However, body coloration is usually obscured by a black globule of mucus and fecal matter held on the body, giving the larva shiny black, wet appearance. This liquid substance wipes off easily and after walking in an infested field, a person's shoes and trouser legs will be soiled. In the spring, adults colonize and lay eggs in small grain fields during March and April, although it can be earlier or later depending on spring temperatures. Eggs hatch in about five days. Larvae develop in about 10-12 days under ideal temperatures, however, development times vary considerably during the spring.
Small larvae eat a very small amount but when full grown, larvae have a voracious appetite.
Upon reaching full size, the larvae dig into the ground and pupate. After a short period in the soil a new summer generation of adult beetles emerges in late-May and June. New beetles move from small grain fields and feed on grass plants for a short period but then remain inactive through most of the summer. Since these adults need to feed before becoming inactive they often congregate and feed in corn fields adjacent to the small grains from which they emerged. Adult feeding on corn appears like many line-etchings on the blades and can cause concern to the farmer.