【英语时差8,16】利用紫外线的鱼（在线收听）

So you want to attract mates. After all, passing on your genes is what evolution is all about. To do that you need offspring, and to get a lot of those you need to be attractive. The flashier the better. Hey, look over here! Sexy me. Ah, but there’s the problem. The flashier you are, the more likely you are to attract predators. Hey, look over there–that guy really stands out. I’ll eat him. This is a pickle. How to be flashy in the eyes of mates but subdued in the eyes of predators? New studies show that swordtail fish have evolved a clever solution: use ultraviolet light. These innocuous little critters actually shine brightly in stripes that run along their flanks… but only if you look in the UV wavelength. Researcher Molly Cummings and her coworkers at the University of Texas at Austin placed a female swordtail in a tank with two males visible at either end. One of the males, however, was surrounded by filtering glass that blocks UV light. They found that the female was twice as likely to demonstrate interest in the male whose UV flashers were visible to her. Twice as likely! That’s a big finding.