https://www.scientificamerican.com/article/how-do-periodical-cicadas-know-when-to-emerge/ https://www.scientificamerican.com/article/how-do-periodical... Some

https://www.scientificamerican.com/article/how-do-periodical-cicadas-know-when-to-emerge/ https://www.scientificamerican.com/article/how-do-periodical... Some how they keep track of the growing cycle of the trees they feed on.