They have been noted as a pest for well over 100 years. Over the years this beetle species has been know by several scientific names. Life History Cottonwood leaf beetles overwinter as adults and emerge in the spring to mate and lay eggs. Eggs are usually laid in groups of 20 to 50 often on the undersides of leaves. The eggs are yellow in color and sometimes turn a salmon color before they hatch.
Eggs are visible in the female's abdomen.
Click on pictures to see larger versions and more information. Larvae hatch from the eggs and start eating. There are three larval instars or stages. They are 1 mm or less in length when they hatch but proceed to grow as they eat. Second instar larvae are a slightly lighter color and are bigger.