Duration of behaviour patterns during oviposition by the bruchid beetle, Callosobruchus maculatus

The behaviour of insects between making contact with a potential oviposition site and the act of oviposition itself determines the conditions in which their progeny begin development and, in many cases, whether a crop or commodity is damaged. In this paper the behaviour of female cowpea seed beetles, Callosobruchus maculatus (Fabricius) (Coleoptera: Bruchidae), during this period has been examined. The duration of discrete behaviour patterns within this period and the transitional frequencies between them have been used to compare the behaviour of beetles on two different hosts. In a 30-min period, beetles laid more eggs on mung than adzuki beans and rejected mung as an oviposition site much less frequently. A log-linear contingency table analysis of the transitional frequencies indicated a highly significant interaction between successive behaviours and between the second of the two behaviours and the host seed, indicating that the sequence of behaviours is partially determined by the host seed. Grooming, departure from the seed and loops in behavioural sequences occur more often on adzuki than mung and are indicative of a less acceptable host. Discriminant analysis showed that the total time spent exhibiting different behaviour patterns was significantly different on the two hosts. Mann–Whitney tests revealed small but significant differences in the mean durations of only three behaviour patterns on the two seed types. Measurement of the duration of each behavioural pattern confirms what can be deduced about host acceptability by observing the simple occurrence of different behavioural patterns and the determination of the frequency of transitions between them. Differences in acceptability were predominantly reflected in the frequency of certain behaviour patterns and of particular transitions from one pattern to another, not in the mean duration of each exhibition of a defined behaviour pattern. It is argued that the utility of measuring the duration of behavioural elements could only be demonstrated because behavioural patterns or categories were precisely defined.