Which type of selection is exemplified by the success of both the dullest and brightest male lazuli buntings?

Disruptive selection is a type of natural selection that favors individuals at both extremes of a phenotypic trait over those with intermediate phenotypes. In the context of the lazuli buntings, this selection is evidenced by the success of both dull and bright males in reproductive scenarios.

Dull males may have an advantage in certain environments where being less conspicuous allows them to avoid predators, while bright males are more likely to attract females due to their vibrant coloration. This situation leads to a bimodal distribution of male coloration within the population, as both extreme phenotypes are beneficial under different circumstances. The presence of two successful strategies (dull and bright males) illustrates how disruptive selection can maintain diversity within a population by favoring these different adaptations.

This kind of selection contrasts sharply with other forms such as stabilizing selection, which tends to favor intermediate traits and reduce variability, or directional selection, which favors one extreme trait over others.