Stereotyped pattern of locomotion controlled by duration of previous tracking by a predatory insect.

Abstract

AMONG insects, an encounter with a particular stimulus1–4 or the performance of a particular activity5–7 may change the animal's later responsiveness to other stimuli or may prime the regular appearance of a stereotyped action pattern. Thus, various unrelated species display strictly predictable behavioural changes which depend not only on simultaneous events in the external environment as well as on general physiological variables, but also on well determined sensory or motor components of the subject's antecedent behaviour. The study of these changes may aid the understanding of the nature of specific internal mechanisms which are influenced by previous behavioural states and which act in turn on the animal's subsequent behaviour. This may be of special interest in the study of highly elaborate action patterns, such as the figure-of-eight dance of the honey bee. In this example, the return of the bee from a given food source to the hive is followed by a precisely defined pattern of locomotion, in which the timing and orientation of certain parameters depend on specific aspects of the insect's outgoing flight8. A series of experiments analysed the reactions of the aquatic dragonfly larva Aeschna cyanea M. after a brief presentation of an artificial prey stimulus. They revealed that the behaviour of the insect is influenced by the nature and former location of the stimulus, even after the latter has disappeared9. On the other hand, after a more extended presentation of a moving target—a stimulus which typically elicits prolonged tracking behaviour—the insect reliably carries out a strongly stereotyped pattern of locomotion, the form, control and function of which are described here.