Yes, they have to have a victor. Without a victor, the whole thing would blow up in the Gamemakers' faces. They'd have failed the Capitol. Might possibly even be executed, slowly and painfully, while the cameras broadcast it to every screen in the country.
Seen under the microscope, Stegomyia is a creature of striking beauty. Its general color is dark gray, but the thorax is marked with a silvery-white lyre-shaped pattern; the abdomen is banded with silvery-white stripes and the six-jointed legs are striped alternately with black and pure white. Among mosquitoes Stegomyia is the height of elegance.