Which of the following are examples of frequency-dependent selection strategies observed in the roseate tern?

Frequency-dependent selection occurs when the fitness of a phenotype is dependent on its frequency relative to other phenotypes in a population. This phenomenon can create advantages or disadvantages based on how common or rare an individuals' traits are in the population at any given moment.

In the context of the roseate tern, the distinction between fish-hunters and fish-stealers provides an excellent example of this concept. Here, fish-hunters actively pursue and catch fish, while fish-stealers take advantage of the efforts of fish-hunters by stealing the fish that they have caught. When one strategy becomes more prevalent, it can influence the success of the other. For instance, if fish-hunters become too common, fish-stealers may thrive because they can easily locate fish being caught. Conversely, if fish-stealers dominate, the fish-hunters may experience increased success as the stealing behavior becomes less beneficial. This dynamic interaction illustrates the principles of frequency-dependent selection.

In this case, the roles of fish-hunters and fish-stealers exemplify a situation where the success of each strategy is influenced by the frequency at which it appears in the population, showcasing frequency-dependent selection in action.