Adipokinetic hormone functions that are not associated with insect flight

This review deals with some lesser known functions of adipokinetic hormones (AKHs), specifically those that are not associated directly with flight activity. The data summarized and discussed relate to AKHs in insects that have lost the ability to fly and use exclusively and/or mostly walking for their locomotion; and to activation of pathways that do not lead directly to production and subsequent rapid consumption of energy, but help the insect to combat stress Situations. Emphasis is placed on AKH-stimulated walking activities in Pyrrhocoris apterus, Gryllus bimaculatus, Periplaneta americana and Drosophila mellanogaster; diel fluctuations in AKH activities; the actions of AKH in alternative stress situations in which infection, toxins and other kinds of stressors interact; and the role of AKHs in anabolic processes and egg production. Possible mechanisms of action are proposed when justified by available knowledge.