Polydrusus sericeus

Green Immigrant Leaf Weevil

Polydrusus sericeus, Green Immigrant Leaf Beetle

Family: Curculionidae

Subfamily: Entiminae

Length: 5.0 - 6.5 mm


The usual food plant for the Green Immigrant Leaf Weevil is Betula alleghaniensis, Yellow Birch.

In mating pairs of Polydrusus sericeus the females are almost invariably larger than the males. It is not uncommon for females lay more than 1,000 eggs over their lifetime; one female produced 1,342 eggs (Hillstrom et al, 2010).

Hillstrom and his coauthors studied the effects of elevated carbon dioxide and ozone on Polydrusus sericeus in Wisconsin. They concluded that at current levels there is little effect on the weevils' longevity, number of eggs laid, amount of leaves consumed, etc. On the other hand, the carbon dioxide and ozone levels projected for the year 2100 may result in reduced female fecundity and reduced female longevity (Hillstrom et al, 2010).

This species is found in Ontario, Quebec, and New Brunswick, and over much of the northeastern United States.

Photo location: Lake County, Minnesota.

American Insects site