A Sahel migrant: Oedaleus senegalensis
Locusts are grasshoppers that, in response to certain environmental cues including high population density, will shift from solitarious to gregarious phenotypes, which can subsequently lead to swarms. This phenomenon is termed locust phase polyphenism (78, 79) and is poorly understood in non-model locust species like Oedaleus senegalensis(80).
O. senegalensis is a grass-feeder and a major pest of millet and other cereal crops of subsistence agriculture in the Sahel zone of West Africa. Eggs start hatching with the first precipitation events of the rainy season (38), which historically occur from June through September.O. senegalensis typically produces three generations that all migrate following the Intertropical Convergence Zone (38). We conducted our experiments in August 2017 to coincide with the development of the first generation which is responsible for critical damages to seedling millet.