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From ripping your own appendages off to cockroach mind control, wasps go to great lengths to ensure the survival of their species.

Hosted by: Hank Green
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Sources:
http://animals.nationalgeographic.com/animals/bugs/wasp/

Fig wasps:
http://www.sciencedirect.com/science/article/pii/S0960982205014661
http://www.bbc.co.uk/earth/story/20160429-a-tale-of-loyalty-and-betrayal-starring-figs-and-wasps
https://askabiologist.asu.edu/figs-without-wasps

Fairy wasps:
http://www.sciencedirect.com/science/article/pii/S1467803911000946
http://blogs.discovermagazine.com/notrocketscience/2011/11/30/how-fairy-wasps-cope-with-being-smaller-than-amoebas/#.WQinO1Pytxw

Jewel wasps:
https://www.scientificamerican.com/article/how-a-wasp-turns-cockroaches-into-zombies/
https://academic.oup.com/icb/article-lookup/doi/10.1093/icb/icu006
Wasps have a pretty bad rap: nobody wants yellow jackets pestering them at picnics. It’s not like they make honey... they just sting you!

But there’s around 30,000 species of them, more than all known mammals and birds combined! Some are stunning to look at, while others have ridiculous names like “gasteruption jaculator” or “aha ha.” And some wasps go to pretty extreme lengths to survive and reproduce: getting trapped in figs, destroying their own nervous system, and cockroach mind-control!

You probably know bees are great pollinators. And some wasps are too, like the fig wasp! They’ve lived, mated, and died inside figs for millions of years, driving a complicated evolutionary relationship. A young fig is actually a bunch of tiny flowers folded inside a pod. There’s a small opening at the bottom of the pod just big enough for a female fig wasp to crawl into.

In fact, it’s such a tight squeeze that her wings and antenna are usually ripped off of her body as she climbs in. But it’s not like she’s going to need them anymore. She lays an egg inside each fig flower, which serve as little incubators. Then, she dies – helpless and trapped, but her job complete.

The baby males emerge first, chewing holes into the leftover flower-incubators and impregnating the females before they even hatch to set up the next generation. The males are wingless, and can’t survive outside. But they dig tunnels out of the fig to help the emerging females escape, so they can start the cycle over again.

Now, what does the fig get out of this deal? Well, the same thing: reproduction! Figs can be male or female, too. And fig wasps can only lay eggs in male figs, which produce pollen. The shape of the flowers in female figs, which receive pollen, prevents it.

So basically, every female fig wasp is born coated in the pollen of a male fig flower. So it’s not great for her if she ends up in a female fig, but it IS good for the fig! So that female wasp will have some pollen stuck to her from the male fig she hatched in, so it pollinates the female fig she ended up in, even though she can’t lay eggs in there, before she dies.

So the fig can mature into a tasty fruit, and an animal can eat it and disperse the seeds. And it works out for everybody, except for that one particular female fig wasp.

Now, wasps come in all shapes and sizes. The biggest are Asian giant hornets, whose queens can reach 5 cm. But others rarely grow larger than one millimeter long! They’re too small for most predators to bother them, and they’re tiny enough to lay their eggs in other insect eggs to take advantage of someone else’s delicious nutrients.

And they’ve pulled some nifty tricks to pack thousands of cells into a teeny-tiny body. Take this wasp with a mouthful of a name: Megaphragma mymaripenne, which is the third smallest insect we know of. It has a full body with organs and nerves, but it’s about the same size as an amoeba – a single-celled organism!

To stay small as it matures into an adult, it destroys nearly all the DNA-containing nuclei from its neurons... and somehow survives! We used to think all cells need DNA in order to make proteins, and carry out all the processes that keep animals alive and functioning. But even with its ravaged nervous system, these wasps can still fly, mate, lay eggs, and survive for five whole days into their adulthood – which isn’t an unusually short lifespan.

Some researchers think that this wasp might make all the proteins and stuff its neurons need to survive for those five days just before becoming an adult and bursting its nuclei. But it’s still kind of a mystery, and there might be a lot we can learn about the bare minimum for survival from these thrifty little critters.

This female jewel wasp may look snazzy, but don’t be fooled, she uses literal mind control to get what she wants: live cockroach flesh for her babies. When she finds a roach, she hits it a one-two punch of a venom cocktail. The first sting to the thorax temporarily disables its front legs, and the second targets specific cells in the cockroach’s version of a brain.

The venom isn’t deadly, as she, unlike me, doesn’t want to kill the roach... just change its behavior. Probably because of dopamine laced into the injection, the cockroach suddenly gets obsessed with cleaning itself. The venom also screws with its opioid system, making it much less responsive and less easily startled.

So even though it has a clear size advantage, it doesn’t put up a fight. After about half an hour, the zombified roach’s legs recover enough to let the wasp lead it to its final destination: an underground burrow she has prepared while the roach was busy grooming. Once inside, she leaves the roach with a parting “gift": a single egg laid inside its body. Then she seals the tomb and goes off to find another victim.

There’s nothing the trapped roach can do. The venom keeps it in a stupor, but it stays alive long enough to feed the new larva growing inside of it, beginning the next generation of cockroach mind-control!

If you want to learn more tiny stinging insects, you can watch our video where I talk about the difference between wasp nests and beehives. And don’t forget to go to youtube.com/scishow and subscribe for more of this, every single day