Flies That Fight

Summary by Deependra Chhabra



The average fly has always been a pest to society especially during the summer season. Flies are well known for the annoying "buzzing" sound they emit while they are swarming around, trying to find food. In fact, flies inhabit every corner of the globe. Some flies are mistaken as a specie related to the beetles because of their pronged antlers, untypical of a normal house fly. Evolution has certainly created new forms of flies across the world. Amazingly, stalk-eyed flies of the diopsid family see better by carrying their eyes at the tip of needle-thin stalks (or antennas). However, we rarely get a glimpse of these unique flies because they inhabit the tropical world.

The antlered flies and the stalk-eyed flies fight over breeding territories and release a special breeding scent from glands, visible on the fly as a lump on the underside of his abdomen. The ideal territories for flies to breed are on the trunks of particular rain forest trees. These rain forest trees provide wood to help nurture the diet of the larvae. Usually when two flies fight over a territory, they must first be the same size then combat follows, if not, the one with the longer antlers or eyestalks forces the other to back off. Always when there is a female fly present during battle, the winner will mate with her. After mating the male fly guards her, keeping other males away to ensure that her offspring will be his. At any point during the fertilization process, if another male mated with her then his genes would dominate. Moreover, in Queensland, Australia, the Phytalmia mouldsi males deters his contenders by straddling onto females. In conclusion, due to sexual selection certain fly species have developed longer antlers and eyestalks to meet their reproductive survival needs.


Moffett, W. M. (1997, November). Flies that fight. National Geographic, pp. 68-77.