Individual based modelling: a study of the correlation between Mopane caterpillar outbreaks and the movement of African elephants

Abstract

The research study aims to determine whether elephants move in relation to mopane caterpillar outbreaks. This will be done by means of mathematical modelling and an Individual-Based Model (IBM). The IBM will serve as a Decision Support Tool (DST) which will aid researchers at Save the Elephants-South Africa (STE-SA) in deciding whether an investment in this research field will render any meaningful returns. The study will focus on three species, namely the elephant, the mopane caterpillar and the mopane tree. Mopane is classified as a staple food item for elephants and can therefore have a significant impact on the foraging of elephants. The mopane caterpillar feeds on mopane leaves until pupation, and induces a change in the composition of the leaf chemistry. This change renders the leaf more palatable, as the amount of tannin in the leaf is reduced. Elephants, in turn, feed on the mopane. As a large quantity of an elephant's day is spent eating, it can be deduced that the distribution of mopane may have a large effect on the movement of elephants. Therefore, the possibility exist that defoliation by the mopane caterpillars can have an effect on the movement of elephants due to the decrease of tannin in the leaf once the tree flushes with new foliage after defoliation.