Infected Ant Colonies Behavior Follows SIR Model to Reduce Epidemic Fatalities
https://www.sciencedaily.com/releases/2018/11/181123135020.htm
As discussed in class, the SIR epidemic model is one representation of tracking the transmissions of diseases by segmenting the population into three states of life: Susceptible, when an individual is at risk of contracting the disease, Infectious, when the individual carries the disease and is capable of passing the disease to other susceptible individuals, and Removed, when the individual can no longer effect others typically due to fatality from the disease. As a result, this model tracks the transmission probability upon contact and the number of contacts between infectious and susceptible individuals.
According to a collaborative study between IST Austria and University of Lausanne, researchers conducted various experiments indicating that upon entry of a pathogen into the colony, garden ants will alter their internal behavioral interactions to limit the potential damage. First, the researchers utilized a “barcode” system that captured the movements and interactions of marked ants. Then, researchers exposed fungal spores to the forager ants which amount to about 10% of all worker ants in the colony. The examined interactions indicated that upon entry of the fungal spores to worker ants, interactions between ants of different groups decreased sharply. In essence, groups with infected members were quarantined within their groups to decrease the potential contact between groups. A researcher rationalized that “In a colony, not all animals have to be protected, but the most valuable individuals should survive.” As a result, some groups such as queens, nurses, and young worker ants were able to limit infections within the group.
The ants’ behavior follows our SIR epidemic model as by dividing different groups, the amount of contacts between infected ants and susceptible sharply declined, consequently reducing the fatality of the epidemic within the colony.