Desert locusts, which are usually solitary and inoffensive, can fastly become gregarious and form gigantic swarms that devastate vegetation
What are the mechanisms behind this and what factors trigger it? Along with the FAO Commission for Controlling the Desert Locust in the Western Region and several other organizations in North and West Africa, we have undertaken research to pinpoint the environmental conditions and insect densities that lead Desert locusts to become gregarious. The aim is to anticipate and manage attacks by this pest more efficiently.
What are the mechanisms behind Desert locust gregarization and what factors trigger it?
A study by CIRAD and partners has shown that the state of the vegetation (dry or green) influences the gregarization of adult individuals.
The Desert locust is an invasive pest that is both well known and feared because of the large-scale agricultural damage it can cause
It is particularly closely monitored, to prevent the risks of outbreaks and invasions. Climate change could modify its distribution area, meaning a new threat to agriculture, according to a study published in the journal Global Change Biology by researchers from CIRAD and INRA.
They were thought to be sedentary during their solitary phase, whereas they can travel several kilometres
Populations were considered fragile, whereas they are actually perfectly suited to their environment and much larger than previously thought. Desert locusts had us all fooled. We recently demonstrated this through a wide-ranging genetic study in collaboration with numerous African partners.
Preventive management of locust plagues works in some cases but still fails frequently
We have designed a multi-agent system to represent the events of a locust plague development and a management system with three levels: a funding institution, a national control unit and field teams. With this model, we aim at identifying the limits and potential improvements of the management system.
High resolution soil moisture is critically needed for the improvement of forecasts and early warning of a variety of plagues
Specifically, this project addresses the use of soil moisture to preventive management of the Desert locust, Schistocerca gregaria (Forskål, 1775), whose plagues have threatened agricultural production in Africa, the Middle East and Asia for centuries and regularly affect up to one-tenth of the world’s human population. Preventive management aims to prevent or to limit crop damage by controlling populations before they can reach high densities and form mass migrating swarms.
Domestication impacts on plant-insect-bacteria interactions
Domestication modified growth rate and nutrient contents of crop plants to fit human needs. It has also eventually reduced defence against herbivores and inadvertently impacted leaf microbial communities, which could interfere with plant-insect interactions. Examining whether and how selection of specific plant attributes can alter herbivores behaviour and life history through phylosphere modifications is crucial in the agroecological context. We explore these potential cross-effects with a wheat-locust-bacteria system.