2021-11-27

Do flies really “vomit” when they stay on food? Scientists answer for you

By yqqlm yqqlm

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e5daa9be91e1e07 - Do flies really "vomit" when they stay on food? Scientists answer for you

of the more than 110000 known fly species, most have no teeth, so they can’t chew solid food. Their mouthparts are like a soft straw. Once they stay on your food, they need to release digestive juice and liquefy the food into pre digestible and sippable “soup” that they can swallow. In short, some flies feed on liquids

in order to fill their stomachs with more food, some flies try to reduce the liquid in what they have eaten. They ruminate food into bubbles of vomit to dry it slightly. Once some water evaporates, they can eat this more concentrated food

humans do not need to do all these spitting and ruminating actions to obtain nutrients from our food. But people do produce a digestive juice in saliva, an enzyme called amylase, which pre digests some sandwich bread when you chew. Amylase breaks down the starch you can’t taste into monosaccharides such as glucose you can taste. That’s why the longer you chew, the sweeter the bread will be

when a fly lands on your sandwich, it may not be the only thing it landed on that day. Flies often appear on disgusting things, such as dustbins or rotten food, which are full of microorganisms. These germs can take a “free ride”, and if the flies stay long enough, they will come to your food. This is more dangerous than their saliva because some microorganisms can cause diseases, such as cholera and typhoid. But if the fly stays for no more than a few seconds, the chances of microbial transfer are very low, and your food may be fine

vomiting and spreading diseases on food sounds disgusting, but flies are not all bad things. The next time you look carefully outside, you may be surprised at how many flies go to the flowers to collect honey. They are an important group of pollinators, and many plants need flies to help them reproduce. Flies are also a good source of food for frogs, lizards, spiders and birds, so they are a valuable part of the ecosystem

some flies also have medical uses. For example, doctors use maggots — the young, immature form of flies — to remove decaying tissue from wounds. Maggots release antiviral and antibacterial juices, which help scientists create new ways to treat infections

more importantly, you may have seen that fruit flies flying around mature bananas in the kitchen are very valuable in biological research. Biomedical scientists from all over the world study fruit flies to find the causes and treatments of diseases and genetic diseases. In the laboratory, scientists study what the world looks like in the eyes of insects and how they use vision to fly. This knowledge can inspire engineers to build better robots