Answer:
They would freeze and it would be hard to find food because they are not accustomed to the different climate. They would also be easy prey because of the environment change they are not equipped for.
So the dark butterfly camouflages better on the tree. Where as the white one can clearly be seen and identified. A predator will also easily spot it and kill it. The dark butterfly has evolved over time to the color that it is, to best help it survive. This is also shown in the tread on the graph.
Hope this helps!!
