Yesterday, while in my kitchen, a housefly flew by. Without thinking, I swatted it out of the air with a kitchen towel. It bounced off the wall and lay on the floor motionless. I thought to myself, “Cool. I’ve got a new macro lens for my camera, I’ll use it on the fly and see what I can see.”
When I went to move the fly, it was still moving, so I stuck it with a wooden skewer to kill it, and so I could move it outside. But when I stuck it, some of its guts squirted out its side. As I cleaned it up, I noticed its ‘guts’ were trying to crawl away. It’s ‘guts’ were actually a mass of tiny maggots. For an instant I thought, “gross, it was pregnant.” But then I realized flies don’t lay live maggots, they lay eggs.
So why did this fly have live maggots inside? I was thinking maybe some kind of parasite, but I can’t find any info on a parasite like this. It seems they often have a kind of mite under there wings, which it seems to have here.
There is also a wasp which lays an egg in the pupal case, where it feeds on the pupa.
For those interested, here are some photos of one maggotcrawlingout.
That is what I assumed, but I was surprised I couldn’t find anything on the internet. I though they must be rather common. I wouldn’t expect that the first fly I skewer since I was 10 had some unusual condition.
The volume of maggots seemed rather large compared to the size of the fly. There were at least 20-30 of them in the first blob that came out, and I don’t know how many more were still inside. It seems surprising that the fly was still flying with all of those in there if they were eating their way around. Flies aren’t complicated creatures, but still…
Your assumption is incorrect. Many flies are ovoviviparous, meaning that the mother retains the eggs inside her body until they hatch. The mother then gives birth to live maggots.
How remarkably fascinating. Plus I learned something new about flies.
Those are some keen pictures too. What kind of camera/lens is that? I am now inspired to attempt my own pictures of flies, their wingpit mites, and other small wonders.
Oh my god, I’m horribly disgusted and utterly fascinated at the same time! It’s kind of like reading an eight page Pit trainwreck but without the gossipy voyeurism.
I’m not clicking the links. I don’t want to see an eviscerated fly if it was big enough to run a skewer through it.
