The mushroom Entomophthora muscae has a survival strategy that’s both fascinating and likely to deter you from your next meal: it infects and “zombifies” female house flies before sending out irresistible chemical signals encouraging male house flies to become necrophiliacs.
By attracting these male flies to mate with zombified females, the fungus can transfer to the male fly and, in theory, have a better chance of further dispersal. The unlucky male fly is then taken in by E.muscae in the same way.
Crucial to the process is the release of sesquiterpenes, or chemical messages, which are synthesized in the female corpse and sent as a seduction signal. According to the experiments conducted by the researchers, the longer the corpse has been dead, the more attractive it seems to males.
“The chemical signals act like pheromones that bewitch the male flies and cause them to crave an incredible urge to mate with the carcasses of lifeless females,” says evolutionary biologist Henrik H. De Fine Licht of the University of Copenhagen. in Denmark.
Once E.muscae has infected a female fly with its spores, it begins to multiply. After about six days, he can control the behavior of the insect by sending it to the highest possible point (on a wall or a plant) before it dies. Mushroom spores are then sent up by the dead fly, hoping to land on another.
But as this new study shows, by attracting a man, E.muscae can ensure that it passes into at least one other host, which will once again carry its spores away.
The team used a variety of chemical analysis and genetic sequencing techniques to determine exactly what the fungus was doing, as well as exposing the male flies to female partners at different stages of fungal infection, or who had died. other causes.
“Our observations suggest that this is a very deliberate strategy for the fungus,” says H. De Fine Licht. “He’s a true master of manipulation – and it’s incredibly fascinating.”
The tests showed that corpses of female flies dead for 3 to 8 hours attracted 15% of the male flies, while for corpses dead for 25 to 30 hours, this figure reached 73%. The more time passed, the more chemical signals were released.
This isn’t the only time scientists have observed the use of sesquiterpenes to attract the attention of insects. When it comes to chemical signals, he seems to be one of the most effective at manipulating these tiny creatures.
There are many opportunities for further research here, including effective fly repellents – flies can infect humans with various diseases, and sesquiterpenes could be used to lure flies away from certain areas, such as those where food is prepared.
“This is where the Entomophthora muscae Mushrooms can be helpful,” says H. De Fine Licht. “We might be able to use these same fungal scents as a biological pest control that attracts healthy males to a fly trap instead of a corpse.
The research was published in the ISME Journal.