The Flesh Fly: Sarcophaga crassipalpis



            Sarcophaga crassipalpis has a wide range of uses in the scientific world. Most notably, S. crassipalpis is one of the most common flesh flies in laboratory experiments, contributing information not only about its own genus and species, but about the entire Insecta class. S. crassipalpis is studied especially for its well-adapted responses to external stimuli, such as changes in climate and temperature, light patterns, and availability and exposure to mates (Nishida 1984). This includes the diapause process, which takes place during the pupal phase (see Form and Function).

            S. crassipalpis is also used in forensic entomology to estimate the time of death of potential homicide victims. Studying the internal physiology of the fly allows forensic entomologists to determine an approximate time of death, which can help to identify both the victim and the murderer (Kgware et al.). Unfortunately, flesh flies are relatively rare colonizers of human remains, but they most often appear early in the decomposition process (Nishida 1984; Diaz & Kaufman 2011). This makes them a vital contributor to information when present.


Sex Differences in Behavior

            Male flesh flies are much more territorial than female flesh flies. In the wild, male S. crassipalpis has been known to create lookout points from which he can pay careful attention to his surroundings; when other insects invade, he attacks. When a female enters his territory, he can capture her as a potential mate. Studies have provided evidence that male territoriality is not related to defending resources but to establishing dominance and increasing one’s chances of finding a mate. S. crassipalpis females, on the other hand, are much more likely to exhibit tolerance toward other individuals (Paquette et al. 2008). For more on how behavioral differences in the sexes affect mating, visit our Reproduction page.


Danger            S. crassipalpis is relatively benign to humans, although they can be vectors for leprosy-causing bacteria. Furthermore, S. crassipalpis has been known to causes myiasis in animals, mostly sheep, but human cases have been reported (Kgware et al.). Cases of dermal, wound, or ophthalmomyiasis have been seen in humans when fly larvae are deposited under the skin, in open wounds, or in or near the eyes, respectively (Uni et al. 1999). These infections cause itchy sores and pus-filled lesions (Kgware et al.). Ophthalmomyiasis can also cause swelling of the eyelids, optical discharge, and conjunctivitis (Uni et al. 1999). Still, it is important to keep in mind that such cases are rare and that treatment is readily available in the United States.


Pest Management

            Flesh flies rarely inhabit houses or restaurants, preferring instead the resources offered by the outdoors, including manure and decay (Kgware et al.). In rare cases where S. crassipalpis has become a problem, the elimination of food sources for larvae (most often animal carcasses) and for adults (vegetable matter, especially decayed) has been sufficient to remove the infestation (Diaz & Kaufman 2011). For more information on the management of flesh flies and other vermin, see the University of Florida Guide to Household Pests.


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