Genome sequencing, Evolutionary studies of Chrysolina angusticollis.

Adaptive radiations are a rapid evolutionary process that occurs in conjunction with the ecological environment and trait diversification. Much of the research on adaptive dissipation that has developed in recent years has relied on interpretations of the correlations found between current diversity patterns and ecological factors, often overlooking the contribution of non-adaptive factors such as past geographic isolation. In this study, we propose that geographic isolation, which is a non-adaptive factor, can occur due to biological interactions rather than non-biological factors such as crustal and climate change. A novel process by which closely related species interact with each other to geographically divide each other is named "Biotic Population Subdivision (BPS)" and a wild population of Chrysolina angusticollis, which lacks the ability to fly, is used to test the hypothesis. The Hokkaido population of the species can be divided into nine major morphological types, and is considered to be a "species complex" with markedly diversified body coloration and genital morphology. Using this species as an actual example, we will investigate the repetitive origination of isolated populations and speciation in a continuous space using molecular phylogenetic analysis by whole-genome sequencing and RAD-seq data, laboratory mating experiments and mathematical models.