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.
Calotropin
Monarch butterflies are one of many insects that feed on milkweed plants. These butterflies feed on the North American milkweed ("Asclepias)" plants. These milkweeds are related to the Indian and North African milkweeds ("Calotropis"), which are consumed by the North African grasshopper "Poekilocerus bufonis". These insects have adapted to the toxicity of the milkweed, are capable of safely sequestering cardenolides from the milkweed in glands or tissues during their early stages of development. The insects primarily retain calotropin and calactin (a configurational isomer), even though other cardenolides exist in the plant latex and leaves. These poisons, while not harmful to the insect, make it unpalatable to birds and mammals, and therefore serve as a defense mechanism. Monarch butterflies also store several volatile pyrazines, which give off an odor, which is a warning signal to predators to avoid the insect. "P. bufonis" is capable of utilizing calotropin in its defensive spray.