What’s the Life Cycle of the Japanese Beetle?

The full life cycle of the Japanese beetle is short, lasting only about a year under normal conditions. In cooler cold temperatures, however, Japanese beetles can live up to two years.

Adult female Japanese beetles mate in the early summer months and prefer to lay their eggs in grassy locations with lots of moisture. The grass provides cover for the eggs and subsequent larva and also supplies them with an easy food source nearby.

After a few weeks, the Japanese beetle larva emerge from the eggs and begin feeding on any plant material nearby (they are not picky). They are not ready to become adults yet, and soon enter their hibernation period, called the pupa stage.

The pupa stage is the longest part of the Japanese beetles life cycle and can last many months and sometimes even years. During this stage, the growing beetle is in a sort of state of suspended animation.

The pupa is waiting for environmental conditions to dictate when it is most advantageous for it to emerge from its cocoon as an adult. This usually happens during the early summer months when temperatures are warmest and most conducive to mating.

You may enjoy watching this short video regarding the life cycle of the Japanese beetle: