托福口语 Task 4

Today, we're going to talk about a fascinating phenomenon in animal behavior called 'sensory exploitation.' This is when a species evolves a trait that exploits a pre-existing sensory bias in another species to gain a reproductive advantage. Let me give you two clear examples. First, consider the male túngara frog. Females have an innate preference for certain low-frequency 'chucks' in calls because they resemble the sounds of their predators, which may help them locate safe areas. Males exploit this by adding a 'chuck' to their call, making them more attractive to females. However, this also increases the risk of being eaten by bats, which are attracted to the same sound. Second, look at the water mite, a tiny aquatic insect. Male water mites use their legs to wave in a specific pattern that mimics the vibrations of a struggling insect on the water's surface. Female water mites, which are predators, have a built-in sensory bias to detect these vibrations to find prey. The male's display triggers this predatory instinct, causing the female to approach eagerly, which then facilitates mating. So, in both cases, the males are not just advertising their quality; they are hijacking a pre-existing sensory system that evolved for other purposes, like predator avoidance or feeding.