Sooty little sewer fly
You creep me out, I cannot lie
While sitting down to take a pee
I spy you perched there, judging me
And while I know you’re just a bug
Your attitude seems rather smug
Well camouflaged to look like ash
You think I cannot briskly smash
You on the tile and then we’ll see
Who rules the bathroom, you or me
But as I look around I find
I am outnumbered by your kind
You have a lot of little friends
Whose sinister aplomb portends
That maybe I should think this through
Before my swatting starts a coup
And so you’ll live another day
But mark my words, I’ll make you pay
To facilities I will complain
Please, someone clean this filthy drain
Let’s face it, sewer flies, also called drain flies or moth flies are creepy. Where do they come from? What is their ecological niche?
For those of you that like to geek out, the common drain fly has the following scientific classification:
Note they are in the order Diptera which are the insects known as the true flies. And of course I laugh at their genus Clogmia as in “clogged drain”. Get it? Now you can’t forget it!
There are over 3,000 species of drain flies worldwide but most are found in the tropics or hot and humid environments and for anyone who hasn’t had the pleasure of seeing these little guys up close and personal, they are a small delta shaped fly –about 4-5 mm with fuzzy dark bodies, wings and antennae which give them a moth-like appearance. Their wings have simple venation and may have lighter or white spots. Their flight is slow and erratic, almost like stealthy hopping but hard to track with the eye so they appear to land out of thin air.
The reason they are often found in bathrooms is because they reproduce in drains that are infrequently used or dirty. They love the slime layer that forms on stagnant water or wet organic matter such as sewerage, grease or compost piles. So they are important decomposers that feed on organic buildup and the good news is most moth fly species are non-biting and are not known to carry disease (I merely jest in my video for entertainment purposes).
Drain flies live approximately two weeks but can reproduce every 48 hours. The females can lay up to 100 eggs in the organic layer of a drain which then hatch in about two days. The larval stage then lasts 8-24 days with 4 instars (their rate of growth is temperature dependent) and the pupal stage lasts 20-40 hours after which the adult fly emerges. This is why you usually see a swarming of numerous drain flies in a bathroom (shudder).
While you can get rid of them using spray pesticides, an easier way to eliminate them is by pouring boiling water down the drain every day for about a week. If a drain is accessible clean it of any organic matter. You can duct tape the drain at night to catch any survivors that might try to escape. Bwahahahaha, who’s afraid now?
Hey, please check out and follow my new YouTube video link: Sewer Fly
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