A Multifunctional Role for Octopamine in Locust Flight

A complex cascade of neuronal, hormonal, muscular, and metabolic events leads to the initiation and maintenance of a behavioral act. Hormones are released to mobilize metabolic energy; muscle properties are altered to ensure the generation of the necessary force; neuronal circuits are activated to generate a specific locomotor pattern; and the neuronal circuit underlying respiration may also be altered to adapt the animal to increased oxygen consumption. All these events are part of a complex transition of the animal into a new behavioral state. A critical aspect of this transition is the need to alter these events at the appropriate time. This coordinating function may not only depend on neuronal interaction but may also be attributed to chemical substances that bias, at many levels, neuronal, hormonal, and muscular events towards the new functional state of the animal. For example, egg-laying by Aplysia spp. requires several peptides (38, 76) to elicit a complex of behaviors, including the cessation of locomotion, increase in heart and respiratory rate, egg laying, head waving, and mucous ecretion. Similarly, serotonin controls