Genetic tools for insect control

Darrington, Michael (2019) Genetic tools for insect control. Doctoral thesis, University of East Anglia.

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Pest insects can impose strains on public health and food security and these are predicted to intensify as a consequence of population growth and climate change. In the 20th century, organosynthetic insecticides were considered the panacea for insect control. However, insecticides have become less effective, as pest species have evolved mechanisms of behavioural and genetic resistahce. It imperative therefore, that novel modes of control are developed to eradicate or suppress wild, pest insect populations. In this thesis I tested various novel genetic tools and approaches for control of the Mediterranean Fruit Fly (Ceratitis capitata; medfly) and evaluated the Fall Armyworm (Spodoptera frugiperda; FAW} as a candidate species for Oxitec1s established "self-limiting11 control. I investigated environmental RNA interference (eRNAi) as a mode of control for the medfly and showed that neither medfly adults or eggs can easily be induced to become eRNAi competent via feeding or by exposure to electric current, respectively. I then sequenced and analysed the genome of a bacterium, aiming to modify it, for control of the medfly through paratransgenesis. The Klebsiel/a oxytoca bacterium identified did not exhibit obvious signatures of transition to an obligate relationship with its medfly host. However, it was capable of degrading pectate and may provide essential nutrients to medfly larvae, which consume a large amount of fruit. Next, I manipulated medfly eggs to test whether vertical transmission of K. oxytoca could occur by maternal 'egg smearing1 There was no clear evidence for this, though K. oxytoca holds some potential for control of the medfly through paratransgenesis. Finally, I studied the mating and sperm precedence behaviours of the FAW and showed that this species has potential utility as an agent of self-limiting control. Overall, the thesis research gives novel insights in the context of genetic insect control and tactical suggestions for future investigations.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Chris White
Date Deposited: 08 Apr 2021 09:47
Last Modified: 30 Nov 2022 01:38

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