**Flesh Flies** (family Sarcophagidae) are medium-sized flies commonly found worldwide. They are distinct from House Flies in several ways, most notably their gray, checkered abdomen and the fact that most species are **larviparous** (they deposit living larvae instead of eggs). While many species are harmless scavengers feeding on decaying organic matter, others are forensically important as indicators of time since death, and a few can cause **myiasis** (infestation of a living host) in animals and humans.
Taxonomy and Classification
Flesh Flies belong to the order Diptera (true flies). They undergo complete metamorphosis. The genus *Sarcophaga* is the largest, containing many common species. They are often confused with blow flies (Calliphoridae), but Flesh Flies lack the metallic coloration and have three distinct dark longitudinal stripes on the thorax (mid-body) and a distinct gray and black checkered pattern on the abdomen.
Physical Description
Adult Flesh Flies are robust, medium-sized flies, typically $1/4$ to $1/2$ inch long.
- **Coloration:** Characterized by a gray thorax with **three prominent black stripes** and a distinctive, silver-gray abdomen with a checkered or mottled pattern.
- **Eyes:** Large, reddish-brown compound eyes.
- **Larvae:** The larvae (maggots) are creamy white, cylindrical, and tapered toward the head end.
Distribution and Habitat
Flesh Flies are cosmopolitan, found globally. Their habitat is diverse, including decaying organic matter, dung, carrion (dead animals), and food waste. They are particularly attracted to decaying meat and feces due to the high protein required by their developing larvae. They are common nuisance pests near garbage dumps and livestock areas.
Behavior and Conflict
Flesh Flies have a rapid life cycle and are unique in their reproductive behavior. They typically deposit **live larvae** (larviposit) directly onto the food source (carrion or filth), bypassing the egg stage. This gives their larvae a head start over competitors.
The conflict with humans arises from two primary roles:
- **Disease Vector/Contamination:** They are mechanical vectors for disease, contaminating food surfaces with pathogens carried on their bodies after feeding on filth and carrion.
- **Myiasis:** Certain species can cause **myiasis** (infestation of living tissue) in animals or humans, typically attacking open wounds or ulcers, though some species may infest healthy tissue. This requires veterinary or medical attention.
- **Forensic Entomology:** Due to their predictable arrival on carrion, forensic entomologists use Flesh Fly larvae development stages to help estimate the time of death (Post Mortem Interval).
Management and Prevention
Control focuses on source reduction and sanitation.
- **Sanitation (Key):** Immediately remove and properly dispose of all dead animals, pet feces, and decaying food waste. Ensure garbage containers are tightly sealed and emptied frequently.
- **Exclusion:** Screen windows and doors tightly to prevent adult flies from entering homes and food preparation areas.
- **Trapping:** Sticky traps and jar-style fly traps baited with meat or fish can reduce local adult populations.
- **Chemical Control:** Residual insecticide sprays can be used on outdoor surfaces where flies rest (e.g., garbage containers, shed walls), but chemical control is secondary to sanitation.
Conservation and Research
Flesh Flies are studied extensively in forensic entomology and pest control. Research focuses on their population dynamics and the specific chemical cues they use to locate carrion, aiming to improve trapping and monitoring techniques.