When the wasp larva hatches form the egg it begins eating the blood and fat of corn-ear worm. In a short period of time, the corn-ear worm dies. The wasp lays only one egg in the worm. If another worm attacks the plant, It will release another chemical signal. The wasp may return to the plant if it smells the chemical. But, having marked the first worm with its own special smell, the wasp will pass it by and look for the second worm.