托福口语 Task 4

Today we're going to talk about a fascinating concept in animal behavior called 'sensory exploitation.' This occurs when a species evolves a trait that exploits an existing sensory bias in another species, often for the purpose of attracting mates. The key idea is that these traits don't create new preferences; they tap into pre-existing ones. Take the guppy, for instance. Female guppies have a natural preference for orange-colored objects, likely because in their natural habitat orange signals food. Male guppies, over time, have evolved bright orange spots on their bodies. When a female sees these spots, her food-related sensory bias is triggered, making her more likely to approach and mate with the male. Another example comes from the túngara frog. Female túngara frogs are attracted to the 'whine' part of the male's call, which is a basic call all males produce. However, some males add an extra 'chuck' at the end. This 'chuck' exploits the female's auditory bias for low-frequency sounds, which in their environment might indicate a larger, more fit male. So these males with the 'chuck' have a mating advantage.