The behavioural responses of isopods have been studied since the turn of the century. The experimental conditions need to be held constant strictly enough to merit comparison in spite of the differences in technique. The procedure involved in my own studies consisted principally of two criteria (Warburg 1964), firstly, the behaviour of an individual and secondly, the behaviour of a small group of animals (up to 10). With the first criterion I used two procedures: measurement of the actual time spent in one place (condition) and counting the number of times (n) the animal shifted from one alternative to the other. Thus, I could calculate the percentage of time spent at each ‘place’ (or ‘residence time’), as well as the speed at which an animal travelled from one place to another. These analytical indices could be used whether one used a choice-chamber apparatus (Fig. 9.1) or a temperature gradient apparatus (Fig. 9.2). In addition, it was possible to calculate the intensity of response (I); for details of these procedures, see Warburg 1964; Warburg and Berkovitz 1978a, b). With the experiments on groups of animals, another criterion was used of counting once every minute the positions held by each member of the group, without taking actual time measurements of their whereabouts.
KeywordsRhythmic Activity Terminal Segment Specific Odour Isopod Species Contact Chemoreceptor
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