In my last question, I have asked on how, once Mars has been terraformed, Terran species of plants and the insects on which the majority of them rely on would adapt to Mars's longer year. By far, the only answer I got is to start the pioneering at the equator, where there won't be any seasons to worry about, and the plants can grow, blossom and be pollinated by insects without problem.
But Earth-based plants on Martian soil can't stay in the equator forever!
This question is particularly important not just here, but in any terraforming project involving dumping Earth-based species on any Earth-like habitable rock orbiting a star of any type from a distance greater than one AU (basically speaking, any orbit so far away that one year lasts more than 365 days.) Once the plants and insects have been established at Mars's lower latitudes, how long would it take them to colonize as much of the rest of the planet as they can?
This is not a question that involves evolution, which would take too long. The reason I'm focusing on the plants and insects is due to their interconnected relationships, and how the other animals rely on them as well.