雅思听力

🎧 Listening Transcript

Today in our biology lecture, we will discuss the migration patterns of monarch butterflies. Every year, millions of these butterflies travel from North America to central Mexico, covering up to 3,000 miles. Interestingly, the journey is not undertaken by the same individuals. Instead, it takes four generations of butterflies to complete the round trip. The first three generations live only a few weeks, but the fourth generation, born in late summer, has a lifespan of up to eight months. This special generation makes the long journey south and then returns north in spring, laying eggs along the way. Understanding this cycle is crucial for conservation efforts.