Final answer:
Blow flies are the most commonly found fly species on dead bodies, and forensic entomologists use the life stages of their maggots to help estimate the time of death. The attraction of flies to decaying flesh is predominantly due to the odor of polyamines generated during decomposition.
Step-by-step explanation:
The fly species most commonly found on dead bodies are blow flies (family Calliphoridae). These flies are typically the first to arrive on a cadaver and are known for laying their eggs on decaying flesh, where their larvae, or maggots, will subsequently feed. Forensic entomologists can determine the time of death by examining the developmental stages of maggots recovered from cadavers. This process is part of a field of science called forensic entomology, which plays an important role in crime scene investigations.
Forensic entomologists rely on their knowledge of insect life cycles to provide estimations of various important timelines at a crime scene. The presence of other insects, such as dragonflies, termites, beetles, ants, cockroaches, grasshoppers, crickets, and caterpillars, can also provide valuable information, but it is the blow fly that is most closely associated with cadavers.
Conducting experiments on how flies are attracted to certain odors, scientists have developed a hypothesis that flowers sprayed with polyamines such as putrescine and cadaverine, substances produced during the breakdown of proteins in decaying animals, could attract flies despite their visual cues. This supports the background knowledge that the odor of decaying flesh is a key factor in attracting flies—a characteristic used by some plants, such as the corpse flower or voodoo lily, to lure fly pollinators.