The prey recognition algorithm and gross morphology of the praying mantis, Euchomenella macrops

We have discovered that a number of praying mantis species assess up to ten visual stimulus parameters to determine an object’s location in space and its suitability as prey; the parameters include size, geometry, contrast, movement pattern, and speed, among others. However, an unusual species, Eucomenella macrops, differs from other species in that it responds appetitively to visual stimuli that are both smaller and slower than do other species. This preference for smaller, slower prey may be related to the mantis’ relatively small, foreleg tibia. Further, an object need not be moving at the time that E. macrops strikes. The latter suggests that this mantis’ visual system retains information (i.e., has a memory of) object movement. These behavioral differences may be attributable to the unique eye morphology of E. macrops and to what Hebb termed “reverberating” circuits within the mantis’ visual system. In this case, movement sensitive, feature-detector visual interneurons may continue to discharge briefly after object movement has ceased and, thereby, trigger the strike after the cessation of stimulus movement.