Grasshopper
Grasshoppers eat large quantities of foliage both as adults and during their development, and can be serious pests of arid land and prairies. Pasture, grain, forage, vegetable and other crops can be affected. Grasshoppers often bask in the sun, and thrive in warm sunny conditions, so drought stimulates an increase in grasshopper populations. A single season of drought is not normally sufficient to stimulate a major population increase, but several successive dry seasons can do so, especially if the intervening winters are mild so that large numbers of nymphs survive. Although sunny weather stimulates growth, there needs to be an adequate food supply for the increasing grasshopper population. This means that although precipitation is needed to stimulate plant growth, prolonged periods of cloudy weather will slow nymphal development.
African migratory locust
The African migratory locust primarily feeds on grasses, including economically important crops, such as maize, millet, sorghum and wheat.
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. The band moves as a cohesive unit, pausing as the hoppers feed and bask in the sun, and merges with other bands. Bands have been known to travel for before they fledge into adults. The mutual attraction between the individual hoppers continues into adulthood and the insects continue to act as a cohesive group, a swarm.