Neural circuit mechanisms of adaptation or sensitisation to neonicotinoid insecticides

Lead Research Organisation: University of Sheffield
Department Name: Biomedical Science

Abstract

"What doesn't kill you makes you stronger" - or does stress make you weaker? This PhD project addresses this question in the context of neuronal synaptic plasticity and insecticides. Many insecticides affect the nervous system and cause insects to behave strangely even at low doses, which is a major problem for honeybees and other insect pollinators harmed by agricultural pesticides.
Yet the nervous system is remarkably plastic and resilient to changes in activity levels. We recently identified an olfactory circuit in the fruit fly Drosophila that compensates for imbalances in excitatory and inhibitory input, a process known as homeostatic plasticity. This project will take advantage of the powerful genetic toolkit of Drosophila to study whether insect nervous systems can compensate for insecticides that increase synaptic excitation (i.e., "adaptation"). Compensation isn't always helpful though; recent hypotheses about episodic or developmental disorders like epilepsy and autism posit that compensation for one problem may render the nervous system more fragile for other stressors. Therefore, this project also asks whether compensating for sublethal doses of insecticide makes insects unhealthy in other ways ("sensitisation").
In this project, the student will use a range of cutting-edge techniques, including multiphoton imaging, electrophysiology, computational modelling, and behavioural assays.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
BB/M011151/1 30/09/2015 29/09/2023
1945515 Studentship BB/M011151/1 01/10/2017 30/09/2021 Daniel Green
 
Description The original aim of this project was to investigate potential negative effects pesticides that act to disturb brain function on none target species. In particular we were interested in testing how resilient the fruit fly olfactory associative learning system (a well defined system vital for locating food/ sexual partners ) and potentially validating the fruit fly olfactory learning system as a model for off target effects for pesticides which would allow us to study potential ways of preventing off target effects more easily. Unfortunately, when developing our learning assay we found it impossible to find a dose we could feed the flies at which they survived, showed defects in learning but no defects in movement. We found that the defects in movement were producing a selection effect in that we only got data from flies which moved the most and in all likelihood either received a lower dose of pesticide or were more resistant. In either case we concluded that fruit fly olfactory learning did not prove to be viable model of off target pesticide effects.
Exploitation Route This finding is important as it highlights some of the difficulties involved in developing models for the off target effects of neonicotinoid pesticide providing insight in to what others trying to do say should look out for as potential confounding effects. Furthermore, it will prevent others proceeding down the route we did unnecessarily saving other researchers time and effort.
Sectors Agriculture, Food and Drink,Chemicals,Government, Democracy and Justice,Other