Location

University of Richmond

Event Website

http://as.richmond.edu/programs/hhmi/science-symposium.html

Start Date

9-25-2015

End Date

9-25-2015

Document Type

Restricted Event: Campus only access

Description

The foraging behavior of bacterial-feeding nematodes was investigated using agent-based and differential equations-based modeling. Our goal was to simulate a nematode-bacteria predator-prey system as it would appear in a cubic foot of soil. We focused on two main search strategies: chemotaxis, where the searcher moves upward along a chemical concentration gradient, and infotaxis, where the searcher moves in the direction that allows it to maximize the amount of information it gathers about the location of the food source. In order not to violate the competitive exclusion principle, which states that two species that compete for the exact same resources cannot stably coexist, we proposed a predator-prey model that consists of two different species of bacterial-feeding nematodes, one with a specialist diet and one with a generalist diet, and two different species of bacteria, one that is preferred and one that is acceptable to the generalist diet. Parameters we incorporated into our model include moving speed, soil moisture, nematode sensitivity to bacterial chemical concentration gradients, and energy level changes due to movement and reproduction. We used video imaging software to track nematode movement in order to find the average nematode moving speed and to observe the different search strategies of nematodes under a microscope. Similar to other models on population dynamics, we found that, under certain dietary conditions, the populations of all four species oscillate stochastically about a stable limit cycle trajectory in phase space.

Comments

Department: Mathematics and Biology

Faculty Mentors: Dr. Michael Kerckhove, Dr. Amy Treonis

Share

COinS
 
Sep 25th, 12:00 AM Sep 25th, 12:00 AM

Poster Presentation: Mathematical Modeling of 4-by-4 Nematode-Bacteria Predator-Prey System

University of Richmond

The foraging behavior of bacterial-feeding nematodes was investigated using agent-based and differential equations-based modeling. Our goal was to simulate a nematode-bacteria predator-prey system as it would appear in a cubic foot of soil. We focused on two main search strategies: chemotaxis, where the searcher moves upward along a chemical concentration gradient, and infotaxis, where the searcher moves in the direction that allows it to maximize the amount of information it gathers about the location of the food source. In order not to violate the competitive exclusion principle, which states that two species that compete for the exact same resources cannot stably coexist, we proposed a predator-prey model that consists of two different species of bacterial-feeding nematodes, one with a specialist diet and one with a generalist diet, and two different species of bacteria, one that is preferred and one that is acceptable to the generalist diet. Parameters we incorporated into our model include moving speed, soil moisture, nematode sensitivity to bacterial chemical concentration gradients, and energy level changes due to movement and reproduction. We used video imaging software to track nematode movement in order to find the average nematode moving speed and to observe the different search strategies of nematodes under a microscope. Similar to other models on population dynamics, we found that, under certain dietary conditions, the populations of all four species oscillate stochastically about a stable limit cycle trajectory in phase space.

http://scholarship.richmond.edu/hhmi/2015/program/3