreign bug or an established population [ 2 ]. Holder et al [ 2 ] concluded that the distinct δ 2 H and δ 18 O isotope signature of their wings suggested a cooler climate origin, supporting evidence that the specimen was not from a locally breeding, southern hemisphere summer population.…”

“…Recent attempts to define the origins of this invasive stink bug used δ 2 H and δ 18 O isotopes from their wings to determine whether a bug detected post-border represented a recently introduced foreign bug or an established population [ 2 ]. Holder et al [ 2 ] concluded that the distinct δ 2 H and δ 18 O isotope signature of their wings suggested a cooler climate origin, supporting evidence that the specimen was not from a locally breeding, southern hemisphere summer population. Currently, there are no rapid response tools to assess the provenance of these pests when they are introduced which limits the ability to develop effective measures to prevent their arrival in Aotearoa.…”

“…This new analytical method enables this technology to be used within the limits for biosecurity, commanding very short time frames and availability of very little biological material. Now, coupled with this 87 Sr/ 86 Sr isoscape, well supported decisions based on probabilities can be made as to the likely Aotearoa or offshore origin of foreign pests, which is key to determine the most efficient response to prevent their establishment [ 2 ]. Prior to this point this had not been possible, anywhere.…”

“…Provenancing biological products and organisms in Aotearoa using biogeochemical analyses has been investigated for both food forensics and biosecurity. To date it has been restricted to use of the isotopes of light elements (typically δ 2 H, δ 18 O, δ 15 N, δ 13 C, and some others) and trace element concentrations, including for the verification of products such as milk powders [ 10 , 11 ], wine [ 12 ], fetal bovine serum [ 13 ], or for insect pest biosecurity breaches [ 2 ]. Currently in Aotearoa, private company Oritain offers origin verification for food and related products [ 14 ].…”

“…Importantly, δ 2 H and δ 18 O variations on the landscape vary continuously and at low spatial resolution, as well as seasonally, making the values redundant regionally [ 33 – 35 ]. Although, in rare situations, the spatial and seasonal distributions of δ 2 H and δ 18 O can be useful to differentiate between materials originating from the northern and southern hemispheres [ 2 ]. Generally, however, all else being equal it can be challenging to isotopically distinguish between ecosystems that are geologically and climatically similar using only δ 2 H and δ 18 O [ 34 , 36 ] because the variation and patterning of atmospheric isotopes may not be distinct enough.…”