Desert Locusts: Can Mathematical Models Help to Control Them?

Abstract

The ravages created by desert locusts (Schistocerca gregaria) on livelihoods and food security have been known and feared for thousands of years. Under the right conditions, the usually solitary insects suffer a radical transformation in terms of their body size, color, brain, and their behavior shifts to gregarious. In their gregarious form, locusts can eat about the equivalent of their body weight (2 g) per day. FAO calculates that a swarm of just 1 km² can consume as much food as would be eaten by 35,000 people in a single day. Their highly developed migratory capacity, with the ability to travel up to 150 km per day (they are carried by winds), allows them to easily go across borders and even continents.

Mathematical models have been developed to model different aspects of desert locust dynamics, from demographics to prediction of breeding grounds. Given the central importance of climatic conditions for desert locusts’ breeding and reproduction, temperature and humidity predictions are key variables. Likewise, given that locusts rely on wind for their transportation, wind velocity, direction, and temperature are also key variables in prediction models. The chapter describes the threats posed by locusts, the responses developed to contrast them, and the types and roles of mathematical models in these responses.