Lady bugs can come in many different colors and some give better natural advantages over others through natural selection.
The first step of natural selection is overproduction of offspring which creates genetic equilibrium in an environment.
When an environment changes the gene pool of a species can change through natural evolution. In the picture above the environment has changed since a road has been made, destroying the ladybug's habitat. The variation is created by the overproduction of offspring.
Since the orange ladybugs blend in better with their surroundings they are more likely to survive against the predators which causes selection.
This has created an adaptation in the gene pool and caused the orange ladybugs to thrive.
This is how a species can evolve after a change in an environment.