托福口语 Task 4

Today we're going to talk about a fascinating concept in animal behavior called 'sensory exploitation.' This is when a signal in one species evolves to exploit a pre-existing sensory bias in another species, often to the sender's advantage. The key point is that these biases existed before the signal evolved—they weren't created by the signal. Let me give you two examples. First, consider the water mite. Male water mites perform a waving dance in front of females. This dance mimics the vibrations of a small prey animal. Female water mites are naturally attracted to these vibrations because they signal food. So, the male's dance triggers the female's feeding response, causing her to approach and mate. Second, think about the túngara frog. Male túngara frogs add a 'chuck' sound to their call to attract females. Female frogs have a pre-existing auditory bias for low-frequency sounds, which in their environment are often made by larger, more dominant frogs. By adding the chuck, the male exploits this bias, making himself sound larger and more attractive, even though he's not actually bigger. So, in both cases, the signal works because it taps into a sensory system that was already there.