April 1st, 2008


Cheese Flies: the insect most frequently found in the human intestine!

Looking for Pecorino cheese at the store yesterday, and not finding it, lead me to reading about its origin online. Which lead me to the Cheese Fly......

[info from Wikipedia:]

Cheese flies are members of the family Piophilidae of flies (Diptera). Most are scavengers in animal products and fungi. The best-known member of the family is Piophila casei. It is a small fly, about four mm (1/6 inch) long, found worldwide. The fly's larva infests cured meats, smoked fish, cheeses, and decaying animals. The larva is about 8 mm (⅓ inch) long and is sometimes called the cheese skipper for its leaping ability - when disturbed, this tiny maggot can hop up to 15 cm (six inches) into the air. Adults are also known as "bacon flies" and their larvae as "bacon skippers", "ham skippers", "cheese maggots", and "cheese hoppers". In Sardinia, Italy the larvae are intentionally introduced into pecorino cheese to produce casu marzu.

If eaten (accidentally or otherwise), the larvae can pass through the digestive system alive (human stomach acids do not usually kill them) and live for some time in the intestines. This is referred to as an enteric myiasis. Cheese fly larvae are a leading cause of myiasis in humans, and are the insect most frequently found in the human intestine. The larvae can cause serious intestinal lesions as they attempt to bore through the intestinal walls. Symptoms include nausea, vomiting, pain in the abdomen, and bloody diarrhea. Living and dead larvae may pass in the stool.

Forensic entomology uses the presence of Piophila casei larvae to help estimate the date of death for human remains. They do not take up residence in a corpse until three to six months after death.

The adult fly's body is black, blue-black, or bronze, with some yellow on the head, antennae, and legs. The wings are faintly iridescent and lie flat upon the fly's abdomen when at rest. At four mm (1/6 inch) long, the fly is one-third to one-half as long as the common housefly. Liopiopila is a typical genus.

The larvae accomplish their jumps by "erecting themselves onto their anus," bending over, grabbing onto the rears of their own bodies with their mouth hooks, tensing their muscles, and quickly releasing the grip. Spring action propels them into the air.
Here is a series of photos illustrating this remarkable behaviour in larvae of the tiny piophilid Protopiophila litigata, commonly known as the "antler fly" (it breeds exclusively on discarded antlers of cervids such as moose and deer):


Prochyliza xanthostoma breeds on rotting carcasses and is highly sexually dimorphic, with males having greatly elongated heads, antennae and legs, relative to females. P. xanthostoma also has spectacular mating and fighting behaviours.
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On the subject of parasites....

[I looked through the archives a bit and didn't see this critter posted..... although mentioned in the comments in this post about giant isopods. My apologies if I'm being redundant.]

When I first saw this, I thought it was fake:

It isn't.

There’s apparently a parasite that eats (and eventually replaces) fish tongues! This parasite, called Cymothoa exigua, snacks on the fish’s tongue until it eats it down to just a stub. But by then, the thing is big enough to replace the fish’s tongue, which it does. The fish is pretty much unaffected by the presence of the parasite, since the “tongue louse” functions like a tongue, but that parasite also gets the pickings of food particles that the fish lunches on.

This parasite was thought to exist solely on the Gulf of California, but a red snapper at a fish market in London was recently found with one: http://animal.discovery.com/news/briefs/20050912/tongueeater.html

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This post, although in Japanese, it worth checking out if you want more gnarly pictures.


Up next? Maybe I'll write about the fish parasite that eats, replaces, and hangs from the fish's eyeball! Anyone posted on that yet?
dart frog


What looks like a cross between a wolf and a zebra?

An aardwolf!!

Like the aardvark, they enjoy eating tasty termites! They are very specialized for this purpose, as 90% of their diet is made up of a single species of termite! They are able to hear the clicks that termite's jaws make as they chew away at their woody food-stuffs, and then the aardwolf comes in and licks them up! They also burrow in holes dug out by aardvarks, which the aardvarks make  while hunting for termites themselves.

Aww, pups

Wikipedia says more about these interesting little things I never heard of until today in my animal behavior class.