Zombie Fungus Enslaves Only the Brain of Its Favorite Ant
As Halloween nears, we felt like switching it up a bit and posting somewhat of a spooky blog post vs. the standard normal. So in this topic, we will discuss zombies! however, unlike the other zombies that take over the mind of every host they feed on, research has shown that a parasitic zombie fungus which only injects its mind-controlling chemical concoction into the brain of its preferred ant species. We dodged the bullet, and luckily so, as it does not affect humans! Actually, the fungus cordyceps is thought to have some health properties and is sold as a performance-enhancing supplement!
According to Charissa de Bekker of the Department of Molecular Biology at Pennsylvania State University, who led the research study published in the journal BMC Evolutionary Biology, this complex of behavioral manipulation is based on every specie of ant is evolutionarily related to a specie of fungus. Hence, the phenomenon only occurs the fungus attacks their ant counterpart.
The Zombie ant fungi- scientifically called Ophiocordyceps – need to infect ants before they can complete their life cycle. The fungal spores lie waiting for an ant to come in contact with them. Immediately they do, the fungus spreads its spores around the ant, thereby infecting it.
It releases its mind-controlling cocktail into the brain of the insect and takes over its central nervous system. While no longer in control of its mind, the ant crawls up vegetation, and then a stalk grows out of its head and extends to the ground below to infect other insects.
The researchers found that different species of Ophiocordycep only affect certain plants. They speculated that this could be because of specific differences in ants' lifecycles, or maybe the unaffected ants haven't yet been in contact with the spores.
To clarify this speculation, the researchers used Ophiocordyceps unilateralis sensu lato- a fungal species discovered by Kim Fleming in 2009 and known to make two carpenter ant zombies species, Camponotus americanus and Camponotus castaneus.
They injected the two carpenter ants with fungal materials. They also injected the same materials into Formica dolosa and Camponotus pennsylvanicus, two of which do not serve as host to any known fungus species. Two control groups of ants were also sampled. One group was injected with fungus-free liquid, while the other was left without any injection.
The three Camponotus species died during the experiment, while only the two known hosts exhibited the mind-control trick. F. dolosa, however, died shortly after the injection.
Understanding mind-controlling chemicals
Intrigued by the findings so far, the researchers checked if the fungus secretes a particular sequence of chemicals that effectively manipulate C. americanus and C. castaneus.
According to de Bekker, they sampled the same four ant species they used for the injection studies. They dissected their brains and cultured them in a cell culture medium to keep the brains alive. Next, they introduced fungus into the medium and extracted the medium after the fungus had reacted to the environment and released its molecules.
The researchers found thousands of unique known and unknown chemicals. After separating the substances produced from the insect brain and those produced by the fungus in response to the medium, they isolated lots of chemicals secreted by the fungus in response to the ant brains.
Further analysis showed that the fungus produced a unique cocktail for each species of ants for each ant species. Unlike the target hosts that reacted as expected, De Bekker noted that the fungus didn't produce the right cocktail to manipulate C. pennsylvanicus or F. dolosa because they didn't coevolve with these insects.
Further studies showed that the cocktail contains sphingosines and guanidinobutyric acid (GBA), which are both responsible