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Insects and other arthropods

Japanese beetle

Popillia japonica

Tabs group


These beetles are recognizable by their bright metallic colours. The head and thorax are usually green, and the elytra (wing covers) are copper. There are five small tufts of white hair on either side of the abdomen. They reach 12 mm long.

The white grubs have brown heads and three sets of legs. They adopt a crescent-shaped position in the soil, and may be up to 32 mm long.

Life cycle

These insects complete their life cycle in one year. The adults emerge in June and July. After mating, the females lay from one to five spherical eggs in moist soil. They can mate several times and produce from 40 to 60 eggs over the summer.

The larvae hatch two weeks later. They feed on plant roots until temperatures drop in the fall. At that point they burrow deeper into the soil, to depths of 10 to 20 cm, to escape the cold. They make their way back toward the surface in the spring and begin feeding again. When they reach maturity, they stop eating and pupate before turning into adults.

Geographic distribution

The species originated in East Asia and was accidentally introduced into the United States, where it was spotted for the first time in 1916 in New Jersey.

It is now found in the west as far as Missouri, with some populations in California. In Canada, it occurs from Ontario to Nova Scotia. 

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