Why do flies rub their legs together?


โ€‹

Why do flies rub their legs together?

๐Ÿ““ The short answer

Flies rub their legs together to clean off dust, dirt, moisture, and pollen that can interfere with their senses. Staying clean helps them fly, avoid infections, an taste with their feet.

๐Ÿ“š The long answer

You've probably spotted a fly rubbing its little legs together and wondered what that's all about.

The options run through your head (memes linked for illustrative effect):

Although it's impossible to rule out world domination, grooming is the reason why flies rub their legs together.

In fact in 2014, researchers purposefully covered flies in dust (rude) and then observed their cleaning routine. They found that a fly might spend more than 20 minutes methodically removing dust from its head, wings, back, and legs.

But for an animal that spends a lot of its lifespan hanging around poop, why are they so concerned with staying clean? Let's dig into the reasons why flies groom themselves:

Reason #1: Flies are trying to maintain good flying performance

Flies fly. To fly well, they are loaded up with touch- and movement-sensitive receptors on their legs and other parts of their body (which also help them avoiding your swatting).

These receptors must be kept free of dirt, dust, pollen, and moisture in order for them to work effectively for flight. Flies use their hairy legs to clean their head, wings, and other legs. Cleaning is part of their pre-flight checklist.

Reason #2: Flies are trying to prevent illness

The bristles on their legs can also attract deadly molds and fungi. Constantly keeping their legs clean helps to maintain good health.

Reason #3: Flies are cleansing their palate

We humans like to think we're special because of our fancy opposable thumbs. But flies have something we don't: The ability to taste with their feet.

Flies walk around tasting for their favorite foods. (Fun fact: Fruit flies don't eat fruit. Instead they eat the yeast that forms on rotting fruit, which is why they tend to show up when you've let your fruit go too ripe.) Once their taste receptors have detected something tasty, they regurgitate saliva from their stomach to break it down into liquid. Without teeth, flies drink their food by sucking it up with a straw-like part of their mouth.

If their taste receptors get clogged with dust or dirt, they won't be as able to find their next meal. Cleaning their legs is essentially a fly's way of cleansing its palate.

Female flies also rely on their taste receptors to identify the best place to lay their eggs. Mom life! (P.S. Happy belated birthday to my mom! ๐ŸŽ‚ โค๏ธ)

---

Thanks for reading this week's newsletter! If you have any thoughts, questions, or favorite GIFs, my inbox is always open. Just hit reply to send me a note! :)
โ€‹

All my best,

โ€‹

โ€‹Sources for this week's newsletterโ€‹



๐ŸŒ Wikipedia article of the week

โ€‹Moberlyโ€“Jourdain incidentโ€‹

"The Moberlyโ€“Jourdain incident ... is a claim of time travel and hauntings made by Charlotte Anne Moberly (1846โ€“1937) and Eleanor Jourdain (1863โ€“1924). In 1911, Moberly and Jourdain published a book entitled An Adventure [which] describes a visit they made to the Petit Trianon, a small chรขteau in the grounds of the Palace of Versailles, where they claimed to have seen the gardens as they had been in the late eighteenth century, as well as ghosts, including Marie Antoinette and others. Their story caused a sensation and was subject to much ridicule."


๐Ÿ“š Did you know all affiliate revenue from book purchases is donated to charity?

Today You Should Know is an affiliate for Bookshop, an online book marketplace that supports local, independent bookstores.

I frequently update the Today You Should Know recommended reading list with my favorite fiction and nonfiction books. And I donate all affiliate proceeds to Room to Read, a leading nonprofit for children's literacy and girls' education across Asia and Africa.

It's a win-win-win: you get to read a book, small bookstores get some business, and money is donated to a great cause.
โ€‹


๐Ÿ‘€ Catch up on other curious questions

P.S. ๐Ÿค” Do you have a question for the newsletter? Click here to submit your question (or reply to this email!)


Refer friends, earn rewards!

Have a curious friend who'd love to learn more about the world? Share the link below and you'll receive rewards for referring people to Today You Should Know.

๐Ÿ“ง (1) Refer just ONE person and receive a special "Five Fast Facts" edition of the newsletter.

๐Ÿ“ฃ (5) Refer five people and I will shout you out in the newsletter.

๐Ÿ“š (10) Refer 10 people and I will ship you a free, surprise book on an interesting topic.

Thanks for spreading the word!

[RH_REFLINK GOES HERE]

facebook twitter linkedin email

P.S. You have referred [RH_TOTREF GOES HERE] people so far.

๐Ÿ’ก Today You Should Know

Learn something new every Friday. Join 2,000+ nerds and satisfy your curiosity one question at a time with topics including science, technology, history, and more.

Read more from ๐Ÿ’ก Today You Should Know
february 29

Why do we have leap years? This question came from a reader submission (thanks Shi So!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question ๐Ÿ““ The short answer Leap years exist because a full orbit around the Sun takes 365.242189 days, so we add extra days to keep our calendar aligned with the seasons. The Gregorian calendar uses specific leap year rules to stay closely synced with the solar year, skipping three leap years every 400...

George Clooney

What causes dark circles under your eyes? This question came from a reader submission (thanks Aastha!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question ๐Ÿ““ The short answer Dark circles under the eyes can result from true hyperpigmentationโ€”caused by excess melanin, iron deposits, skin thickening, or visible blood vesselsโ€”or from shadowing effects due to changes in under-eye volume like hollowness or puffiness. ๐Ÿ“š The long answer Perhaps...

a large group of cell phones

What made old Nokia phones nearly indestructible? This question came from a reader submission (thanks Jana!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question ๐Ÿ““ The short answer The Nokia 3310 was nearly indestructible thanks to its rugged double-shell plastic design, compact build, recessed screen, non-glued components, single Printed Circuit Board, and a company-wide emphasis on durability and reliability. ๐Ÿ“š The long answer As...