BEHAVIORAL CIRCADIAN-RHYTHMS MEASURED IN REAL-TIME BY AUTOMATIC IMAGE-ANALYSIS - APPLICATIONS IN PARASITOID INSECTS

A video analysis system was developed to study behavioural circadian r hythms in insects. Technical innovations were performed in image analy sis and in the use of robotics. In image analysis, both the automatic detection of the insect and the calculation of several variables (line ar and angular speed, locomotor activity, etc.) are carried out in rea l-time, which saves time and allows long-term studies without any inte rvention of the operator. The displacement of the camera by robotics a llows the simultaneous study of many individuals (i.e. sixty individua ls for the study of locomotor activity of adult insects, more than 400 individuals for the study of the emergence of adult parasitoids from their host). Four applications of this new device are presented. They deal with circadian rhythms in parasitoid insects: locomotor activity and time variation in locomotory parameters, daily distribution of the emergence and onset of the locomotor activity in adults. The adaptabi lity of the system to several experimental materials and situations is discussed and the interest of the study of behavioural rhythms in the approach of host-parasitoid associations is emphasized.