Vision
Despite the unusual morphology of the eye, each compound eye sees a region of space extending over more than a hemisphere in all directions. Thus, there is extensive binocular overlap, with about 70% of the ommatidia of each eye having a binocular partner ommatidia in the opposite eye which views in the same direction. The binocular field is most extensive in the frontoventral quadrant, where it reaches over 135 °, and is smallest in the dorsal region. Researchers found that the behavior of stalk-eyed flies is very much determined by vision. During the day, temporary territories may be defended by threatening behavior. At dusk the animals gather in small groups on selected threadlike structures, returning to the same site each day. When males of about equal size encounter one another within such a group they may engage in ritualized fights (or occasionally contact fights). Competitors are driven away by the dominant male. Conspecifics are most likely to elicit a threat or flight reaction when they are at a distance of about 50 millimeters, and reactions to model flies and reflections in a mirror also occur at about this distance.
Read more about this topic: Stalk-eyed Fly, Behavior
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