After seeing the modus operandi of the fungus of The Last of Us; that, to top it off, exists in real life, we are not surprised that there are fungi capable of manipulate living beings. But they don’t always act alone. Sometimes they team up with other living beings, becoming a double jeopardy for their victims. It is the case of the fungus Grosmannia penicillata and the Eurasian spruce bark beetle (Ips typographus).
And it is that, as explained in a study recently published by scientists from the Lund University and the Max Planck Institute, in Sweden, both need the fir trees and collaborate to share the prize in a curious symbiotic relationship. The fungus thrives by breaking down substances such as the resin generated by the tree. The beetle also feeds and also uses the crevices in the trunk to reproduce.
For years, it has been seen that the two organisms needed the fir trees. Now, however, it is known that some of the substances that the fungus breaks down are those that the tree naturally generates as beetle defense. He is totally sold to the enemy. But, as if that were not enough, it is also marked so that it can be found more quickly. the fungus of The Last of Us works alone. At least for now. This one has collaborators, although, in reality, helping others is a kind of collateral damage.
of the fungus of The Last of Us to F. penicillata
Cordycepsthe genus to which the fungus belongs The Last of Us, exists in real life. Although does not infect humansbut to certain insects, such as ants. Basically, it uses them at will so that they disseminate their spores and participate in their reproduction.
Instead, G. penicillata does not attack animals, but to the plants. More specifically, he is crazy about the organic matter of some species of firs. On the other hand, the beetle I. typographus you also need these plants to feed and reproduce.
In previous studies, scientists have seen that it is more common for beetles to come to fir trees previously infected by the fungus. Not only do they not seem to care, but they like. There was a coincidence. The causality was missing. And now it seems to be much clearer.
Pheromones to attract the beetle
When the fungus infects fir trees, it begins to break down and metabolize many compounds present in its resin. The result is new compounds that the authors of this recent study have observed act as pheromones for beetles. In fact, it is mainly the females, who will finally lay their eggs there, that are seen more attracted.
However, beetles have also been observed to have trouble attacking other firs that are not infected by the fungus. This is because they contain substances capable of even killing any insect that tries to take advantage of them. But those compounds that act as a shield are what the fungus breaks down. It literally leaves the trees unarmed in front of the beetle. Everything that comes after is logical.
Given this, the study authors wanted to check something else. And this is not the only fungus capable of infect and decompose the organic matter of fir trees. There are more, but some can be dangerous to the beetles themselves. If we think about what inspires the fungus of The Last of Us we will understand why.
So these scientists tried exposing the beetles to fir trees infected by both G. penicillata as for another fungus that also disarm the plants. They always chose the first. That is, the one that makes their lives easier, but also does not cause them any harm. Deep down, they know very well what they are doing, even if it is unconsciously.