SPRINGFIELD -- Illinois officials are asking residents to help increase Monarch butterfly populations by planting and preserving milkweed.
Scientists have noted the official state insect has been dwindling in numbers on its wintering grounds in Mexico since the 1990s.
Monarch butterflies lay their eggs on the 19 species of milkweed in Illinois.
The larva that hatches feeds on the plant for about two weeks until forming a chrysalis and becoming a butterfly.
The Department of Natural Resources encourages residents to plant milkweed and native flowering plants and avoid mowing or spraying herbicide on milkweed patches.
Milkweed grows readily along roads, fields and other untended places. Officials say reducing mowing saves fuel and provides habitat.