A Senate Democrat is proposing a special Illinois license plate to help preserve the monarch butterfly. The plan by state Sen. Melinda Bush of Grayslake is to allow motorists to pay a surcharge for stickers to indicate their support for the insect's viability. The monarch population in Illinois has decreased 90 percent in the past two decades because of changes in habitat. Bush says monarchs need milkweed plants to lay eggs and feed. Interstate highway medians could be developed with the plant so the butterfly could visit the milkweeds with little outside distraction. The plate would be the first to comply with a new specialty plate law that provides stickers to put on otherwise standardized plates for easy tracking by law enforcement.