Life histories of Calliphoridae

Blow flies (Diptera: Calliphoridae) are a family of true flies that play key roles in both ecological and forensic contexts. Blow flies are among the first groups to arrive on a decomposing corpse with the goal of colonizing it by laying eggs; the subsequent maggots emerging from the eggs will feed on the carcass voraciously until all soft tissues are consumed. For this reason, blow flies are incredibly important in the breakdown of organic matter and nutrient recycling; moreover, considering how quickly they are able to reach a corpse after death, they can be considered one of the main pieces of evidence in death investigations. Blow fly’s attraction to carrion and its ability to locate it quickly is mediated by chemical cues released by the carrion itself and by other decomposing organisms (bacteria). Blowflies are holometabolous insects, and their development consists of an egg stage followed by three larval stages (first, second, and third instars), a nonfeeding prepuparial third instar, a pupal stage, and an adult stage. The duration of each stage is strictly dependent on temperature and on other biotic and abiotic factors; since larval development occurs entirely on carrion, the blow fly life cycle can be used to estimate time of death in forensic investigations. This chapter discusses the biology, the development, and the ethology of blow flies, highlighting their attraction to decomposing matter, their development, and their importance in medico-legal entomology.