【英语时差8,16】蚂蚁突袭（在线收听）

Imagine this. You’re coming home to your gated community after a long day of work. As you stop to show the guard your ID, a mugger jumps out from behind a bush and grabs you by the mouth. Okay, that last part sounded a little weird, but that’s pretty much the way it happens to sweat bees. These are the little metallic-looking critters who live in nests burrowed into the ground. Some bees go out foraging, but one stands by the entrance to the nest. She doesn’t let anyone in unless he can identify himself using a chemical tag. The returning bee is most vulnerable when it’s waiting for the ID check. Sure enough, entomologists have observed another species attacking at just that moment. Ectatomma ruidum–ants. E. ruidum charges the waiting bee, grabs its mouthparts, hauls it away and kills it–now somebody else will be bringing home a little snack. What’s a bee to do? Two French researchers have recently spotted sweat bees changing their flight paths when an ant is lurking by the hole. According to the study, bees have been seen pulling up at the last minute and later try coming in from a different direction. Others land far away from the hole and then dash in on foot. Researchers found that even a dead ant with its odor removed is enough to spook the bees. This is an impressive feat, showing that sweat bees are somehow able to understand the danger posed by ants. But it’s also eye-opening to realize how much strategy and counterstrategy is involved in the daily lives of even the smallest insects.