Gregarious insects have a flatter prothorax and are a pale tan or a greyish colour with dark markings.

[1] Some chemical factor in the foam produced by gregarious females encourages aggregation of the hoppers; if eggs are removed from the pod and reared separately, they develop into solitary individuals.

The duration of each instar depends on environmental factors and is shortest in hot, humid regions and longest under cooler, dry conditions.

[1] The African migratory locust primarily feeds on grasses, including economically important crops, such as maize, millet, sorghum, and wheat.

[3] The African migratory locust exists in its solitary form in many parts of Africa and its development is then similar to that of other grasshopper species.

When the eggs hatch in extremely close proximity to each other, the first-instar hoppers become attracted to each other and begin to form bands that move in synchrony.

[1] Swarms of the African migratory locusts fly by day and settle on the ground at night, where they rest and feed on vegetation.

"[4] This control was effective, and increasing dryland farming and better monitoring in Mali changed the character of the outbreak area such that by the 1980s, the insect's behaviour was thought to be more like that of a solitary grasshopper than a gregarious locust.

For many years after that, the African migratory locust was in recession, which perhaps lulled the authorities into a false sense of security.

The rains and more normal weather returned in 1984, providing ideal conditions for the locusts to breed abundantly.

The Desert Locust Control Organisation of East Africa remained an effective body, but elsewhere little monitoring was done, with civil wars in Chad and the Central African Republic hindering the detection of outbreaks.