Zombie Fungus:
Main Story:
A
stalk of the newfound fungus species Ophiocordyceps camponoti-balzani, grows
out of a “zombie” ant’s head in a Brazilian rain forest. Originally thought to
be a single species, called Ophiocordyceps unilateralis, the fungus is actually
four distinct species—all of which can “mind control” ants.
The fungus species infects an ant, then takes over its brain
(what is it about Zombies and brains) and then kills the insect once it has
moved to a location that is ideal for the fungi to grow and spread their
spores.
|
Ophiocordyceps Unilateralis |
Explanation:
According to some scientists;
"It is tempting to
speculate that each species of fungus has its own ant species that it is best
adapted to attack," Hughes said.
"This potentially
means thousands of zombie fungi in tropical forests across the globe await
discovery," he said. "We need to ramp up sampling—especially given
the perilous state of the environment.” Matt
Kaplan said.
Identification of infected ant:
The infected ant can be identified at the end of his life cycle by its reproductive system by a wiry yet pliant darkly pigmented stoma stalk extending from the back of the deceased ant's head.
How does the fungus attack's an ant???:
The
fungus's spores enter the body of the insect likely through the cuticle by
enzymatic activity, where they begin to consume the non-vital soft tissues.
Yeast stages of the fungus spread in the ant's body and presumably produce
compounds that affect the ant's brain and change its behavior by unknown
mechanisms, causing the insect to climb up the stem of a plant and use its mandibles to secure itself to the plant. Infected ants
bite the leaf veins with abnormal force, leaving telltale dumbbell-shaped
marks. A search through plant fossil databases revealed similar marks on a fossil
leaf from the "Messel pit" which is 48 millions old.
The fungus then kills the ant, and continues to grow as its
mycelia invade more soft tissues and structurally fortify the ant’s
exoskeleton. More mycelia then sprout out of the ants, and securely anchor it
to the plant substrate while secreting antimicrobials to ward off competition. When
releasing the spores. This process takes four to ten days.
The changes in the behavior of the infected ants are very
specific, giving rise to the term “Zombie ants”, and tuned for the benefit of
the fungus. The ants generally clamp to a leaf’s vein about twenty five cm
above the ground, on the northern side if the plant, in an environment with
94-95% humidity and temperatures between 20 and 30°C. when the dead ants are
repositioned in various other situations, further vegetative growth and
sporulation either fails to occur or results in undersized and abnormal
reproductive structures.
However the ants have developed sense to identify the
infected ants, they recognize the infection and then carry the infected “Zombie
Ant” away from their nest to prevent others ants from the fungus infection.
But is there only one species of fungus? Harry Evans, Simon Elliot and David Hughes were inrigued by the original description of Torrubia unilateralis, as it was called at the time. In 1865, Louis Rene Tulasne a French mycologist, described a leaf-cutting and as the host for the fungus. His brother, Charles Tulasne, worked with him and illustrated their findings. Charles’s drawing of an infected ant does not depict the leaf-cutter: rather, it appears to be a carpenter ant, with its characteristic spines. The fungus has only ever been found infecting carpenter ants. Could Louis have made a mistake? Maybe there other species of ant-zombifying fungi out there?