They deal with this by retreating to cooler spots when the temperature becomes uncomfortably hot. But research suggests that if you put enough maggots in a confined space and wait, eventually the temperature will rise to the point that they’ll start to die—somewhere between 104F° and 122F°.

But research suggests that if you put enough maggots in a confined space and wait, eventually the temperature will rise to the point that they’ll start to die—somewhere between 104F° and 122F°.

Without warm, secluded shelter, flies can’t survive freezing temperatures. Most common flies can’t hibernate, either, which means they need a shelter where they can access food. They’ll work their way into the rotting food to lay eggs and feed continuously.

A dormant maggot can survive surprisingly cool conditions. In lab experiments, they have endured temperatures as low as -60 °C with no consequences. Many cold-tolerant animals avoid freezing solid by stocking up on molecules with low freezing points.

(ProTip: asking a reference librarian to help you determine the combustion temperature of fly maggots really won’t go well.) We know from past research on sweltering maggots that temperatures up to 50ºC (122ºF) can be generated. There is variation from species to species, but thermal death occurs between 40 and 50ºC.

Under normal conditions, housefly eggs take around 20 hours to hatch into larvae (maggots). But when the temperature hits 99 degrees Fahrenheit, those eggs can hatch in less than 8 hours. And the eggs can mature from larvae to pupae to adult flies in as little as four days in extremely hot weather.

Using lime or lemon juice will kill maggots. Sprinkling a large amount of salt over them also does the trick. Strong vinegar or boiling water will kill them as well.