Hi, I’m Tom Saunders.
PhD | Integrating chemical ecology with behavioural tests to improve risk assessment of biocontrol agents: Proactive biocontrol of BSMB in New Zealand with Trissolcus japonicus
My research applies chemical ecology techniques to biocontrol programmes in novel ways during the pre-release risk assessment phase, in order to get a better understanding of a classical biocontrol agents’ potential non-target effects before it is released. I’m using the host-specificity of Trissolcus japonicus against non-target NZ pentatomids as a case study, to determine how a variety of chemical ecology and traditional methods can be integrated to provide more certainty to regulators tasked with approving or declining applications to release new organisms. I’ll achieve this by (1) evaluating the host acceptance behaviour exhibited by T. japonicus in relation to an as yet untested non-target New Zealand pentatomid, (2) recording electrophysiological responses to non-target host odours across T. japonicus antennae using GC-EAD, (3) conducting arrestment experiments where retention time of the parasitoid is recorded when exposed to arenas contaminated with stink bug volatiles. This testing regime will provide valuable information relating to potential non-target risks posed by T. japonicus to non-target NZ species. But more importantly, it will allow us to: (1) assess the feasibility of these techniques when applied in a novel way to biocontrol programmes, (2) establish which of these methods may produce conflicting results, or results which are in broad agreement, and (3) assess the quality of results in light of their intended use to aid regulators with decisions to release new organisms. Ultimately, better methods for assessing risk means safer and more effective biocontrol programmes.
MSc | Optimising Capture Methods for the Evaluation of Parasitoid Wasp Diversity
Thesis publicly available at ResearchSpace.
My masters research focused on improving the ways that parasitoid wasps are caught, in order to help researchers studying their ecology or diversity. Parasitoid wasps are mega-diverse, ecologically dominant, but poorly studied components of global biodiversity. Despite their intensive application within pest management as biocontrol agents, little is known about native species. To understand their basic biology they must be collected in sampling programs. However, invertebrate surveys are increasingly subject to funding and time constraints that often preclude complete faunal inventories. In order to maximise the efficiency and reduce the cost of their collection, I proposed the application of optimal sampling techniques within a Rapid Biodiversity Assessment framework. Two sites in the Waitakere Ranges were sampled three times over the summer to determine the relationship between sampling effort and observed species richness. Statistical techniques such as rarefaction and non-parametric estimators were used to predict true species richness and to evaluate the completeness of sampling. Results showed that an intensive Malaise-trapping regime over the summer could capture two-thirds of parasitoid wasp species present. I provided sampling recommendations to guide optimal usage of Malaise traps for both ecological studies and faunal inventories. I also described a new species of native parasitoid wasp, representing the first New Zealand species from the genus Lusius (Ichneumonidae: Ichneumoninae). Morphological measurements confirm the new species represents a significant range expansion for the genus.
My masters was the first attempt to quantify sampling effort in relation to parasitoid wasp diversity in New Zealand. It showed that very high sampling effort failed to catch all species present. Parasitoid wasps are known to be keystone species that show promise as indicators of environmental quality and as surrogates for the diversity of other taxa. The development of optimal sampling strategies will therefore provide an important foundation for their future study. Another important theme emerging from my work was the importance of collaboration between ecologists and taxonomists. Projects planned with input from each of these disciplines would make better use of limited sampling resources, and provide more information on the biology of the captured taxa.