Why me? As I’ve been wondering why these dratted pests seem to have a particular interest in my flesh, the questions have kept buzzing around in my head. Why does it have to be this way? Do flies serve some purpose in the scheme of things? Are flies just an annoyance or do they really cause problems for people? I decided to do some research. This is what I came up with.

How Flies Help Humans

Maggot Debridement Therapy

Believe it or not, common house flies, or Musca domestica, can help us out. One way is through Maggot Debridement Therapy. This is a process whereby doctors insert fly larvae, or maggots, into wounds and bone infections.

Here, the maggots ingest the dead tissue and disinfect the areas with ammonia and calcium carbonate which are naturally secreted from their bodies. This kind of treatment was used during the Civil War and in the 18th century by Napoleon’s surgeons.

Flies as a Forensic Tool

Forensic scientists can approximate the length of time a person has been deceased by looking at the maggot activity in a dead body. Assuming the house fly lands relatively quickly after death, scientists will estimate that eggs will hatch 8 – 24 hours after the fly lands on the dead body. The pupae stage follows and adults appear from 3 – 6 days later.

Flies and Disease

Scientists have proven that several diseases can be caused by the common house fly. Throughout recent history it has been said that cholera, dysentery, typhoid, and tuberculosis have been spread through the common fly. That sounds serious, but not as serious as this.

Flies as Warfare

During World War II, the Japanese used Yagi bombs, or “maggot” bombs to eventually kill 410, 000 people in the areas of Baoshan and Shandong. The Japanese dropped bombs that seemed to be duds because upon impact, the casings opened with no explosion.

However inside were adult flies and a yellow waxy substance which covered the flies as they escaped the casing and flew far and wide. The substance was filled with cholera bacteria.

Everyday Contact with House Flies

Since people aren’t dropping like flies from their exposure to this common pest, I had my doubts about their present dangers to humans. I decided to take a break from my investigative research and attend the barbecue of my friend. But here, I will continue to observe the creatures in their natural habitat and take mental notes as they may come to me.

Why Flies Land on Humans

I am sitting, minding my own business at this barbecue. I have been swatting the flies ever since I got here. Some of the food has come out and yes, the little monsters have been landing on all the goodies, but they haven’t left me alone.  What is it about me?

I swat at another one of the little dark air force, and I look over to the guy across from me at the table. He is sitting serenely, with a satisfied smile on his face, watching the party guests getting their food, talking, laughing. “Hey! ” I say. “Why aren’t the flies landing on you but they’re eating me alive!”

My table mate calmly turns to me and suggests, “Maybe you’re hot.”

“I beg your pardon?” I retort.

“Oh, I mean that you might be perspiring. It’s pretty warm today and I see a few beads of sweat on your brow.”

Only mildly insulted, my curiosity leads me to ask, “Flies like sweat?”

What Flies like to eat

“Oh yes, sweat, carbon dioxide, maybe a bit of food substance left on your arm. They really seem to be after your arms.”

“How do you know all this?” I ask.

“I’m an entomologist actually. I am friends with the hosts of the party through the University. So yes, I know a fair amount about flies.”

“Well, that’s great! Uh, I should probably go and wash my arms.”

“That may not do it. They may prefer the soap you use. It can depend upon what you’ve been eating as well. Starches, salts, sugars attract the Bracycera…”

“Brock kiss what?”

“The scientific name of the common house fly or filth fly,” said the entomologist.

“Nice. Filth fly, you call it?” I said as I swatted another.

“They probably got that name from the substances they prefer to eat and lay their eggs on.”

“Oh, don’t tell me.”

The entomologist went on. “Dog poop, garbage, rotting food, dead animals, are their delicacies.”

“You don’t say,” I said trying not to puke.

“There are at least three kinds of filth flies: house flies, blow flies, and fruit flies. Blow flies lay their eggs in the bodies of dead animals which make the bodies have a bloated appearance. Fruit flies love sweet sticky substances and often lay their eggs in drains or disposals.”

Flies as Germ Carriers

“Most people think that cockroaches are a worse germ carrier, but flies have them beat by far,” said my entomologist.

“Yeah, I can just see it, they hop around on their favorite whatever and it gets all over them.”

“Pretty much. And they can transfer the germs in just one second. They land on you or on the food at a picnic and voila.”

“So they’re eating when they land?”

“Yes, they have a proboscis, a trunk like mouth which they use to vomit enzymes which then break down the food into a liquid which they can then slurp up,” He made an unpleasant slurping sound to illustrate his point.

By now, I was looking for somewhere to throw up. “Excuse me,” I said. I wandered around the yard, looking over at the burgers and hot dogs which were now being set out. I overheard a woman commenting on the flies.

“They’re not so bad. There’s a nice breeze today. I don’t mind a few flies, better than mosquitoes.”

A dad was getting a hot dog for his child. “Don’t mind the flies, honey. Just sing the old song,” He broke into his own version of “Shoo Fly Don’t Bother Me.”

I was beginning to feel a little better. I stumbled back to my table. The entomologist was still there. In front of him was a plate with a hamburger on it. “Here,” he said. “While you were gone I took the liberty of getting you a burger.”

“Don’t be too alarmed,” he said. Dr. Maggie Hardy, an entomologist from Australia, actually believes that flies are cleaner than other studies suggest.”

He placed the hamburger in front of me. A fly landed on top of the bun. I picked up the burger, walked over to the trash, and dropped it in. Looking over at my entomologist friend, I gave him  a wry smile and waved a parting goodbye.

We hope you enjoyed this article. For more information on scents that attract flies vs scents that repel flies, click here.

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