The species most likely to adapt and evolve to the changed environment on the island, given the described conditions, would be the insect species with high reproduction rates and a significant mutation rate.
High reproductive rates allow for a larger number of offspring, increasing the likelihood of some individuals possessing traits that may be advantageous in the new conditions. Additionally, a significant mutation rate can introduce genetic diversity, which can lead to the emergence of beneficial traits that help the species adapt to lower temperatures and reduced sunlight.
In contrast, the other species (large mammals and birds) have low reproduction rates and specific needs, making them less adaptable to rapid environmental changes.