Food Waste Episode 3: Flies

From piles of food waste in the South Korean military, entire ecological chains quietly form, with JJAM sitting at the center of the system.The first episode of this series introduced JJAM—the slang word for food waste—and looked at the negative effects of its massive volume, along with a simple solution. The second episode focused on an animal that had grown strangely dependent on JJAM: the cat, famously nicknamed the “JJAM-TIGER” in the military.

Today’s episode is about another creature that thrives just as enthusiastically on JJAM—flies.

To me, flies were just… flies. That was until I spent an entire day cleaning the cafeteria during my military service. By the end of that shift, I felt like I had seen every fly I would ever see in my lifetime. They swarmed everywhere—walls, ceilings, food waste bins—forming dense clouds that felt less like a hygiene problem and more like a tiny ecosystem in motion. With nothing else to do but clean and suffer, I started watching them more closely.

One thing I noticed was how flies constantly rub their “hands” together. It looks pointless, but it’s actually self-grooming. Flies clean their legs and mouthparts to keep their sensory organs functional. Their chemoreceptors—used for smelling and tasting—get clogged easily, and if they’re dirty, flies can’t tell food from danger. So even when they look idle, they’re basically doing maintenance work.

Flies are drawn to food waste thanks to their incredible sense of smell. As food decomposes, it releases volatile organic compounds (VOCs) like ammonia, hydrogen sulfide, and fatty acids. To us, those smells are unbearable. To flies, they’re basically GPS signals. These compounds don’t just lead flies to food; they also guide them to perfect egg-laying sites. Houseflies (Musca domestica), for example, lay eggs directly in organic waste, where the larvae—maggots—can immediately start feeding.

Summer makes everything worse. Warmth and humidity speed up the fly life cycle dramatically. At around 25–30°C, a fly can go from egg to adult in just 7 to 10 days. A military cafeteria in midsummer, surrounded by JJAM, is basically a luxury fly resort. If waste isn’t handled quickly, the population explodes before you even realize what’s happening.

Because of this, flies aren’t just annoying—they’re bioindicators. In places like the military, where many people share meals and facilities, flies are a warning sign. Their presence hints at hygiene problems and potential risks like food poisoning or disease transmission. The flies, however, did not seem concerned. No matter how much we cleaned, they kept coming back. Sometimes it felt like there were more flies after cleaning than before. So we tried everything.

First came the electric fly zappers—UV light traps that lure flies in and electrocute them. Flies are especially sensitive to UV light around 350–370 nm, which makes these devices disturbingly effective.We also kept the kitchen air-conditioned at all times. This wasn’t just for food safety. Flies are ectothermic, meaning their activity depends on temperature. Below their favorite range (around 27–32°C), they slow down, move less, and reproduce less. Cold air became our silent ally. Finally, there were homemade fly traps—vinegar, sugar water, fruit peels—anything that smelled fermented and irresistible. Once flies went in, they didn’t come back out. It was simple, low-tech, and surprisingly effective.

We fought hard. And yet, watching flies stubbornly reappear day after day, one thought kept coming back to me: as long as JJAM exists, flies will too. They are the most persistent survivors in this strange military ecosystem.

Now, I’ve been in the military for over a year. I’ve accumulated enough JJAM—the seniority kind—that I no longer clean the cafeteria. Last summer, though, I was a new recruit, low in rank, sweating with a mop in my hand. Today at lunch, I saw a group of fresh recruits cleaning the dining hall, exhausted, swinging fly swatters like swords. And suddenly, that summer came rushing back to me.

There’s a lot I couldn’t fit into this essay—flies come in many varieties, after all. The ones I talked about today belong to a group called Cyclorrhapha, the most common type. But honestly, taxonomy aside, one thing is clear: ranks change, seasons pass, soldiers rotate—but the flies keep their post.