Scientists built a zombie fungus cannon to show how spores are spread to a new host
- Entomophthora muscae digest flies inside out and even take over their brains
- They then grow cannons on their hosts’ corpse in order to spread their spores
- The exact mechanism that allows these cannons to fire had been unclear
- Experts used a home-made cannon to show how efficient the fungal guns are
Scientists have built a ‘zombie fungus cannon’ to find out exactly how a bizarre fungus spreads by turning the corpses of dead flies into infectious launch pads.
Entomophthora muscae infects houseflies, penetrating their skin, growing throughout their body, digesting their guts and killing them in five–seven days.
Along the way, the fungi can even hijack the insects’ brains — forcing them to land on a surface and crawl upwards to give the parasite a better shot at spreading itself.
When the fly is dead, the fungi grows on the corpse an array of micro-sized stalks, 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.
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Scientists have built a ‘zombie fungus cannon’ to find out exactly how a bizarre fungus spreads by turning the corpses of dead flies into infectious launch pads
HOW DOES E. MUSCAE USE HOUSEFLIES?
Entomophthora muscae infect houseflies, penetrating their skin.
It grows throughout the flies’ bodies, digesting their guts and killing them in five–seven days.
The fungi can even hijack the insects’ brains — forcing them to land on a surface and crawl upwards to give the parasite a better shot at spreading.
On the fly corpse, the fungi grows an array of tiny spore cannons to infect other flies that come nearby.
To investigate exactly how these fungal cannons work, physicist Jolet de Ruiter of the Technical University of Denmark and colleagues created a similar weapon of their own in their laboratory.
The researchers cannon comprised a millimetre-sized barrel made of a rubber-like polymer, filled with fluid and plugged at the end with a projectile.
By carefully controlling the pressure in the cannon as it built up to ejection, the tea, were able to study the efficiency of the dispersal weapon.
They measured this in relation to the barrel’s size and shape, as well as the elasticity of the cannon’s sides.
From this, the researchers were able to show that the real-life fungal spore cannons are well-configured to traverse the still air around a fly corpse.
From here they reach the air currents created by its target and can go on to infect a new host.
‘The calculated flight trajectories under aerodynamic drag predict that the minimum spore size required to traverse a quiescent layer of a few millimetres around the fly cadaver is approximately 10 micrometers,’ the researchers wrote in their paper.
‘This corroborates with the natural size [of] E. muscae [spores] — approximately 27 micrometers — being large enough to traverse the boundary layer.’
To investigate exactly how these fungal cannons work (left), researchers led from the Technical University of Denmark created a similar weapon of their own in their lab (right)
The spores, they added, are still ‘small enough — less than 40 micrometers — to be lifted by air currents,’ the researchers continued.
‘Based on this understanding, we show how the fungal spores are able to reach a new host.’
The full findings of the study were published in the Journal of the Royal Society Interface.