What is a significant factor for the population growth of flies?

The population growth of flies is significantly influenced by the availability of food. Flies, particularly common species such as houseflies, thrive in environments rich in organic matter and waste. Their larvae require a suitable food source to develop, typically compost, decaying fruits, or other organic material where they can feed and grow. When food sources are abundant, flies can reproduce more rapidly, leading to an increase in their population. In contrast, even with suitable environmental conditions such as optimal temperatures and humidity, a lack of food can severely limit their capacity to grow and sustain their population. Thus, food availability plays a crucial and direct role in promoting and sustaining fly populations.