The psilocybin in magic mushrooms is an insect repellant

The psilocybin in magic mushrooms is a potent psychedelic for animals. But what good is the psilocybin for the shrooms? New genetic research from Ohio State University suggests that the psilocybin might act as an insect repellant, protecting the mushrooms. From New Scientist:

The gene cluster (linked to psilocybin production) is found in several distantly related groups, suggesting that the fungi swapped genes in a process called horizontal gene transfer. This is uncommon in mushrooms: it is the first time genes for a compound that is not necessary for the fungi's survival - called a secondary metabolite - have been found moving between mushroom lineages.

Since these genes have survived in multiple species, Slot thinks psilocybin must be useful to the fungi. "Strong selection could be the reason this gene cluster was able to overcome the barriers to horizontal gene transfer," (researcher Jason Slot) says.

Hallucinogenic mushrooms often inhabit areas rich in fungi-eating insects, so Slot suggests psilocybin might protect the fungi, or repel insects from a shared food source, by somehow influencing their behaviour.