Danish researchers have identified a fungus capable of transforming flies into zombies and then into real sex Trojans.
Our environment is full of breathtaking phenomena, which sometimes flirt with magic. But when you look behind this magical storefront, Mother Nature can also turn out to be quite abominable. This is the conclusion that emerges from reading this work by Danish researchers identified by ScienceAlert; they have indeed documented the case of a funny fungus, which turns flies into real zombie Trojans.
There is indeed something to frown on, but it is nevertheless a study that could not be more serious on a parasite called Entomophthora muscae. To ensure its offspring, this fungus has developed a convoluted and nightmarish ploy that begins with simple flies.
Like all living beings, evolution has imposed on them a non-negotiable vocation: to reproduce, at all costs. But if they make it possible to ensure the survival of the species, these impulses are also a mechanism that can be exploited. And that’s where comes in Entomophthora muscae. When our fungus places its spores on a female fly, it will gradually colonize its entire organism. Eventually it reaches the hemolymph, the equivalent of blood in insects, and this is where a real animal horror film.
A Hollywood Zombie Story
Now well established in its victim, the fungus will continue to grow until it reaches the central nervous system. Once this is reached, the ramifications will penetrate to the brain of the fly… and thus completely alter its behavior. The victim is now a real zombie, whose natural instincts were partially reprogrammed by the parasite. But this is only the beginning of the process. Once in control, the fungus gradually digests the entire fly from the inside. Once it is in critical condition, the contamination of the nervous system causes the victim to crawl to a small perch high up, where it will eventually die after a few days.
At this stage, the fly is clinically dead; but the mushroom, satisfied with his new home, is far from having finished with his fatal puppet. It continues to grow until the corpse is completely overflowing with conidia, which are real little spore factories. And since the fly has took the trouble to die high up, the latter are ejected at the first gust of wind, giving birth to a new generation of fungi.
In nature, there is no such thing as waste; Entomophthora muscae continues to form conidia until all organic matter in the fly is depleted. If other flies are nearby while ejecting, these may be infected with the fungus. And with a little luck he may even hit the jackpot if a male fly passes nearby.
A formidable Trojan horse
Because if the beginning of the process was not yet raised enough for your taste, the Danish researchers noticed that the mushroom still had one last string to its bow. And this is probably the most disturbing of all. Once mature, it no longer just produces zombifying spores. He also concocts a powerful aphrodisiac for flies. If a male passes nearby, he is seized with irresistible impulses. So irresistible, in fact, that the poor fellow can’t even tell a living animal from a dead animal.
Result: subjugated by this morbid love potion, the male rushes on the first potential partner, who often happens to be a horse – or rather a Trojan fly infected with Entomophthora muscae, strategically placed prominently. And as with humans, decisions made under the influence of an impulse are often ill-advised. As soon as the poor male comes into contact with the zombie, he is exposed to the spores of the fungus, with the disastrous consequences that we all know.
It is very far from being the first species to exploit the reproduction of other animals; for example, many plants are known which use this stratagem to increase their chances of being pollinated. But according to the researchers, this is one of the very first times that a fungus has shown itself capable of such broad behavioral manipulations, which affect even uninfected organisms.
At the end of the day, this isn’t just an entomological horror movie. According to the researchers, these findings could help to learn more about the molecular signals to which flies respond. Ultimately, this could make it possible to develop repellents very useful in public health. They could be used in particular in regions where these flies are vectors of human diseases.
The text of the study is available here.