Does Experience Play a Role in the Development of Insect Neuronal Circuitry?

Abstract

Historically, the invertebrate nervous system has been thought of as a machine (Fabre, see Teale, 1949), a machine whose invariant design and function are determined by genetic factors alone and are therefore relatively inflexible. Modern-day invertebrate neurobiologists refer to this aspect of their specimens’ nervous systems as “hard-wired” or lacking in plasticity. A major thrust of invertebrate neurobiology has been the elucidation of the “wiring diagrams” of a wide range of nervous systems as a first step toward determining how nervous systems control behavior. As other chapters in this volume demonstrate, this approach to the invertebrate, particularly the arthropod, nervous system has led to insights into the organization of locomotory behaviors in all animals. In general, it has been assumed that the uncontrolled experience of an individual does not affect the wiring diagram of the nervous system in any significant way. This view, that the invertebrate nervous system is relatively inflexible, has received support from experiments which show that “experience” plays no role in the development of motor functioning. For example, rearing crickets in isolation does not affect the development of the songs they sing as adults (Bentley and Hoy, 1974). Similarly, rearing lobsters without swimmerets does not alter the motor program controlling swimmeret beating (Davis, 1973a).