O. unilateralis’ life cycle includes and depends on the infection and the manipulation of a carpenter ant, principally C. leonardi.
The behavioral manipulation of the ant, which gives rise to the name “zombie-ant”, is an extended phenotype of the fungus.
It first affects the ant’s behavior through convulsions that make it fall from its high canopy nest onto the forest floor.
This is followed by the fungus controlling the climbing of the ant and the locking of its jaw (and subsequent death) onto a leaf around 25 centimetres above the ground, which is thought to be the optimal height for fungal spore growth and dispersion.

Throughout the lifecycle, unique challenges must be met by equally unique metabolic activities.
The fungal pathogen must attach securely to the arthropod exoskeleton and penetrate it—avoiding or suppressing host defenses—then, control the behavior of the host before killing it; and finally, it must protect the carcass from microbial and scavenger attack.

The behavioral manipulation of the ant would not be possible without the presence of huge fungal cell populations beside the host’s brain and within muscles because these lead to the secretion of various metabolites known to have important behavioral consequences.
During the infection the parasite comes across an array of environments such as different host tissues or the immune response.
Studies have shown that O. unilateralis reacts heterogeneously by secreting different metabolites according to the host tissue it encounters and whether they are live or dead.
The identification of these natural products is important in order to understand which aspects of the ants are under control and consequently how O. unilateralis manipulates the ant.

Attachment O. unilateralis spores onto the ant’s exoskeleton
The first step O. unilateralis has to overcome to have a successful infection, is to attach itself onto the ant’s cuticle and then infiltrate it.
For this purpose, the fungus’ hypha pierces the exoskeleton using enzymes such as chitinase, lipase and protease, combined with mechanical pressure.

Convulsions and climbing behaviour
After the fungus enters the ant it propagates, and fungal cells are found beside the host’s brain.
Once the population is of sufficient size, the fungus secretes compounds and takes over the central nervous system (CNS), which enables it to manipulate the ant to reach the forest floor and climb up the vegetation.

Two candidate compounds, sphingosine and guanidinobutyric acid (GBA), were identified as responsible for the manipulation of the host brain.
Both of these metabolites are known in the scientific world to be involved in neurological disorders.
However, more research is needed in the field to determine whether other fungal metabolites interact with the host brain and cause higher levels of sphingosine and GBA in the brain.

Some studies identified another compound, hypoxanthine, present at high extracellular concentration.
Hypoxanthine has deleterious effects on neural tissues of the cerebral cortex, which in the context of zombie ants may indicate a way for the fungus to alter the motor neurons of the ant, consequently affecting its behavior.

Death grip
The famous “death grip” exhibited by the ant is also a result of the fungus-induced manipulation.
The behavior consists in the ant biting the leaf so tightly that the ant is prevented from falling as it dies hanging upside down, consequently enabling the proper growth of the fungus’ fruiting body.

This is possibly a result of the atrophication of the ant’s mandibular muscles caused by the secretion of fungal compounds.
In multiple studies, fungal cell populations were found within atrophied mandibular muscle tissues.
In fact, they infiltrate between the muscle fibers and it is a common hypothesis of researchers that they cause the muscles’ atrophication the secretion of chemicals.

Significant decreases in leucine concentration and mitochondria number were identified in infected ants.
A deficit in leucine results in the prevention of muscle regeneration because the amino acid is
O. unilateralis’ life cycle includes and depends on the infection and the manipulation of a carpenter ant, principally C. leonardi. The behavioral manipulation of the ant, which gives rise to the name “zombie-ant”, is an extended phenotype of the fungus. It first affects the ant’s behavior through convulsions that make it fall from its high canopy nest onto the forest floor. This is followed by the fungus controlling the climbing of the ant and the locking of its jaw (and subsequent death) onto a leaf around 25 centimetres above the ground, which is thought to be the optimal height for fungal spore growth and dispersion.
Throughout the lifecycle, unique challenges must be met by equally unique metabolic activities. The fungal pathogen must attach securely to the arthropod exoskeleton and penetrate it—avoiding or suppressing host defenses—then, control the behavior of the host before killing it; and finally, it must protect the carcass from microbial and scavenger attack.
The behavioral manipulation of the ant would not be possible without the presence of huge fungal cell populations beside the host’s brain and within muscles because these lead to the secretion of various metabolites known to have important behavioral consequences. During the infection the parasite comes across an array of environments such as different host tissues or the immune response. Studies have shown that O. unilateralis reacts heterogeneously by secreting different metabolites according to the host tissue it encounters and whether they are live or dead. The identification of these natural products is important in order to understand which aspects of the ants are under control and consequently how O. unilateralis manipulates the ant.
Attachment O. unilateralis spores onto the ant’s exoskeleton
The first step O. unilateralis has to overcome to have a successful infection, is to attach itself onto the ant’s cuticle and then infiltrate it. For this purpose, the fungus’ hypha pierces the exoskeleton using enzymes such as chitinase, lipase and protease, combined with mechanical pressure.
Convulsions and climbing behaviour
After the fungus enters the ant it propagates, and fungal cells are found beside the host’s brain. Once the population is of sufficient size, the fungus secretes compounds and takes over the central nervous system (CNS), which enables it to manipulate the ant to reach the forest floor and climb up the vegetation.
Two candidate compounds, sphingosine and guanidinobutyric acid (GBA), were identified as responsible for the manipulation of the host brain. Both of these metabolites are known in the scientific world to be involved in neurological disorders. However, more research is needed in the field to determine whether other fungal metabolites interact with the host brain and cause higher levels of sphingosine and GBA in the brain.
Some studies identified another compound, hypoxanthine, present at high extracellular concentration. Hypoxanthine has deleterious effects on neural tissues of the cerebral cortex, which in the context of zombie ants may indicate a way for the fungus to alter the motor neurons of the ant, consequently affecting its behavior.
Death grip
The famous “death grip” exhibited by the ant is also a result of the fungus-induced manipulation. The behavior consists in the ant biting the leaf so tightly that the ant is prevented from falling as it dies hanging upside down, consequently enabling the proper growth of the fungus’ fruiting body.
This is possibly a result of the atrophication of the ant’s mandibular muscles caused by the secretion of fungal compounds. In multiple studies, fungal cell populations were found within atrophied mandibular muscle tissues. In fact, they infiltrate between the muscle fibers and it is a common hypothesis of researchers that they cause the muscles’ atrophication the secretion of chemicals.
Significant decreases in leucine concentration and mitochondria number were identified in infected ants. A deficit in leucine results in the prevention of muscle regeneration because the amino acid is 
Ophiocordyceps unilateralis