Abstract/Summary

In recent years pollinator populations have been declining worldwide, while concurrently tropospheric ozone concentrations have been increasing. It has been shown that plant-pollinator communication is partially mediated by volatile organic compound (VOC) based communication and this communication method is susceptible to perturbation as a result of ozone exposure. However, to date, no single study has investigated the individual mechanisms that cause the perturbation of VOC based communication in isolation of each other. This thesis tested and or modelled the effect of several of these mechanisms on the antennal electrophysiological responsesof Apis melliferain isolation, namely:i)VOC blend ratio alteration, ii)VOC degradation product formation, and iii)Secondary organic aerosol (SOA) formation.Testing and/or modelling was conductedunder two landscape-scale scenarios, applyinga literature derived average foraging distance for A. melliferaof 400mwhen undertaking comparisons.Modellingdemonstrated that, under these modelling parameters,alterations inVOC blend ratioas a result of ozone pollution maycauselarge changesin electrophysiological response for some compounds with minor changes for others.Several VOC degradation products were identified and elicited statistically significant electrophysiological antennal responses. Whileit was demonstrated that each of the VOCs tested was capable of forming SOA as a result of their reaction with ozone,exposure of A. melliferaantennaeto SOAdid not cause a statistically significant change in antennal electrophysiological response to two stimuli during or after SOA exposure. It was also observed that any effects of these mechanisms were likely to be greater under an ozone excess landscape scenario which may be akin to a small group of flowers in an open landscape. This work has not only shown the potential of differing mechanisms to contribute to VOC communication perturbation, thus allowing for the synthesis of further work to characterise the most at-risk plant-pollinator interactions but has also highlighted the effect that landscape may have on these interactions.