Stalk-eyed fly

Long eye stalk = many girlfriends! Taken at night in Singapore forest.

Quote from en.wikipedia.org/wiki/Stalk-ey…

Stalk-eyed flies are insects of the fly family Diopsidae. The family is distinguished from most other flies by the possession of "eyestalks": projections from the sides of the head with the eyes at the end. Some fly species from other families such as Drosophilidae, Platystomatidae, and Tephritidae have similar heads but the unique character of Diopsidae is that the antennae are located on the stalk, rather than in the middle of the head as in all other flies.

The size of the stalk-eyed flies span up to a centimeter long, and they feed on both decaying plants and animals. Their unique morphology has inspired a great deal of research into how the attribute may have arisen through forces of sexual selection and natural selection. Studies of the behavior of the Diopsidae have yielded important insights into the development of sexual ornamentation, the genetic factors that maintain such a morphological feature, sexual selection, and the handicap principle.

There are more than one hundred species in the Diopsidae, with the greatest diversity found in the Old World tropics.[1] They are distributed throughout the region, with the best known species being from South-East Asia and Southern Africa. There are also two species in North America and a European species has recently been found in Hungary.[2]

Adult diopsids are typically found on low-lying vegetation in humid areas, often near streams and rivers, where they feed on fungi and bacteria that they scavenge from decaying vegetation. The larvae are saprophagic or phytophagous, eating decaying and fresh plant matter. Diopsis macrophthalma Dalman, 1817 is a pest of rice and sorghum in tropical Africa.

The peculiar morphology of stalk-eyed flies makes it easy to identify their fossils (e.g. in amber); one prehistoric genus that has been discovered in that form is Prosphyracephala.

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.[11][12] 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.