Bioecology of North African Orthoptera

Organizer: Lahsen El Ghadraoui

The Orthoptera fauna of North Africa has been studied since 1943 by Chopard. Although ancient, this study remains a valuable reference for the identification of grasshoppers. However, the classification of Orthoptera has since undergone several reworkings and many new taxa have been identified. These insects constitute a particularly important group among phytophagous pests. Their role as primary consumers of plants sometimes makes them very harmful to agriculture. They cause enormous losses in agricultural and pastoral production, in a chronic or episodic way, especially during locust invasions. Because of the importance of their damage, the Orthoptera fauna requires a lot of work, both on the taxonomy and bio-ecology.

Under certain ecological conditions, some species – the locusts – proliferate dramatically and change for a gregarious phase. They gather in huge migratory swarms which move over great distances, falling on fields and making impressive damage in a short time. This is the case, for example, of Schistocerca gregaria, Locusta migratoria and Dociostaurus maroccanus. Their extraordinary voracity, vast polyphagia, astonishing fertility and great capacity to move in groups – swarms and hopper bands – make these locusts most important pests.

North Africa home a large number of devastating species of locusts and grasshoppers. About twenty species are considered as major pests to agriculture. And many of the hundred Orthoptera species of Morocco, Algeria and Tunisia are limited to restricted geographic areas and remain far from being satisfactorily known.

Monitoring and control of the locust pests require a thorough knowledge of the bioecology and population dynamics, in order to determine the most vulnerable stage of these insects to undertake a more effective and more environmentally friendly preventive control.