A fly-zombie fungus ‘enchants’ healthy males to mate with the corpse of a female infected with the fungus to ensure her survival – and the longer the insect is dead, the more attractive it becomes, scientists have found
- The study found that 73 percent of male flies that mated with female carcasses died from a fungal infection 25 to 30 hours ago.
- Only 15 percent of males mate with the corpses of females that have been dead for three hours.
- The fungus releases a chemical signature that acts like a pheromone to lure unsuspecting males.
A fungus that turns houseflies into zombies ensures their survival by “enchanting” males to mate with fungus-infected corpses of dead females. A new study has found that the longer a female is dead, the more attractive she is to a male.
The fungus, officially known as entomophora muscae, infects the female fly, slowly eating it from the inside, and then about a week later, the spores take on the behavior of the already dead insect.
And once it has full control, the fungus releases a chemical signature that acts like pheromones to lure unsuspecting males.
When a male copulates with the corpse of an infected female, the fungal spores attach to the male, which in turn also becomes a zombie housefly.
Scientists from the University of Copenhagen found that 73 percent of the male flies copulated with the carcasses of females that died from a fungal infection 25 to 30 hours ago.
Only 15 percent of the males mated with the corpses of females that had been dead for three hours.
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The fungus that turns houseflies into zombies ensures its survival by “enchanting” males to mate with the fungus-infested corpses of dead females – and a new study shows that the longer a female is dead, the more attractive she is to a male.
Henrik H. De Fine Licht, assistant professor of environmental and plant sciences at the University of Copenhagen and one of the authors of the study, said in statement: “We see that the longer the female fly is dead, the more attractive it becomes to males.
“This is because fungal spores increase over time, which enhances enticing scents.”
The team believes this discovery could also lead to the development of a more effective fly killer.
Licht adds: “Flies are quite unhygienic and can cause disease in humans and animals by spreading E. coli bacteria and any diseases they carry.
Entomophthora muscae turns its victim into a zombie. Once infected, E. muscae causes the flies to rise to a high point and spread their wings like marionettes on a string to regurgitate spores from their bloated belly.
Thus, there is an incentive to limit housefly populations, for example, in areas where food is produced.
A fungus that turns houseflies into zombies
Entomophthora muscae infects houseflies by penetrating their skin.
It grows all over the body of the flies, digesting their intestines and killing them in five to seven days.
Fungi can even take over the brains of insects, causing them to land on surfaces and crawl upwards to give the parasite the best chance to spread.
On the fly’s corpse, the fungi grow many tiny spore cannons to infect other flies that come close.
“This is where the fungus Entomophthora muscae can be useful. We may be able to use the same mushroom scents as a biological pest control that attracts healthy males to the fly trap instead of the carcass.”
Previous studies have already detailed the relentless infection process of E. muscae. The genus name Entomophthora translates as “insect destroyer” – and it’s no wonder why.
Once infected, the fly produces spores called conidia, a process called sporulation.
E. muscae causes flies to rise to a high point and spread their wings like puppets on a string to eventually regurgitate spores from their bloated belly.
The fungus enters the fruit fly’s nervous system and forces it into a lethal climb known as “apex disease” before engulfing the brain and muscles.
When the fly is dead, the fungi will sprout many micro-sized stems on the corpse, each of which is a pressurized fluid cannon with a spore that can be ejected.
The unfortunate male flies are attracted to the corpses of the female zombie flies, and when they accidentally set off the cannons, they end up covered in a spray of infectious spores.
This ensures that the fungal spores are dispersed as widely as possible so that the terrible process can be repeated on another fly.
In general, the process of infection with E. muscae in male and female houseflies does not differ.
Licht is one of the scientists who first discovered how a fungus turns flies into “necrophilic zombies” by releasing a chemical signature.