Visually Guided Search Behavior during Walking in Insects with Different Habitat Utilization Strategies

This review examines visually guided search behavior during walking in different species and developmental stages of insects having contrasting habitat utilization strategies. The discussion focuses on mantises, short-horned grasshoppers and crickets. Although generally short-horned grasshoppers are travelers, whereas mantises are ambush predators, all of these insects exhibit visually guided behavior during walking in the search for food sites and shelter. In crickets, which are central place foragers, visually guided behavior during walking is also important for nest site homing. Despite differences in habitat utilization, these three insect groups all use searches incorporating intermittent locomotion, where the distances traveled and duration of pauses have a distinct functional significance. However, there are also locomotion pattern variations, such as loops, zigzags, spiral patterns and straight lines. Search strategies during walking include searches with and without visual landmarks. The detection and recognition of stationary visual landmarks is based on self-induced retinal image displacement, with differing underlying neuronal mechanisms in the three insect groups. If a visual landmark is identified as a suitable target, a direct approach is elicited under either open- or closed-loop conditions, depending on the situation. In the presence of more than one suitable target object, the behavioral response can be temporarily restricted to stimuli associated with a particular area of the visual field, while information from other areas of the visual field is suppressed. The review concludes that there are gaps in knowledge concerning the various questions and thus further research is needed.