{"id":{"repo_id":"sask","oai_identifier":"oai:harvest.usask.ca:10388/17910"},"canonical_url":"https://search.dev.ndltd.org/etd/sask/oai:harvest.usask.ca:10388/17910","repository":{"repo_id":"sask","name":"University of Saskatchewan","base_url":"https://harvest.usask.ca/server/oai/request"},"display":{"title":"THERE IS NO PLANET B(EE): AN INTEGRATED APPROACH TO UNDERSTANDING DRIVERS OF POTENTIAL DECLINES IN BUMBLEBEE COMMUNITIES","abstract":"Global climate change, anthropogenic activity, and pollution all threaten the core functions of Earth’s biotic systems. Of those core functions, pollinators, particularly insect pollinators, are key to the functioning of most terrestrial ecosystems. Bumblebees (Hymenoptera: Apidae: Bombus) represent important agricultural and urban pollinator species as they are tolerant of the high disturbance rates that characterize agricultural and urban systems. Over the past four decades, declines in the range, diversity, and biomass of bumblebees have been well documented. Most studies link climate change and anthropogenic activity to these declines, yet we lack understanding of the fundamental mechanisms that underlay these declines. This lack of understanding hinders attempts at conserving bumblebee communities as we lack information on the physiological and behavioral responses of bumblebee species to climate change and anthropogenic activity. To address this, I performed a series of behavioral and developmental assays with a model bumblebee species Bombus impatiens, alongside analysis of historical collections, to assess the viability of inferences drawn from B. impatiens to other bee species and in complex field environments. Using a series of two choice and no-choice assays, I assessed the effect of climate change associated plant stressors on B. impatiens foraging behavior and hive development in a laboratory setting. Using the mass flowering crop canola (Brassica napus), I found that climate change associated plant stress resulted in decreased hive populations and negative outcomes for key markers of forager efficiency. In behavioral assays, foragers demonstrated variable responses in their detection and avoidance of stressed plants, suggesting that impacts to forager efficiency may have long term effects on hive development and reproduction that relates to the specific plant stress encountered in the field. These results demonstrate the direct effects of climate change associated plant stress on B. impatiens and provide a measurable trait, size, and mechanism, forager efficiency, which can be assessed to identify if these trends carry across species and settings. To evaluate applicability of these inferences from B. impatiens broadly to Bombus spp., I used historical collection data to assess changes to forager size and bumblebee community composition in response to a climate associate plant stress, drought. Analysis of historical collections data suggests that plant stress, drought, effects forager size in non-model species, but the intensity of that effect is dependent on the species’ foraging range. Finaly, I used a variety behavioral assays and X-Ray Fluorescence Imaging (XFI) to assess changes to forager efficiency in B. impatiens and Bombus huntii from a common urban and industrial pollutant, chromium (Cr). Behavioral assays show similar negative effects to learning, memory, as a result of Cr exposure in both B. impatiens and B. huntii. Post exposure to Cr, B. huntii did not improve in learning or memory as compared to B. impatiens suggesting that there may be similarity in the negative effect of exposure across some species, but post exposure recovery may be species dependent. XFI imaging shows Cr accumulating in the mushroom bodies of the brain and may be impairing sensory information processing. Based on the above findings, it can be concluded that climate change and anthropogenic activity have consistent negative effects on forager efficiency, which may serve as the fundamental backbone that drives community composition for bumblebees. Behavioral responses and recoveries were variable and may not be conserved across bumblebee species. Understanding exactly how each species is affected may be necessary for the development of conservation goals. Physiological responses were more uniform and may serve as a valuable measure to assess the effectiveness of bumblebee conservation methods.","abstract_html":"Global climate change, anthropogenic activity, and pollution all threaten the core functions of Earth’s biotic systems. Of those core functions, pollinators, particularly insect pollinators, are key to the functioning of most terrestrial ecosystems. Bumblebees (Hymenoptera: Apidae: Bombus) represent important agricultural and urban pollinator species as they are tolerant of the high disturbance rates that characterize agricultural and urban systems. Over the past four decades, declines in the range, diversity, and biomass of bumblebees have been well documented. Most studies link climate change and anthropogenic activity to these declines, yet we lack understanding of the fundamental mechanisms that underlay these declines. This lack of understanding hinders attempts at conserving bumblebee communities as we lack information on the physiological and behavioral responses of bumblebee species to climate change and anthropogenic activity. To address this, I performed a series of behavioral and developmental assays with a model bumblebee species Bombus impatiens, alongside analysis of historical collections, to assess the viability of inferences drawn from B. impatiens to other bee species and in complex field environments. Using a series of two choice and no-choice assays, I assessed the effect of climate change associated plant stressors on B. impatiens foraging behavior and hive development in a laboratory setting. Using the mass flowering crop canola (Brassica napus), I found that climate change associated plant stress resulted in decreased hive populations and negative outcomes for key markers of forager efficiency. In behavioral assays, foragers demonstrated variable responses in their detection and avoidance of stressed plants, suggesting that impacts to forager efficiency may have long term effects on hive development and reproduction that relates to the specific plant stress encountered in the field. These results demonstrate the direct effects of climate change associated plant stress on B. impatiens and provide a measurable trait, size, and mechanism, forager efficiency, which can be assessed to identify if these trends carry across species and settings. To evaluate applicability of these inferences from B. impatiens broadly to Bombus spp., I used historical collection data to assess changes to forager size and bumblebee community composition in response to a climate associate plant stress, drought. Analysis of historical collections data suggests that plant stress, drought, effects forager size in non-model species, but the intensity of that effect is dependent on the species’ foraging range. Finaly, I used a variety behavioral assays and X-Ray Fluorescence Imaging (XFI) to assess changes to forager efficiency in B. impatiens and Bombus huntii from a common urban and industrial pollutant, chromium (Cr). Behavioral assays show similar negative effects to learning, memory, as a result of Cr exposure in both B. impatiens and B. huntii. Post exposure to Cr, B. huntii did not improve in learning or memory as compared to B. impatiens suggesting that there may be similarity in the negative effect of exposure across some species, but post exposure recovery may be species dependent. XFI imaging shows Cr accumulating in the mushroom bodies of the brain and may be impairing sensory information processing. Based on the above findings, it can be concluded that climate change and anthropogenic activity have consistent negative effects on forager efficiency, which may serve as the fundamental backbone that drives community composition for bumblebees. Behavioral responses and recoveries were variable and may not be conserved across bumblebee species. Understanding exactly how each species is affected may be necessary for the development of conservation goals. Physiological responses were more uniform and may serve as a valuable measure to assess the effectiveness of bumblebee conservation methods.","abstract_has_math":false,"creators":["Bryan, Caleb"],"institution":"University of Saskatchewan","degree_name":"Doctor of Philosophy (Ph.D.)","degree_level":"Doctoral","degree_discipline":"Plant Sciences","degree_department":null,"school":null,"contributors":[],"advisors":["Prager, Sean"],"committee_chairs":[],"committee_members":["Sharbel, Tim","Links, Matt","Wood, Sarah","Parkin, Isobel","Phillips, Ian","Willenborg, Chris","McFredrick, Quinn"],"year":2026,"date_issued":"2026-02-06","date_published":"2026-02-06","updated_at":"2026-07-24T04:27:01Z","subjects":["Bumblebees, climate change, plant stress"],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/10388/17910","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Prager, Sean"]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Sharbel, Tim","Links, Matt","Wood, Sarah","Parkin, Isobel","Phillips, Ian","Willenborg, Chris","McFredrick, Quinn"]},{"key":"dc:creator","label":"Author","values":["Bryan, Caleb"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2026-02-06T15:37:32Z"]},{"key":"dc:date.issued","label":"Date","values":["2026-02-06"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Plant Sciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy (Ph.D.)"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Saskatchewan"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Bumblebees, climate change, plant stress"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/10388/17910"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Global climate change, anthropogenic activity, and pollution all threaten the core functions of Earth’s biotic systems. Of those core functions, pollinators, particularly insect pollinators, are key to the functioning of most terrestrial ecosystems. Bumblebees (Hymenoptera: Apidae: Bombus) represent important agricultural and urban pollinator species as they are tolerant of the high disturbance rates that characterize agricultural and urban systems. Over the past four decades, declines in the range, diversity, and biomass of bumblebees have been well documented. Most studies link climate change and anthropogenic activity to these declines, yet we lack understanding of the fundamental mechanisms that underlay these declines. This lack of understanding hinders attempts at conserving bumblebee communities as we lack information on the physiological and behavioral responses of bumblebee species to climate change and anthropogenic activity. To address this, I performed a series of behavioral and developmental assays with a model bumblebee species Bombus impatiens, alongside analysis of historical collections, to assess the viability of inferences drawn from B. impatiens to other bee species and in complex field environments. Using a series of two choice and no-choice assays, I assessed the effect of climate change associated plant stressors on B. impatiens foraging behavior and hive development in a laboratory setting. Using the mass flowering crop canola (Brassica napus), I found that climate change associated plant stress resulted in decreased hive populations and negative outcomes for key markers of forager efficiency. In behavioral assays, foragers demonstrated variable responses in their detection and avoidance of stressed plants, suggesting that impacts to forager efficiency may have long term effects on hive development and reproduction that relates to the specific plant stress encountered in the field. These results demonstrate the direct effects of climate change associated plant stress on B. impatiens and provide a measurable trait, size, and mechanism, forager efficiency, which can be assessed to identify if these trends carry across species and settings. To evaluate applicability of these inferences from B. impatiens broadly to Bombus spp., I used historical collection data to assess changes to forager size and bumblebee community composition in response to a climate associate plant stress, drought. Analysis of historical collections data suggests that plant stress, drought, effects forager size in non-model species, but the intensity of that effect is dependent on the species’ foraging range. Finaly, I used a variety behavioral assays and X-Ray Fluorescence Imaging (XFI) to assess changes to forager efficiency in B. impatiens and Bombus huntii from a common urban and industrial pollutant, chromium (Cr). Behavioral assays show similar negative effects to learning, memory, as a result of Cr exposure in both B. impatiens and B. huntii. Post exposure to Cr, B. huntii did not improve in learning or memory as compared to B. impatiens suggesting that there may be similarity in the negative effect of exposure across some species, but post exposure recovery may be species dependent. XFI imaging shows Cr accumulating in the mushroom bodies of the brain and may be impairing sensory information processing. Based on the above findings, it can be concluded that climate change and anthropogenic activity have consistent negative effects on forager efficiency, which may serve as the fundamental backbone that drives community composition for bumblebees. Behavioral responses and recoveries were variable and may not be conserved across bumblebee species. Understanding exactly how each species is affected may be necessary for the development of conservation goals. Physiological responses were more uniform and may serve as a valuable measure to assess the effectiveness of bumblebee conservation methods."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["THERE IS NO PLANET B(EE): AN INTEGRATED APPROACH TO UNDERSTANDING DRIVERS OF POTENTIAL DECLINES IN BUMBLEBEE COMMUNITIES"]}]}],"canonical_facts":{"dc:contributor.advisor":["Prager, Sean"],"dc:contributor.committeemember":["Sharbel, Tim","Links, Matt","Wood, Sarah","Parkin, Isobel","Phillips, Ian","Willenborg, Chris","McFredrick, Quinn"],"dc:creator":["Bryan, Caleb"],"dc:date.accessioned":["2026-02-06T15:37:32Z"],"dc:date.issued":["2026-02-06"],"dc:description.abstract":["Global climate change, anthropogenic activity, and pollution all threaten the core functions of Earth’s biotic systems. Of those core functions, pollinators, particularly insect pollinators, are key to the functioning of most terrestrial ecosystems. Bumblebees (Hymenoptera: Apidae: Bombus) represent important agricultural and urban pollinator species as they are tolerant of the high disturbance rates that characterize agricultural and urban systems. Over the past four decades, declines in the range, diversity, and biomass of bumblebees have been well documented. Most studies link climate change and anthropogenic activity to these declines, yet we lack understanding of the fundamental mechanisms that underlay these declines. This lack of understanding hinders attempts at conserving bumblebee communities as we lack information on the physiological and behavioral responses of bumblebee species to climate change and anthropogenic activity. To address this, I performed a series of behavioral and developmental assays with a model bumblebee species Bombus impatiens, alongside analysis of historical collections, to assess the viability of inferences drawn from B. impatiens to other bee species and in complex field environments. Using a series of two choice and no-choice assays, I assessed the effect of climate change associated plant stressors on B. impatiens foraging behavior and hive development in a laboratory setting. Using the mass flowering crop canola (Brassica napus), I found that climate change associated plant stress resulted in decreased hive populations and negative outcomes for key markers of forager efficiency. In behavioral assays, foragers demonstrated variable responses in their detection and avoidance of stressed plants, suggesting that impacts to forager efficiency may have long term effects on hive development and reproduction that relates to the specific plant stress encountered in the field. These results demonstrate the direct effects of climate change associated plant stress on B. impatiens and provide a measurable trait, size, and mechanism, forager efficiency, which can be assessed to identify if these trends carry across species and settings. To evaluate applicability of these inferences from B. impatiens broadly to Bombus spp., I used historical collection data to assess changes to forager size and bumblebee community composition in response to a climate associate plant stress, drought. Analysis of historical collections data suggests that plant stress, drought, effects forager size in non-model species, but the intensity of that effect is dependent on the species’ foraging range. Finaly, I used a variety behavioral assays and X-Ray Fluorescence Imaging (XFI) to assess changes to forager efficiency in B. impatiens and Bombus huntii from a common urban and industrial pollutant, chromium (Cr). Behavioral assays show similar negative effects to learning, memory, as a result of Cr exposure in both B. impatiens and B. huntii. Post exposure to Cr, B. huntii did not improve in learning or memory as compared to B. impatiens suggesting that there may be similarity in the negative effect of exposure across some species, but post exposure recovery may be species dependent. XFI imaging shows Cr accumulating in the mushroom bodies of the brain and may be impairing sensory information processing. Based on the above findings, it can be concluded that climate change and anthropogenic activity have consistent negative effects on forager efficiency, which may serve as the fundamental backbone that drives community composition for bumblebees. Behavioral responses and recoveries were variable and may not be conserved across bumblebee species. Understanding exactly how each species is affected may be necessary for the development of conservation goals. Physiological responses were more uniform and may serve as a valuable measure to assess the effectiveness of bumblebee conservation methods."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["https://hdl.handle.net/10388/17910"],"dc:language.iso":["en"],"dc:subject":["Bumblebees, climate change, plant stress"],"dc:title":["THERE IS NO PLANET B(EE): AN INTEGRATED APPROACH TO UNDERSTANDING DRIVERS OF POTENTIAL DECLINES IN BUMBLEBEE COMMUNITIES"],"dc:type":["Thesis"],"thesis:degree_discipline":["Plant Sciences"],"thesis:degree_level":["Doctoral"],"thesis:degree_name":["Doctor of Philosophy (Ph.D.)"],"thesis:institution_name":["University of Saskatchewan"]},"updated_at":"2026-07-24T04:27:01Z"}