In the field, grasshopper nymphs may disperse from ‘spatially hostile’ homogeneous environments to heterogeneous habitats (longer grass) where there is adequate cover from predation or inclement weather. However, it is difficult to assess the velocity of walking and jumping movements of nymphs in the field, as accurate assessment of the distance moved and the dependence of behavior on the prevailing meteorological conditions are significant problems technically. A camera system monitored with EthoVision was used in controlled laboratory conditions to determine the movement velocity of nymphs of the grasshopper, Chorthippus parallelus, throughout their development in homogeneous and heterogeneous environments.
Movements of nymphs in the homogeneous environment generally seemed to be random for all instars, with a high occurrence of jumping. However, in the heterogeneous environment, jumping was less frequent and consequently movement velocities, particularly of late instars (3-4), were significantly lower than in the homogeneous environment. Although tracking of grasshoppers is challenging with regard to the natural characteristics of these insects, EthoVision is a useful tool for accurately determining movement velocity in grasshoppers.