A pollination network of Cornus florida

Abstract

A POLLINATION NETWORK OF CORNUS FLORIDA By James H. Lee, Master of Science. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at Virginia Commonwealth University. Virginia Commonwealth University, 2014. Director: David Chan, Associate Professor, Dept. of Mathematics and Applied Mathematics. From the agent-based, correlated random walk model presented, we observe the effects of varying the parameter values of maximum insect turning area, δmax, density of trees, ω , maximum pollen carryover, κmax, and probability of fertilization, Pκ , on the distribution of pollen within a population of Cornus florida (flowering dogwood). We see that varying δmax and κmax changes the dispersal distance of pollen, which greatly affects many measures of connectivity. The clustering coefficient of fathers is maximized when δmax is between 60◦ and 90◦. Varying ω does not have a major effect on the clustering coefficient of fathers, but it does have a greater effect on other measures of genetic diversity. Lastly, we compare our simulations with randomly-placed trees with that of actual tree placement of C. florida at the VCU Rice Center, concluding that in order to truly understand how pollen is distributed within a specific ecosystem, specificity in describing tree locations is necessary.