字幕表 動画を再生する 英語字幕をプリント Thanks to Brilliant for supporting this episode of SciShow. Go to Brilliant.org/SciShow to check out their Knowledge and Uncertainty course! [♩ INTRO] No one wants to be eaten. That's why the animal world is full of adaptations to stop predators — like hard shells, bright markings, and painful stings. Still, most creatures regularly end up on someone's menu—except for velvet ants. These little insects combine a ton of defenses into one very unappetizing package. And they're so terrifying that pretty much nothing eats them! Velvet ants aren't technically ants; they're wasps. The males can fly, but the females don't have wings. What they do have is a massive stinger! In fact, relative to their size, they've got the longest stinger of any wasp! And some seriously painful venom, too. Still, they don't rely on it alone to deter predators. They also have a super-tough exoskeleton. It takes about five times the force to crush a velvet ant as it does to squish a bald faced hornet, for example. Plus, they're round and slippery, making them hard to bite down on… something researchers realized firsthand while trying to crush these things. The critters kept slipping out of their grasp! Of course, the velvet ant doesn't want it to come to that. So, they employ an array of warning signals. Their “velvet” sections are brightly colored, as a bold, visual aposematic signal. They also literally sound the alarm by rubbing a section of their abdomen to make a loud squeaking noise. And they can release smelly alarm pheromones! These by themselves can deter some predators. And the combinations of defenses and warnings is super effective; it seems to train other animals not to mess with them, too. Like, in one experiment, lizards that had a run in with a velvet ant still avoided them over a year later. And in another, birds were wary of eating one of their favorite tasty treats simply because researchers had painted them to look like velvet ants. Predators don't even need to have encountered a specific species of them. Many velvet ants mimic each others' coloring, in what scientists call Müllerian mimicry. So if a predator encounters one, they're unlikely to mess with any of the others! In fact, scientists have set up showdowns between velvet ants and many potential predators, just to see what bites. They tried spiders, lizards, actual ants, birds, moles, gerbils, shrews... Almost all of them avoided the velvet ants entirely. And the few that did catch them mostly spat them up! As far as anyone can tell, toads are the only animals that occasionally eat velvet ants. But they don't have an easy time of it. They swallow their food whole, and velvet ants can survive for over 20 minutes inside a toad's stomach! So even toads end up spitting them out more often than not. Velvet ants' extreme investment in defense likely has something to do with their lifestyle. Females can't fly away from predators. Plus they spend lots of time on the ground looking for places to lay their eggs. See…These ants are parasites. To reproduce, they find nests of other bees and wasps and lay their eggs inside. When the larvae hatch, they feed on the other species' helpless young. Oh, also: those nests are often well-defended by other stinging insects. So I guess if you're regularly that rude to your neighbors, you'd better be as tough as a velvet ant! We humans will never be as hardcore as velvet ants. But we can master some hardcore STEM skills with a little help from Brilliant! Brilliant offers dozens of engaging, interactive courses in math, science, and computer science. For example, their Knowledge and Uncertainty course teaches cutting edge math like information theory and bayesian networks, but in a super fun way—like by solving puzzles! And right now, if you're one of the first 200 people to sign up for an annual premium subscription at Brilliant.org/SciShow, you'll get 20% off! Which is a pretty sweet deal. [♪ OUTRO]
B2 中上級 米 昆虫は何も台無しにしない:ベルベットの蟻を満たす (The Insect Nothing Messes With: Meet the Velvet Ant) 5 2 Miho Ishii に公開 2021 年 01 月 14 日 シェア シェア 保存 報告 動画の中の単語