A Photographic Method for the Study of Insect Migration

THE study of the migration of swarms of the desert locust (Schistocerca gregaria Forsk.) has involved the detailed analysis of the flight behaviour of the individual locusts constituting a swarm. Following Gunn et al.1, it has been shown that by placing a camera on the ground with the lens pointing upwards, it is possible to obtain photographs of locusts flying in a swarm which are ‘readable’ up to the limits set by the lens, the shutter-speed in relation to the ground-speed of the locust, and the emulsion used. These photographs have been useful for determining the orientation of individuals and also, from the size of the images and of a sample of the locusts under observation, the area-density and volume-density of the flying locusts in the layer of the swarm resolvable by the camera.