Development of the compound eyes of the water stick insect, Ranatra linearis
Résumé
Relationships between estimation of predator-prey distance prior to a capture attempt and some features of the compound eye are investigated at all stages of post-embryonic development. Interommatidial angles increase gradually from the anterior and the dorsal regions to the posterior and ventral regions. Facet diameters vary only slightly over the eye surface but increase with age. New ommatidia appear around the borders of eye after each moult. The older ommatidia are pushed away from the border. From one instar to another ommatidia change their direction of view from between 10d̀ to 30d̀ relative to the body axes. This change in direction far exceeds the calculated changes in direction that would be optimal if ommatidia were to continue viewing the same relative directions in space. This suggests a high degree of plasticity of the underlying neuronal networks.