American in Spain

Musca Mucus (a.k.a. Fly Spit)

August 7, 2007

The other day, I noticed the perfect silhouette and reflection of a housefly, Musca domestica, sitting on the glass table in the kitchen. I watched it for a bit and then went to get my camera. As I looked more closely, it looked like he was eating a breadcrumb. As I was taking these, I realized that my camera really sucks for macro photography. I had to set it on manual focus and then move the camera closer and further from the winged subject to get the focus right. I must have discarded about 30 attempts. (So don't complain about the focus!)


This is the original silhouette. His face and arms look almost human, don't they?


Yes, the table's a little dusty, but what do you expect with the door open letting in all the flies?


Here you can see how red his eyes are. Yes, that's a box of beer reflected in the background.

Then, as I was taking these photos, he proceeded to rub the ball of liquid in his "hands" all over his face and eyes. He then put his hands back up to his mouth and started to cough up another batch. Gross, huh?

The two relevant bits of information from Wikipedia are:

Houseflies can take in only liquid foods. They spit out saliva on solid foods to pre-digest it, and then suck it back in. They also vomit partially digested matter and eat it again.


Flies continually preen themselves, cleaning their eyes with their forelegs and dusting off their legs by rubbing them together. They do this because most of their taste and smell receptors are on the hairs of their legs.

It reminded me that flies really do operate in other worlds, where forces like surface tension, that only matter to us when doing belly flops, are hugely important. Imagine being able to hold a drop of water the size of your head in your hands. According to Wikipedia, it's surface tension that allows flies to defy gravity and walk on the ceiling. There, I hope you've learned a little something about our little domestic pest. I leave you with one of my favorite song verses, about being a housewife (something I'm not unfamiliar with):

There's flies in the kitchen. I can hear 'em there buzzin'. I ain't done nothin' since I woke up today. How the hell can a person go to work in the mornin' And come home in the evenin' with nothin' to say?

- John Prine, Angel from Montgomery