Answer:
Favorable adaptation, which is one condition required for natural selection
Step-by-step explanation:
A population have both beneficial and harmful variations present in its members. The beneficial variations impart survival advantage and makes the individuals better adapted to the surrounding. Several butterflies in the given population have dotted wings. Since presence of dotted wings keeps the predators away, it is a favorable variation that would be favored by natural selection leading to its increase in the population in subsequent generations.