How Many Flies Are in the World?

It is difficult to determine exactly how many flies are in the world, but scientists estimate there are around 120,000 species. The number may be much higher. The flies are grouped into families and genera, and species within a family may share common lifestyles and habits.

The number of flies on the planet continues to grow exponentially. One female housefly can lay up to 150 eggs per batch, and up to 500 in her lifetime. The eggs are laid on organic materials such as dead leaves, plants, and decaying organic matter. The eggs hatch in ten days, and the larvae eventually pupate in a hard pupal shell. Houseflies can produce up to 12 generations during the summer.

One example of the scale of the fly’s potential is the housefly, which has a population of approximately 190 quintillion. This amount of diversity is unmatched by any other insect. According to Dr. Marlene Zuk, a biologist at the U.S. Department of Agriculture, a single housefly can produce descendants totaling 190 quintillion.

While we humans consider flies pests, they actually play a vital role in the ecosystem. Flies break down decaying matter, releasing organic nutrients back into circulation. Flies do this by increasing the surface area of decayed matter.