Recipient Organization
UTAH STATE UNIVERSITY
(N/A)
LOGAN,UT 84322
Performing Department
Biology
Non Technical Summary
Wild bees provide important services in every ecosystem, including those most influenced by human occupancy. These ecosystem services include providing a food base for wildlife, soil displacement during nest excavation, and pollination of most flowering plants, including our most important crops. However, bee diversity and abundance is declining rapidly due to changes in climate and habitat loss. Being able to predict how bees and the ecosystem services they provide will respond to changing environmental conditions requires understanding the physiological underpinnings of how bees interact with their environment. The primary aim of this proposed research is to understand how wild bees respond to environmental change. Specifically, I will investigate how investment in the most fundamental aspects of life - immunity, survival, and reproduction - is influenced by variable ecological and social conditions relevant to climate change.First, I will survey the metabolic costs and strength of immunity as a function of sociality acrossa variety of wild bee species. Second, I will investigate how immune response varies according to social and ecological context withinspecies. Finally, I will experimentally adjust social and ecological conditions and measure individual responses in terms of reproductive output, immunity, and energy reserves. Understanding how wild bees allocate investment in these life history traits will advance science and benefit the public by forming the foundation for maintaining pollinator populations in the face of a changing climate.
Animal Health Component
10%
Research Effort Categories
Basic
90%
Applied
10%
Developmental
(N/A)
Goals / Objectives
The goal of this project is to expand knowledge about how bees respond to environmental change.Objective 1. Survey life history trait investment across a broad range of beesObjective 2. Evaluate how social and ecological factors correspond to variation in life history traits within speciesObjective 3. Experimentally assess how bees adjust their investment in life history traits in response to changing environmental conditions
Project Methods
I will meet the objectives outlined above by studying a variety of bee species under natural and experimental conditions. Additional species will be added or substituted as methods are refined, and additional personnel join my lab.Objective 1. My students and I will compare metabolic investment in immunity as a function of social organization using a standardized laboratory assay within a phylogenetic framework. We will collect wild bees of various species that vary in social organization. We will measure immunity as the encapsulation response over a four hour period following insertion of a nylon filament. We will measure metabolic rate during this period as carbon dioxide production, following a one hour acclimation period. After identifying each bee to species, we will measure total energy reserves (sugars, glycogen, lipids) of each individual bee using established protocols. We will measure differences in encapsulation response among species as a function of body size, stored energy (lipids, sugar, glycogen), social organization, and time of year. We will use phylogenetic least squares regression models to account for the phylogenetic relationships among species. We will also use this method to examine the relationship between metabolic rate and immune (encapsulation) response as a function of social organization.Objective 2. My students and I will measure intraspecific variation in immune response as a function of social and ecological conditions. We will focus on two bee species with flexible social organization, such that some individuals live in social colonies for part or all of their life, while others are solitary for their entire lives (Megalopta genalis, Halictus rubicundus). The flexible social organization of these species allows my team and I to investigate how sociality and ecological variation influence immune response in a naturalistic experiment. We will measure innate immune activation among individuals from solitary and social nests. We will administer an immune challenge for each individual by inserting a nylon filament into the abdomen of each bee for four hours, as described for Objective 1. Within each species, we will test the role of reproductive activity and energy reserves as predictors of the immune response. We will use generalized linear models to model grey value as a function of reproductive activity and energetic resources, along with body size, and time of year.Objective 3. My students and I will experimentally alter three socio-ecological factors and observe the life history response in observation nests of Halictus rubicundus. We will manipulate (1) climate, (2) resource availability, and (3) social environment and measure the response in terms of (1) reproductive output, (2) innate immune response, and (3) energy reserves. Each experiment will be completed in artificial nests (30 x 30 x 0.5 cm) placed within large outdoor mesh enclosures (3 x 3 x 1.8 m). This set-up will allow us to track reproductive and social activity within the nest while controlling resource availability. We will use generalized linear models to evaluate how immune response, reproductive output, and energy reserves respond to changes in each of our experimental variables. We will include body size and time of year as predictor variables in each model, along with nest and cage id as random effects. We will also statistically evaluate how life history tradeoffs are altered by these environmental changes. Specifically, we will look for significant interactions between our experimental manipulations and reproductive output and energy reserves as they predict immune response.