Flies belong to the Diptera order, Brachycera suborder. Among the various species of flies in existence, the main one is the house fly.
The adult fly is 6-7 mm long, with a wingspan of 13-15 mm. The optimal temperature is that in the summer of approx. 30°C, which leads to greater reproductive activity: at this temperature, the complete cycle can take place in 8-10 days.
When reproducing, flies are attracted by piles of rubbish containing decomposing organic substances, suitable for feeding their offspring and, in particular, by rubbish dumps and dung heaps. In any case, they avoid laying their eggs on material that is not sufficiently warm and humid, i.e. such as to ensure normal development of the larvae that cannot thrive in a dry and excessively cold environment.
The complex mix of gases and odours of the various substances released during decomposition appears to exert a special attraction on egg-laying females, but there are certainly other factors of attraction such as water vapour and high temperature.