I thought I’d follow up my recent column regarding fungus on bark mulch with something equally distasteful so get ready! The other day, because it was badly in need of emptying, I took my compost bucket out onto the porch. It’s approximately a foot square, has a lid and is made of black plastic. I bought it at IKEA a few years ago since my previous metal bucket had rusted through. There is always moisture in the bucket. Condensation drops are usually coating the inside lid and very often mold and/or fungus starts to grow in the mixture of coffee grounds and kitchen scraps my partner and I throw in there. I know that’s all a part of it doing what it’s supposed to be doing. It gets tossed in my outdoor compost pile whenever it gets full. Usually every couple of weeks.
Aside from this natural process of breaking down organic matter, the bucket often has fruit flies in it. Now, as I said, the bucket has a lid and it’s always covered except for those brief seconds when I’m tossing something in there. How do the flies get in there then? I had long suspected that fruit flies are brought into the house right on the very fruit you either just picked or bought at the market. But, still… don’t most people rinse their fruit and vegetables before eating or preparing a meal? Shouldn’t that get rid of any ride-along little fruit flies? Well, the answer to that is yes. Do you see where I’m going with this?
Indeed, as thorough as you might be washing your fresh fruits and vegetables, fruit fly eggs can’t just be washed off since they’re not typically found on the surface. The female fruit fly (drosophila melanogaster) lays her eggs just under the surface skin of fruits and vegetables. Unless you peel the skin off or cook the produce, you’re going to wind up ingesting those eggs. Yuck! Think about that for a moment. What do fly eggs turn into next during their cycle of life? Maggots!
Before you go dashing to your fridge to toss out every bit of edible produce you’ve got in there, eating fruit fly eggs, in general, is not that big of a deal. The stomach acids our body uses to break down foods is pretty darn harsh and typically kills any live eggs we might have accidentally consumed. According to an article quoted about intestinal myiasis at findananswer.com, finding live fly larvae in human stool is very rare. It has occurred but usually not with fruit fly larvae. Most live larvae that were found were from the common house fly. Even if that fruit were a little riper and the larvae had hatched, your stomach acid is typically strong enough to take care of those too.
Back to my compost bucket. I left it out on the porch overnight and went to dump it the next day. Inside that lid, it looked like a tomato had exploded and left tomato seeds everywhere. I’d seen this before and had a suspicion. These little “seeds” I was able to identify by taking a photo of them, then zooming in on them and comparing to online photos of… fruit fly larvae! Yes, it turns out fruit flies have three larval stages and this one’s called the pupae… right before they finally emerge as fruit flies. If you wait a little longer, they become translucent and you can actually see their big eyes peering through the membrane. Again, a big yuck! I have to admit, though, I did feel just a little guilty washing them down the drain when I brought the bucket back inside to clean it. I actually had to use my hand to rub them off since they had pretty good sticking power. I would doubt the pupas would survive inside the septic tank. A least I hope they don’t. The poor things. Imagine growing up underground in a septic tank!