托福口语 Task 4

Today, we're going to talk about a fascinating concept in biology called 'mimicry for protection.' Now, mimicry is when one species evolves to resemble another, often to avoid predators. There are two main types: Batesian mimicry and Müllerian mimicry. Let me give you examples from the insect world. First, consider the harmless hoverfly. It has black and yellow stripes, very similar to a wasp. Wasps are dangerous because they can sting. So, predators like birds learn to avoid anything with those warning colors. The hoverfly, though harmless, benefits from this because birds mistake it for a wasp and leave it alone. That's Batesian mimicry—where a harmless species imitates a harmful one. Now, for Müllerian mimicry, think about two species of stinging bees. Both have similar bright orange and black patterns. Both are actually dangerous—they can sting. But by looking alike, they share the cost of teaching predators. A bird that gets stung by one bee learns to avoid all bees with that pattern, benefiting both species. This reduces the number of individual bees sacrificed to educate predators. So, in both cases, mimicry enhances survival, but the mechanism differs: one is a bluff, the other is a shared warning.