Desert invertebrates live in an environment where resources alternate unpredictably between brief periods of plenty and prolonged scarcity. This book describes the adaptive strategies of desert invertebrates in acquiring energy and sustaining life with such fluctuations. Some cooperate in foraging; others compete for resources. Some are nomadic and migrate to more favorable sites as conditions change. Others conserve energy by going into a deep dormancy until better conditions return. Still others store food during plentiful periods so as to retreat underground during less favorable times. The adaptive modes of economizing on scarce energy resources are diverse and lead to an appreciation of the intricate interactions of animals living close to their environmental limits.