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Effect of Sublethal Doses of Clothianidin and/or V. destructor on Honey Bee (Apis mellifera L.) Health, Behavior and Associated Gene Expression

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dc.contributor.advisor Guzman-Novoa, Ernesto
dc.contributor.author Morfin Ramirez, Nuria
dc.date.accessioned 2018-02-12T17:18:57Z
dc.date.available 2019-02-09T06:00:14Z
dc.date.copyright 2018-02
dc.date.created 2018-02-09
dc.date.issued 2018-02-12
dc.identifier.uri http://hdl.handle.net/10214/12547
dc.description.abstract Little is known about the effects of sublethal doses of neonicotinoids on honey bee (Apis mellifera L.) behaviors and mortality, and whether those effects are altered with parasitism by V. destructor. This study examined the effects of multiple exposures to field-realistic sublethal doses of clothianidin with and without V. destructor on adult bees and newly emerged bees treated as larvae. For adult exposure, memory retention decreased with each stressor alone, but weight and sugar consumption decreased only by the effect of V. destructor. For larval exposure, haemocyte counts increased with clothianidin but decreased with V. destructor, clothianidin reduced hygienic behavior and the number of foraging trips of the adults that emerged. Interactions between the stressors were observed as decreased weight of newly emerged bees with larval exposure, an increased mortality in adult bees, and a decreased intense grooming behavior with adult exposure. The relative expression of several immune and neural related honey bee genes showed an interaction between the stressors using two-way ANOVA in many cases. Also, the dose response of gene expression often revealed a non-linear pattern, implying hormesis, although hormesis was not detected for any of the biological measurements. For example, AmpUf68 expression in newly emerged bees showed an interaction between the stressors with a J-shaped dose response to clothianidin and no dose response to clothianidin plus V. destructor, while AmDef-2 expression in adults showed an interaction between stressors with an inverted U-shaped dose response to clothianidin and a sigmoidal dose response to clothianidin plus V. destructor. RNAseq analysis of bees with the highest sublethal doses of clothianidin with and without V. destructor showed no changes in the magnitude of expression but reduced numbers of differentially expressed genes with the combined stressors compared to each stressor alone. However, novel differentially expressed genes were also observed with the combined stressors. The combined stressors appeared to both change and inhibit the numbers of differentially expressed genes compared to each stressor alone. In general, clothianidin and V. destructor have different effects on bee health and behavior that was only rarely affected when combined, whereas gene expression mostly had reduced and unpredictable, rather than additive, effects with the combined stressors. en_US
dc.description.sponsorship Consejo Nacional de Ciencia y Tecnologia (CONACyT); Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA), Pinchin Family en_US
dc.language.iso en en_US
dc.rights Attribution-NonCommercial-NoDerivs 2.5 Canada *
dc.rights.uri http://creativecommons.org/licenses/by-nc-nd/2.5/ca/ *
dc.subject Apis mellifera en_US
dc.subject Honey bees en_US
dc.subject clothianidin en_US
dc.subject Varroa destructor en_US
dc.subject interaction en_US
dc.subject stressors en_US
dc.subject biotic stressor en_US
dc.subject abiotic stressor en_US
dc.subject gene expression en_US
dc.subject deformed wing virus en_US
dc.subject neonicotinoids en_US
dc.subject sublethal doses en_US
dc.title Effect of Sublethal Doses of Clothianidin and/or V. destructor on Honey Bee (Apis mellifera L.) Health, Behavior and Associated Gene Expression en_US
dc.type Thesis en_US
dc.degree.programme Environmental Sciences en_US
dc.degree.name Doctor of Philosophy en_US
dc.degree.department School of Environmental Sciences en_US
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Attribution-NonCommercial-NoDerivs 2.5 Canada Except where otherwise noted, this item's license is described as Attribution-NonCommercial-NoDerivs 2.5 Canada