What did Sarah Gravem and colleagues study regarding sunflower sea stars?

• A. Their mating habits
• B. Their feeding preferences when given nutritionally varied purple sea urchins
• C. Their migration patterns
• D. Their reproduction rate

Answer: (B)

Focusing on how predators decide what to eat, the key idea is that prey quality can steer foraging choices. Sunflower sea stars prey on sea urchins, so studying them reveals whether a predator favors higher-energy, more nutritious prey. Gravem and colleagues investigated this by presenting sunflower sea stars with purple sea urchins that varied in nutritional value and observing which urchins they attacked or consumed. If the stars prefer nutritionally richer urchins, it shows that prey quality influences feeding decisions, consistent with the idea that predators aim to maximize energy intake relative to effort. This kind of work helps explain how differences in prey nutrition shape predator-prey interactions in marine ecosystems. In short, the study looked at feeding preferences when prey differed in nutritional value.