NSF Postdoctoral Fellowship in Biology FY 2021:Parasitism-induced changes in host behavior across scales: linking molecular basis to community impacts

Fitch, Gordon, Ann Arbor MI

Investigators

Abstract

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2021, Integrative Research Investigating the Rules of Life Governing Interactions Between Genomes, Environment and Phenotypes. The fellowship supports research and training of the fellow that will contribute to the area of Rules of Life in innovative ways. Diverse animal species respond to parasite infection with self-medication, seeking out resources that reduce the severity or duration of infection. Yet we know little about the molecular drivers of self-medicating behaviors, or about how self-medicating behavior scale up to affect populations of the ‘medicinal’ resource species. The fellow’s research will tackle these questions by studying the response of bumble bees to infection by a common and ecologically important gut parasite, Crithidia bombi. In doing so, the fellow will develop a framework for understanding how parasite infection operates across scales of organization from the biomolecule, to the individual, to the community, and will also contribute to understanding of the effects of Crithidia on bumble bee pollination. The project will first determine how Crithidia infection alters foraging-related gene expression in bumble bees, using comparative transcriptome analysis of brain and gut tissues from infected and uninfected bees allowed to choose between nectar solutions that differ in ‘medicinal’ secondary metabolite concentration. Then, laboratory choice experiments with captive bees will be used to determine the behavioral mechanism (i.e. preference vs. reduced discernment) underlying increased consumption of nectar high in ‘medicinal’ secondary metabolites by infected bees. Finally, tent experiments with infected and uninfected microcolonies, provisioned with a field-realistic floral community that includes thyme plants of distinct chemotypes, will test whether parasitism-induced changes to foraging have differential fitness consequences for two thyme (Thymus vulgaris) chemotypes (one with high nectar concentrations of ‘medicinal’ secondary metabolites, the other with low concentrations). Bee foraging behavior and thyme seed production will be compared across treatments in a factorial 2 x 2 infection status x plant chemotype design. Through this project, the fellow will develop critical skills in transcriptomics, chemical ecology, and behavioral ecology. The fellow will also develop and deliver related educational outreach activities to engage middle-school youth in science and conservation. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.