托福口语 Task 4

Today, we're going to talk about a fascinating concept in animal behavior called 'sensory exploitation.' This is the idea that a signal—like a visual display or a sound—evolves in one species because it taps into an existing sensory bias in another species, usually a mate or a predator. The signal essentially exploits a pre-existing preference, not something newly evolved. Let me give you two classic examples. First, consider the water mite. The male water mite performs a waving motion with his legs near a female. This isn't just random—it mimics the movement of a small prey item, which female mites naturally detect and are drawn to. So, the female's innate predator-detection system is hijacked to attract her for mating. Second, think about the túngara frog. The male's call includes a 'chuck' sound that is very similar to the low-frequency vibrations of a predator, like a bat. Female frogs are already attentive to such low-frequency sounds because they signal danger. By exploiting this, the male's call is more attractive to females, even though it also increases the risk of attracting bats. So, in both cases, the signals evolve to match what the receiver's brain is already wired to notice.