Sheepish Fly

Photo source: Tony

The fly below was spotted in Tasmania. It's a sheep nasal bot fly, which was introduced (much to the joy of the sheep) into Australia. Though they prefer sheep, there are many cases where they've infected humans. Infected, you ask? Here's what I mean:

The adult female fly is active during summer and early fall. Eggs are retained in the body until they hatch. Flies deposit as many as 500 larvae in the nostrils of sheep. The larvae then move up the nasal passages to the nasal and frontal sinuses. The larvae remain in the sinuses for 8 to 10 months and then are sneezed out of the nostrils. The larvae pupate in the soil with the pupal period lasting 3 or more weeks, depending on temperature. Adults then emerge from the pupae and may live as long as 28 days.

Isn't nature lovely sometimes?

Cuterebras

Those of you who enjoyed my previous bot fly posts will love this next one. Megan is a biology student who is earning her keep at a veterinary clinic. About a month ago she had to deal with a rash of cuterebra cases in dogs.

Cuterebras are but one iteration of the bot fly. What's a bot fly?

Photo source: Brittanica
Well, the fly itself is harmless. They don't bite or sting. They do vaguely resemble bees, but they have nothing, ecologically speaking, in common with them. You see, a bot fly (a cuterebra in this case), lays its eggs along the paths or around the dens frequented by small mammals (dogs, cats, squirrels, rabbits, etc.). The hapless animals then either rub up against or ingest the eggs, which then hatch. The newly spawned bot fly larvae travel to a spot just beneath the skin and form a 'nodule'.

These nodules can be sizeable, since the larvae which inhabit them can get upwards of two-inches long. The larvae have cutting teeth that they use to cut a little hole on the outside so they can breathe. Look up 'bot fly' on YouTube for videos of them in people's backs. You won't be the same afterwards.

Photo source: unknown




















If you find a squirrel with cuterebra nodules, don't worry. The larvae will drop out within 30 days and pupate on the ground. The nodule will heal up. You might not be so cavalier, though, if you get infected. If you do, you'll want to cover the hole with petroleum jelly, which will cause the larvae to emerge for fresh air. Then you can grab it with tweezers. But don't squeeze too hard. If it pops or crumbles inside your skin, it can trigger an infection or even anaphylactic shock.

Ugly, people. Ugly. Thanks, Megan.

Cancel My Flight

Pam sent me this article that details the misadventures of one Aaron Dallas, who had recently traveled to Belize. See the maggot-looking insectoids below? You're staring at the five bot fly larvae that were pulled from this poor fellow's scalp. He described it first as if someone were pressing into his scalp with their knuckles, then with a needle, and then with a nail. It was excruciating.

You can read the article for more lovely details. As for myself, I'm going to cancel my flight to Belize and instead stay cooped up in my house, with the doors and windows sealed. And I'm going back to wearing my tinfoil hat.

Thanks for the link, Pam.

Photo from: PostIndependant.com

Move Along

This post isn't for the squeamish. Seriously. If you have an aversion to maggots or parasites, move along.

Phlimm sent me this beastie, and it has made me never want to travel abroad. Behold the bot fly, or rather, its lavae. There are several varieties of this pest, but the one you probably care most about is the one that can end up in you.

What happens is an adult bot fly lays its eggs on a mosquito (why the mosquito hangs around for that, I don't know). Then, when the mosquito lands on its next victim, maybe you, the egg(s) is deposited on the new host. And, ta-da, you end up with a maggot living in your scalp or back (or anywhere the mosquito decided to take a sip).

For the daring, trying searching for 'bot fly' on YouTube. You'll lose your appetite.

Thanks for this monster, Phlimm. The world is a grosser place now.

Photo courtesy: Armed Services Pest Management Board