Many fly species eat meat, but they cannot chew or bite it like humans. Common house flies and their relatives are equipped to handle only liquid meals. Therefore, any solid food, including meat, must be processed before consumption. This specialized feeding mechanism allows various fly species to utilize decaying protein sources, which is significant to their ecological role.
How Flies Consume Solid Food
Flies rely on external digestion to access nutrients locked within solid meat. Lacking jaws or teeth for chewing, the fly uses a sponge-like mouthpart called a proboscis. When encountering a solid substance, the fly first deposits a mixture of saliva and digestive enzymes onto the surface.
These powerful enzymes begin to break down the complex organic material outside the fly’s body, effectively liquefying the solid food. This process transforms the meat into a digestible, nutrient-rich “soup” within seconds. The fly then uses the spongy tip of its proboscis to soak up the resulting liquid, which is drawn into its digestive tract.
Species Drawn to Meat and Carrion
Necrophagous species of flies actively seek out and feed on carrion (decaying flesh). The most prominent are the Blow Flies (family Calliphoridae) and the Flesh Flies (family Sarcophagidae). These species are primary colonizers of dead animals, often arriving within minutes or hours of death to lay their eggs.
This rapid arrival is driven by an incredible sensitivity to specific chemical signals released during the initial stages of decomposition. As tissues break down, they release volatile organic compounds (VOCs). These odors, which are undetectable to humans, act as powerful olfactory cues, attracting female flies from miles away to an ideal site for their offspring.
The Role of Flies in Decomposition
The appetite of these flies and their larvae for meat plays an important role in global ecosystems by accelerating the breakdown of organic material. These insects are nature’s recyclers, preventing the buildup of carcasses and quickly returning nutrients to the environment. Their tendency to move between decaying matter and human food sources makes them potential vectors for pathogens, transferring bacteria from one meal to the next.
The predictable life cycle of these meat-eating flies is used in forensic science, specifically forensic entomology. By analyzing the species of flies present on remains and the developmental stage of their larvae (maggots), investigators can estimate the Post Mortem Interval (PMI). Since different fly species arrive at a body in a known sequence, this insect evidence provides an accurate biological clock for determining the time elapsed since death.