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 male animal evolves a trait that appeals to a pre-existing sensory bias in the female, not because the trait indicates quality, but simply because it triggers a response that already exists. Let me give you two examples. First, consider the swordtail fish. Female swordtails naturally prefer males with longer bodies, even before swordtails evolved their sword-like tail extension. Researchers found that females of a related species without swords also prefer males with artificial swords attached, showing the preference predates the trait. Second, think about the water mite. Male water mites perform a waving motion with their legs to attract females. This motion mimics the vibrations of a copepod, which is the female's prey. The female's hunting instinct causes her to approach, and the male then mates with her. So, in both cases, the male's trait exploits a sensory bias that already exists in the female for other reasons, not because it signals fitness.