The dynamics of spatially structured populations (metapopulations) have been widely studied over the last few decades. For the sake of simplicity, most of these studies assume that all the constituent local populations (subpopulations) experience similar rates of migration (immigration and emigration). Although it is intuitively obvious that nothing in nature constrains the migration rates to be symmetric, i.e. same over all subpopulations, this problem seems to have eluded the attention of theoretical and empirical ecologists. After some preliminary simulation studies, it is found that compared to the symmetric case, asymmetric migration is likely to lead to very different metapopulation dynamics in terms of stability and synchrony. More importantly, the effects of asymmetric migration might interact with the intrinsic growth rates of the subpopulations concerned.
The present project aims to investigate this interaction using a combination of theoretical tools based on analytical/computational non-linear dynamics, and experiments on laboratory metapopulations of the fruitfly, Drosophila melanogaster.
This is a joint project with IISER Pune. The experimental work is being carried out by Dr. Sutirth Dey, IISER Pune. On the theoretical side of this work which is carried out by Dr. Nithin Nagaraj at Amrita, tools from symbolic dynamics and information theory is employed to investigate the properties of coupled map lattices.
While both these approaches have been used extensively in physics and engineering, they have not been applied in the context of biological systems like populations. Specifically, the project proposes to investigate the Mutual Information and Shannon’s Entropy of the subpopulations undergoing symmetric/asymmetric migration to get insights into the “information flow” between these subpopulations.