A creepy species of parasitic fungus turns flies into 'zombie' necrophiles by emitting a powerful chemical aphrodisiac, a new study shows.
Researchers in Denmark have found the fungus species, Entomophthora muscae, releases a potent mix of fungal compounds once it's fatally infected a female housefly.
Healthy male houseflies respond to the intriguing mix of chemical compounds by mating with the dead zombie female, ensuring the fungus' spread.
After E. muscae infects houseflies, it penetrates their skin, grows spores throughout their body, digests their guts and kills them in five to seven days.
A fly killed by the killed by Entomophthora muscae fungus, which ascend to a high point and spread their wings to spew spores from their abdomen
The new study has been led by researchers at the University of Copenhagen, who gave male flies the option to mate with infected and non-infected dead females.
'Healthy males are attracted to fungus-killed cadavers [dead bodies] and engage in courtship and mating attempts, which significantly increase infection of new host individuals and thereby ensures transmission of the fungal pathogen,' the authors say.
'Infection with E. muscae induces changes in the volatile chemistry that attract house flies by both altering the levels of cuticular fly hydrocarbons and by producing several unusual volatile compounds.'
The 'unusual volatile compounds' include a class of chemicals called sesquiterpenes, not previously associated with house flies.
Sesquiterpenes have already been found to be attractive in several other insects, the researchers report, including the Asian honey bee and bumblebees.
Previous studies have already detailed E. muscae's ruthless process of infection. Its genus name, Entomophthora translates to 'destroyer of insects' – and it's no surprise why.
Once infected, spores called conidia are produced from the fly – a process called sporulation.
E. muscae causes flies to ascend to a high point and spread their wings like a marionette on a string, to eventually spew the spores from their swollen abdomen.
The fungus invades the fruit fly's nervous system and forces it to embark on the fatal climb, known as 'summit disease', before devouring the brain and muscles.
Entomophthora muscae turns its victim into a zombie. Once infected, E. muscae causes flies to ascend to a high point and spread their wings like a marionette on a string, to spew spores from their swollen abdomen
When the fly is dead, the fungi grows an array of micro-sized stalks on the corpse, each one a pressurised cannon of liquid with a spore that can be ejected outwards.
Unfortunate male flies are attracted to 'zombie' female fly corpses – and when they accidentally trigger the cannons, they end up coated in a spray of infectious spores.
This ensures that the fungal spores are dispersed as widely as possible so the gruesome process happens again on another fly.
Now, the researchers show that it's not only the altered size and appearance of the dead fly that attracts unsuspecting males, but the potent compounds, which act as something of a love potion.
