The Zombie Ant: Parasitic Fungi and Behavior Manipulation
Biology 342 Fall 2014
While the exact mechanisms behind this phenomenon are largely unknown, preliminary studies have investigated the biochemical causes of the behavioral manipulation of ants.
The metabolic substances GBA and sphingosine. which have previously been linked to neurological disorders, are possibly involved in the fungi's ability to manipulate host ants.
While some research has been done into the mechanisms and compounds underlying the parasitic manipulation of ant behavior, much remains to be explored and understood in the area. By examining the metabolites that the fungus secretes in reaction to the brains of varying ant species, researchers have discovered candidate compounds that O. unilateralis employs for brain manipulation. While O. unilateralis successfully kills all the ant species tested, it was determined that the fungus is only able to manipulate the behavior of the species that it naturally infects. Two candidate metabolites isolated were guanobutyric acid (GBA) and sphingosine, both of which are allegedly involved in some neurological disorders. These two compounds developed in greater levels when O. unilateralis infected its target species. However, further research must be performed to verify these findings (Bekker et al., 2014).
Compounds secreted by parasitic fungi facilitate insect infection by suppressing the host's immune system.
In other parasitic fungal species that target insects, researchers have found that the fungi secrete immunosuppressive toxins. These toxins can damage cytoskeletal structures, induce apoptosis, and interfere with the host immune system, thereby mediating the fungiís virulence (Vilcinskas and Gotz, 1999). It is possible that O. unilateralis operates via a similar mechanism.