Thual reproduction, the species can produce offspring with a range of beak sizes and shapes, allowing some individuals to have the advantage of cracking seeds and survive even when the bug population is eliminated by the invasive species
This is an example of adaptive radiation, not "thual" reproduction. Adaptive radiation refers to the diversification of a single ancestral species into multiple different species that occupy different ecological niches. In this case, the ancestral species with the range of beak sizes and shapes is able to exploit different food sources (seeds in this case) and survive even when one food source (bugs) is eliminated by the invasive species. This adaptation allows certain individuals within the species to have a selective advantage in the changed environment, leading to their survival and successful reproduction.
