Following my ever-freaky blog entry about killer fungi (Cordyceps), I recently had the opportunity to see a fully-developed larvae of a Botfly, another one of nature's freaky creatures that will creep out just about anyone! So of course, I have to write about it (if you think about it, it’s fascinating as well).
What’s so freaky about this fly?
The botfly (family Oestridae) is a parasitic fly in which its larvae require a soft, protective “home” in order to develop. Botflies, however, choose the skin of animal hosts, including humans, as the perfect place to for their maggots to develop. Female bot flies lay their eggs on their vector, most often mosquitos but also other species of flies and a species of tick. When the vector bites the host, the egg or hatched larvae is transferred onto the skin of the host, which then attaches and buries itself into the skin. There it creates a home for the next several weeks as it grows. Botfly maggots anchor themselves in their “home” with rows of hooks around its body, and two fang-like mandibles. They feed on the blood and tissue of their hosts. They require air through a breathing hole in the skin, and their chamber is maintained and cleaned by an antiseptic secretion. Botflies do not kill their hosts, and after the larval development, the maggot will drop from the skin of its animal host and pupate in the ground. Botflies are particularly common in mammalian hosts in warm, tropical regions, but temperate regions are not out of the question either, as deer, caribou and livestock are often used as hosts.
Wait, it gets freakier… there is a human botfly! Dermatobia hominis is a species that will seek out human hosts. I have a number of friends that have had botflies during their field seasons here in the Neotropics. Most people try to remove them early on in their development stages, as they can cause significant pain with those hooks and mouthparts as they get larger. Generally, only hard core entomologists are willing to try to let a larval botfly grow to full term.
This week, I met a man with a human botfly in his scalp. When he told me that it had been there for over 70 days, I was surprised, this creature must have been huge and getting ready to pupate. I had to see it! By this point in its development, they can cause extreme pain to the host, and Craig could attest to that.
So the night before, we treated it with an herbal compound paste, which essentially blocks its breathing hole and causes it to relax its muscles. The next morning, they squeezed the maggot out. It was huge, about the size of a peanut. It must have been just days away from leaving its human “home”. The intact maggot was placed in a jar of alcohol—a rather interesting souvenir to take home from the tropics!