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    Investigation, design and fabrication of miniaturized CMOS novel active RFID tags : Doctor of Philosophy in Engineering-Electronics, Information and Communication Systems at Massey University, Albany campus
    (Massey University, 2021) Kumari, Meera
    The drastic decline in the bee population in the past few years is alarming given the quantity and quality of global food reliance on these insect pollinators. To ensure sustainable crop production and maintain biodiversity, it has become an important area of research for entomologists to study the factors involved in the dramatic population decline of these tiny insects. Understanding the insect’s biology and their foraging behavior tracking in the agricultural landscape is crucial. However, due to the large size of the available PCB-based tracking tags knowing their true behaviours in the presence of various chemical fertilizers and pesticides is still a challenge. In this research, a very new VHF radio telemeter architecture has been developed which could facilitate tracking of a large number of small insects and bees wirelessly in real-time at a distance of around 1km. The architecture is based on a novel circuit topology to generate an extremely low duty cycle signal digitally which for the first time does not require any passive elements. This digital generation technique of the low duty cycle has made it possible to realize the complete telemeter design on 1mmX 1mm ASIC chip, except for the antenna and the battery, and eliminated the need for discreet components which are mounted on PCB. Due to inconsistent fabrication facilities, the telemeter circuit parts were implemented in CMOS8RF-130nm and 8HPP-28nm, but the final ASIC telemeter prototype is realized in TSMC 65nm process technology and the fabricated chip is experimentally tested in the lab to verify its performance in the manufacturing environment. The design consists of a digital core circuit to generate 8-bit binary-coded 0.0078 duty-cycled burst mode signaling and a full on-chip analog power management circuit to locally generate the required voltage supplies with predefined dependence on temperature for the digital circuitry with the compensation for the temperature variation on the telemeter performance. A white paper calculation has been presented to package the insect telemeter ASIC, along with 10cm antenna directly over 80mg, 5mmX5mmX1mm silver oxide battery to yield a 95mg complete telemeter package, making it to be the world’s smallest and the lightest VHF radio telemeter.
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    Temperature- and host-dependent transcriptional responses in the entomopathogenic bacterium, Yersinia entomophaga MH96 : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Genetics at Massey University, Albany Campus, New Zealand
    (Massey University, 2020) Paulson, Amber Rose
    Yersinia entomophaga MH96 is a virulent pathogenic bacterium that is infective towards a broad range of insects and is under development as a biopesticide. MH96 produces insecticidal toxin complex called Yen-TC that is secreted at temperatures of 25 °C and below and has been shown to be the primary virulence factor (VF) during per os challenge against the New Zealand grass grub, Costelytra giveni and other agricultural pests (Hurst et al., 2011a, 2019). New insights into the pathobiology of MH96 during insect infection were gained from the in vivo transcriptome, including identification of a core secreted weaponry of co-expressed/co-secreted VFs, including Yen-TC and other exoenzymes; however, many other diverse types of VFs, including toxins, effectors, fimbriae, secretion systems, efflux pumps, iron acquisition, stress response and metabolic adaptation were also identified as highly expressed under in vivo conditions. A small DNA-binding protein, Yen6, was shown to be under thermoregulation at the transcriptional level and host-dependent-regulation at the post-transcriptional level and contributed to virulence during intrahemocoelic infection of Galleria mellonella at 37 °C. The in vivo transcriptome of Δyen6 and in vitro DNA-binding specificity analysis provided evidence that Yen6 is a novel LytTR-containing regulator that activates a ribose uptake/metabolism gene cluster, rbsD-xylG-rbsC-xylF-rbsK-ccpA, and represses a fructose uptake/metabolism gene cluster, IIA-fruK-IIB and a gene for RNA-binding protein yhbY during infection at 37 °C. Another small DNA-binding protein, Yen7, was also implicated as a potential temperature-dependent activator of Yen-TC component genes and over-expression of yen7 resulted in restored secretion by MH96 at 37 °C; however, deletion of yen7 did not abrogate Yen-TC production. Experimental investigations into potential regulatory linkages between Yen6 and yen7 were undertaken, and evidence to date does not support Yen6 as transcriptional repressor of yen7. A 17.5 Kb unstable element within the genome of MH96 with linkages to Yen-TC and toxin secretion, motility and cell shape was identified. Overall the findings presented in this thesis represent the most detailed investigation of MH96 pathogenesis to date, reinforcing MH96 as one of the most highly entomopathogenic bacteria known to humankind; yet suggesting MH96 has possibly maintained at least one core thermoregulatory mechanism more typical of an opportunistic pathogen.
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    The non-target effects of the introduced parasitoid Trigonospila brevifacies (Hardy) (Diptera: Tachninidae) on the native fauna of New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Ecology at Massey University, Palmerston North, New Zealand
    (Massey University, 1999) Munro, Vanessa M W
    The Australian tachinid parasitoid Trigonospila brevifacies (Hardy) (Diptera: Tachinidae) was introduced to New Zealand 30 years ago as a biological control for the exotic orchard pest Epiphyas postvittana Walker (Lepidoptera: Tortricidae). Trigonospila brevifacies, an endoparasitoid of late-instar lepidopteran larvae, was introduced concurrently with Xanthopimpla rhopaloceros Krieger (Hymenoptera: Ichneumonidae), a parasitoid of lepidopteran pupae. Trigonospila brevifacies is now known to attack several non-target pest and non-pest lepidopteran species. The impact of T brevifacies on non-target fauna was investigated. Life history data (i.e., longevity, fecundity, productivity and sex ratio) for T. brevifacies were quantified in the laboratory. These data and field data were used to investigate whether superparasitism is an adaptive reproductive strategy for this species by comparing the return in adult progeny per egg for single and multiple egg clutches. Superparasitism may be advantageous for the survival of rare non-target hosts. Data from a two-year, six-site survey of native forests determined that T. brevifacies attacked eight non-target Lepidoptera. The characteristic common to the phylogenetically diverse host group was that all are concealed feeders. Laboratory testing showed that pre-imaginal conditioning of parasitoid larvae did not confer adults with a preference for the host species in which they were reared. Quantitative food web data from a two-year field survey showed that T. brevifacies was the numerically dominant parasitoid of the species attacking native Tortricidae at sub-canopy levels and that it competed for hosts with 12 native and one other introduced species of parasitoid. The abundance of larval hosts and T brevifacies was compared between the edges and centres of forest patches. Host density was determined by quadrat counts and parasitoid abundance by sticky traps. Both larval hosts and the parasitoid were more abundant at the forest edge. Trap hosts were also used to quantify parasitism levels along edge to forest-centre tansects. Parasitism by T. brevifacies was highest at forest edges declining to almost zero at 30m into a forest, indicating that forest centres with continuous canopy should offer hosts' refuge from T. brevifacies parasitism. Archival and field data were used to determine the present geographical ranges of T. brevifacies and X. rhopaloceros and climatic data were used to predict where else in New Zealand these two parasitoids are likely to colonise in the future.
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    Contributions to our knowledge of the Hemipterous genera Dieuches Dohrn (Lygaeidae : Rhyparochrominae), Rhypodes Stål (Lygaeidae : Orsillinae) and Chinamiris Woodward (Miridae : Mirinae) with supporting papers on other Rhyarochrominae, Orsillinae and Miridae, other Hemiptera, and insects in other orders : application for the degree of Doctor of Science from Massey University, Palmerston North, New Zealand
    (Massey University, 1992) Eyles, Alan Charles
    When the applicant was awarded a Sir Walter Mulholland fellowship in 1966, the opportunity arose for a post-doctoral fellowship at the University of British Columbia, Vancouver, Canada, where Professor G. G. E. Scudder was , and still is, working on the lygaeid subfamily Rhyrparochrominae of the World. Here was the chance to work on a large, difficult genus containing species from many different parts of the world, and thus make a major contribution in this area. The choice was between Dieuches Dohrn and Pachybrachius Hahr. because no other genus in the Rhyparochrominae contains anything like the number of species contained by thesetwo genera. The complex genus Dieuches was selected. On account of his teaching and other duties, Professor Scudder's available time for research was not unlimited, and as he put it, it would be a great help to him to have that genus thoroughly revised. My training has been on Hemiptera, family Lygaeidae,with an M.Agr.Sc. thesis (Massey 1958) on Nysiushuttoni (White) - subfamily Orsillinae, and a Ph.D.thesis (University of London, 1962) on some Rhyparochrominae with special reference to their feeding habits.