Plasticity in Control Systems for Insect Feeding Behavior

Abstract

The insect nervous system has provided excellent material for cellular and biochemical studies of neural information processing and integration. In particular, the physiological study of chemoreception in insects is more advanced than in any other animal group, in no small measure due to the seminal stimulation provided by V.G. Dethier (1955, 1976). In addition, the comparative physiology of the neural control systems regulating feeding behavior also received great impetus from Dethier’s work, particularly the viewpoint that insect-vertebrate comparisons could usefully illuminate general issues pursued by both groups (Dethier 1982; Moss and Dethier 1983; Dethier and Bowdan 1984). A very natural question arises as to the reality and extent of learned adjustments to the feeding control systems of insects. The remarkable learning skills of the honeybee provide a dramatic example of the sophisticated computational ability of some insect nervous systems and encourage the view that learning questions posed in ethologically relevant terms might reveal learning of a high order in other insect species, including flies. During the last 20 years there has been a veritable explosion of work with mammals on food-assessment learning mechanisms, using behavioral paradigms that are readily adapted to insects. Thus the stage is set to assess the learning abilities of flies and a variety of other insect species in ways that both pose the learning question in terms natural to the animars Umwelt and facilitate comparisons with analogous results from the mammalian learning literature.