Machaca, Man-Killing Moth

In the rainforests of Ecuador you hear about all sorts of amazing animals and fantastic legends. There are bullet ants so-called for their sting feels like you have been shot, and the indigenous Shuar tell a story of an incestuous pregnancy giving birth to a horde of caterpillars. Some of these charismatic animals become central to people’s beliefs and some beliefs exaggerate those animals. So what was I to think when I hear the story of a moth that has a fatal bite and sex is the only cure? Local legend or new to science?

The initial information given was from a Shuar sharman. She explained that the machaca (Spanish for ‘crush’), a strange looking moth with a bulbous head, bites you in your sleep and in the morning you awake with a fever. Hospitals do not have an antivenin and only treat the effect of the fever rather than the cause. The one cure is to have sex, for if you do not you will die in a matter of days. There were said to be a few species of moths that look very similar – which are harmless – but it is the specie that lives upon an unspecified tree used for incense that is the killer.

I investigated.

The machaca is not a moth but a genus of fulgura.

In the Morona-Santiago province of Ecuador, an Amazonian area which boarders Peru, every person spoken with knows this moth. There is indeed a recognised genus of insects known as machaca, the fulgora, which firstly are not moths but planthoppers. In this genus there are nine known species, although some are so similar that this number is contentious. One of the three main species of tree that the machaca feeds upon is the west indian locust (hymenaea courbaril), a hardwood tree that can be used for incense.

Strangely, I find records of human fatalities by the juvenile form of the Giant Silkworm Moth (Lonomia obliqua). These caterpillars are covered in venomous hairs that when touched cause a painful bruise-like reaction. This bruising is the effect of their hemotoxin, which causes blood vessels to rupture. When many of these hairy critters are contacted at the same time, such as your arm brushing a group of them on a tree, gangrene-like damage appears around the contacted area. The hemotoxin enters the bloodstream, bursting capillaries and cells as it goes which can be fatal. In fact, more people a year die from these caterpillars than jaguars. They are however primarily found in Brazil, never in Ecuador and do not fit the stories.

Does the machaca have a stinger?

I found a website with the adjacent photo showing a machaca with what appears to be a rear pointing spine on its underside that  deals death. Okay, its not a bite, but that is a flugora and a stinger would get around the issue of tiny mouth-parts. Another initial doubt I had is that there are broadly two types of venom (hemotoxin and neurotoxin), neither of which induce fever like symptoms. What I though the most likely scenario would be is that a parasite associated with the bite (like malaria to the mosquito), but a stinger makes that even less likely. The photo appears to depict a stinger however, so I considered that I might be wrong and kept looking

I wrote to people around Ecuador to see if they knew of the machaca and to my surprise people all over the country said they had. Those entirely out of the Amazon by the coast feared the creature and the same was true even in the high Andes. I widened the inquiry and people from Paraguay to Mexico were also wary of this animal in their own countries. The story varied only slightly, most notably the length of time you were required to have sex in ranging from 12 hours to 72 hours. An insect that lives from scorching equatorial coasts, to snow capped mountains; ranging over a thousand kilometres from the jungles of Mexico to the semi-arid pastures of Paraguay; that could kill a person but was unconfirmed by science. This can only be a conspiracy of the highest level!

The juvenile form of the deadly giant silk moth.

Or conspiracy is what some people jump to when they only look for information that supports their belief rather than also look for information aiming to disprove such.

It transpires that this is all just a story that got a bit out of hand. In 1970, a Colombian journalist by the name of Henry Houguín wrote funny stories called The Chronicles of the Crush, featuring the comical looking machaca. I’m not sure what the “stinger” is but as the myth is confirmed to have been started by a journalist clearly people are biased by their beliefs and being fooled. Seeing is not believing.

This whole debacle demonstrates the cataclysmic danger of knowing something without checking sources, blindly trusting the repute of others. Some people go too far the other way and even seem to distrust “science” as some kind of agent of a corrupt government or organisation. A distrust of vaccines is a good example for despite the quantifiable results people still disavowal the science community as if every single accredited expert is in on a scam, but again, one person, Andrew Wakefield, who accepted bribes to make his claims, is the source of these monstrously harmful lies. Rather than accept that there is mercury in vaccines, for example, investigate why and you’ll learn that it is the harmless ethyl mercury compound.

The methodological processes of science are designed to be the most quantifiable and objective ways of establishing truth. We must continually ask ourselves ‘what if I am wrong’, even with long held beliefs (especially with!) which we have asked ourselves this before. Can you imagine if Nazi supporters, who believed they were purifying humanity for the greater good, asked themselves what if I am wrong. This moth myth may be humorous but there are many “machacas” in Western society too, they’re just less creative and more harmful.


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