SURVIVING IN A VARIABLE ENVIRONMENT: NUTRITIONAL ECOLOGY, BEHAVIORAL ECOLOGY, AND ECOLOGICAL IMMUNITY IN HONEY BEES
Abstract: All living organisms need nutrients to grow, survive, and reproduce. Acquiring nutrients in a variable environment, however, is not simple. Foragers partake in a complex balancing act of obtaining nutrients while maximizing the rate of energy gain, which is made difficult by biotic and abiotic factors. Furthermore, nutrients in the environment vary spatially and temporally, both within a... read morend between food items. In this dissertation, I used behavioral ecology to better understand how honey bees obtain the right nutrients, and stay healthy, under various environmental stressors. To investigate how bees cope with changes in distribution and abundance in floral, and thus nutritional, resources, I ran both manipulative and observational field studies throughout the year. Regarding micronutrients, bees likely forage in compound-rich water for minerals their floral diet lacks. Micronutrient requirements shifted with environmental and physiological factors, likely in preparation for winter. Regarding macronutrients, when restricted to a diet lacking amino acids, bees brought more pollen, the main source of protein, back to the hive. There was no change, however, in the diversity of floral sources brought back to the hive. When lacking amino acids, honey bees likely partake in compensatory foraging but may not search for specific floral resources. I used thermal imaging to understand how adult bees inside the hive work together to protect the colony from heat stress and disease. When the hive is subjected to heat stress, bees absorb heat and radially dissipate it away from the vulnerable brood. When infected with a heat-sensitive pathogen, bees work together to generate a colony-level fever and again, protect the brood. This colony-level fever, however, is not successful in smaller colonies. Lastly, I helped to implement an updated method to measure physiological immune response, with pathogen biology in mind. This method can be applied to learn more about ecological immunity in honey bees and the specificity of physiological immunity in insects. Studying honey bee nutritional ecology and ecological immunity has implications in broadening the field of nutritional ecology and implementing insect pollinator conservation.
Thesis (Ph.D.)--Tufts University, 2018.
Submitted to the Dept. of Biology.
Advisor: Philip Starks.
Committee: Sara Lewis, Harry Bernheim, Benjamin Wolfe, and Heather Mattila.
Keyword: Ecology.read less