Odors that repel and disgust us, seem to be particularly appealing to flys. A fly can be distinctly identified because it only has two wings, while all other flying insects have four. Flys are fast flyers - almost flight acrobats - which can even compete with the dragonflies.
The common housefly (Musca domestica) lays its 60-200 pearlescent, elongated eggs into clumps of dung, carrion and rotten food. The maggots hatch after 24 hours, pupate into little brown barrels and after only 10 - 14 days swarm out as fully developed insects ready to reproduce. The reproduction is so dramatic that in one year a single pair of flys could have many trillions of offsprings - if they didn't have any natural enemies.
A close relative, who also resides in many homes is the blow and hum fly (Calliphora erythrocephalla). It also lays its eggs eggs into decaying or rotting vegetables and animal substances.
Flys transmit decay provoking agents and germs onto food and are a severe problem especially for the food processing industry. They are partially responsible for the spreading of the gastric ulcer pathogen (Helicobacter pylori), and according to the opinion of researchers transmit dangerous bacteria that can cause an inflammation of the gastric mucosa and lead to gastric cancer in humans. Dr. Peter Grubel, a scientist from Boston, says that a single fly can carry around up to 6 million bacteria on and 40 million bacteria in its body. A fly is, so to speak, a widebody aircraft for microbes.
But even flys serve their purpose in nature, because they hold a firm position in the food chain of other animals.
But we assign them to the place we choose, by protecting us and our food supply from them with NESENSOHN fly-screens.