Submission Type
Poster
Abstract
Optimal Foraging Theory has been widely used to study animal foraging behaviors, but has seldom been applied to symbiotic microbes like arbuscular mycorrhizal (AM) fungi. To date we know little about how AM fungi make decisions to forage in different nutrient patches. To help address this gap we here apply Optimal Foraging Theory to understand how AM fungi forage for nitrogen. We focus on nitrogen because AM fungi need more nitrogen than their plant hosts and soil nitrogen availability can shift the relationship between AM fungi and their hosts from mutualism to parasitism. We present a stochastic dynamic programming model to predict the optimal patch choice of AM fungi and changes in fungal fitness (measured in nitrogen and carbon content) in each time step in nitrogen foraging, based on a series of assumptions about AM fungal physiological traits. Our central hypothesis is that AM fungi forage independently from their plant hosts and make their own decisions about when and where to forage for nitrogen. Specifically, we focus on whether (1) AM fungi ignore, occupy or handle an encountered nitrogen patch and (2) previously encountered patches affect the choice made in the next encountered patch. The application of Optimal Foraging Theory in this system is novel, and by defining AM fungal nitrogen foraging behaviors, we will be able to significantly expand our understanding of AM fungal foraging and activity in soil.
Included in
Behavior and Ethology Commons, Environmental Microbiology and Microbial Ecology Commons, Other Ecology and Evolutionary Biology Commons
An optimal patch use model for nitrogen foraging in arbuscular mycorrhizal fungi
Optimal Foraging Theory has been widely used to study animal foraging behaviors, but has seldom been applied to symbiotic microbes like arbuscular mycorrhizal (AM) fungi. To date we know little about how AM fungi make decisions to forage in different nutrient patches. To help address this gap we here apply Optimal Foraging Theory to understand how AM fungi forage for nitrogen. We focus on nitrogen because AM fungi need more nitrogen than their plant hosts and soil nitrogen availability can shift the relationship between AM fungi and their hosts from mutualism to parasitism. We present a stochastic dynamic programming model to predict the optimal patch choice of AM fungi and changes in fungal fitness (measured in nitrogen and carbon content) in each time step in nitrogen foraging, based on a series of assumptions about AM fungal physiological traits. Our central hypothesis is that AM fungi forage independently from their plant hosts and make their own decisions about when and where to forage for nitrogen. Specifically, we focus on whether (1) AM fungi ignore, occupy or handle an encountered nitrogen patch and (2) previously encountered patches affect the choice made in the next encountered patch. The application of Optimal Foraging Theory in this system is novel, and by defining AM fungal nitrogen foraging behaviors, we will be able to significantly expand our understanding of AM fungal foraging and activity in soil.
