Do Japanese Beetles Hibernate?

Japanese beetles do not hibernate through the winter. It may seem like they do because they are only around for a short few months out of the year before disappearing.

The reason for that is because their adult stage  is very short and lasts only 1 to 3 months. They live only long enough to reproduce and thus ensure that next year’s group of Japanese beetles will arrive.

During the rest of the year, Japanese beetles are buried underground. Japanese beetle eggs are deposited underneath the surface of the earth and when the eggs hatch and become grubs, they remain there for about nine months while they develop.

I suppose this could be considered a form of hibernation, with the grubs buried underground and mostly inactive. But technically, it is not hibernation. They are just hidden from sight but are not completely inactive.

The grubs are constantly feeding, mostly on plant roots, and growing in size as the months go by. When late May arrives, they will hatch into adults and rise to the surface to eat the leaves of plants and trees.