Believe It or Not!
For those of you who have seen any of the Alien movies, you’re familiar with the alien’s chest bursting form.
That cute little guy is an endoparasite, at least for this part of his life cycle. Endoparasites live within their hosts, feeding off of them from within. Parasitic relationships, even with endoparasites, usually aren’t this traumatic. Think of tapeworms. Those guys are endoparasites, too.
There are, of course, a number of very traumatic endoparasites. One of them is a tiny little fly.
Unlike the aliens mentioned above which can use just about anything of sufficient size as a host, the Pseudacteon phorid flies have a special relationship with ants and only ants.
Female flies hover over ants and lay eggs in them. When that egg hatches, the tiny fly larva crawls through the body of the ant up into its head. Over time it grows and develops, feeding on the ant’s body. It begins to change the ant’s behaviors, causing the ant to walk away from the nest and any hive mates that might potentially kill it. As the ant has its brain slowly devoured, it begins to wander aimlessly. After a while, possibly weeks, the ant dies and its head come clean off.
Inside the head, the fly finishes its development. Once it’s fully grown, the young phorid fly makes its escape, bursting forth from the head and flying off.
This fly is in the middle of crawling out from a disembodied ant head. The circle of life continues.