This Is Why Water Striders Make Terrible Lifeguards | Deep Look

This Is Why Water Striders Make Terrible Lifeguards | Deep Look


To us, water striders are almost magical. I mean, come on, they’re literally walking
on water. But come down to their level and it’s a
bit more… sinister. These delicate little bugs have figured out
how to master the elements – and to exploit those who can’t. So how do water striders float where others
sink? The answer is those crazy long legs. Water is pretty sticky stuff. It likes to hold onto itself. It sticks together especially well right at
the surface. If you’re small, it can actually hold you
up, as long as you don’t break through that surface tension. It seems like the water strider’s legs would
just sink right in. But they don’t. They make dimples on the surface. That’s because their legs are covered in
tiny hairs called micro-setae that repel water. The strider’s entire body is covered in
them. Those hairs trap a layer of air that keeps
the water from sticking to its body. The water strider simply can’t get wet. That’s how they can sit on top of the water
without breaking through. Plus they’re pretty light and they spread
out their weight with their front and back legs. They use their middle pair of legs to maneuver,
by pressing down and back against those dimples. Just like rowing a boat. They can even catch some air. Most of their fellow insects aren’t quite
as graceful. Like this caddisfly. Struggle as it may, it’s stuck.. half-drowned… Exactly what the water strider has been waiting
for. It probes for a weak spot And pierces through – spitting digestive enzymes
in that dissolve its victim from the inside. Then the striders take their time sucking
out the innards. Leaving the caddisfly a dried-out husk. The stream delivers an endless buffet of new
victims. Because for most, that razor-thin line between
water and air is a treacherous place. But water striders know: keep your feet dry and you’ll always have
the upper hand. Hey there, it’s Lauren. I know you see that subscribe button there. Here’s what it’ll get you – new Deep Look
episodes every two weeks. Keep up with all the weird, gross and wonderful
things we’re working on. Thanks and see you soon.

Meet the Dust Mites, Tiny Roommates That Feast On Your Skin  |  Deep Look

Meet the Dust Mites, Tiny Roommates That Feast On Your Skin | Deep Look


Long ago — around the time we started growing
our own food – humans settled down. We went home, inside. We built permanent shelters to protect us
from the elements… and keep the wild animals at bay. Or so we thought. Surprise! The animals were right there with us. They
still are. This is dust. Zoom in and you find an ecosystem almost as
elaborate as the one we left outside. But small enough for us to forget it exists. Dust is pretty much anything small. But the most important ingredient of dust
— at least for the purposes of this story — is skin. Your skin. Her skin. His skin. Tiny flakes that fall off our bodies.. all
day long. Researchers at The California Academy of Sciences
in San Francisco collect and study house dust to find out what, exactly makes up this micro-universe. Even the cleanest homes are teeming with tiny,
almost invisible roommates. — and even more so if you have pets or kids
or live on the ground floor. Most homes have over 100 species – no matter
how often you vacuum. Not just these guys,
but these and these. Most of these microscopic roommates are harmless. Just freeloaders, basically. But one can cause real trouble: the house
dust mite. This is like the roommate who leaves his crap
around and makes you sick. Dust mites don’t bite people. They don’t need
to. We feed them. Constantly. Skin flakes are hard to digest. It’s like eating hair or feathers. So dust mites have powerful digestive enzymes
to break the skin down. Those enzymes turn up in dust mite poop. And let’s just say you probably don’t want
to know how much dust mite poop is in your house.. When people breathe dust, they breathe in
the poop — and the enzymes, too — which irritate the lungs and can aggravate asthma,
especially in kids. Like us humans, dust mites haven’t always
lived inside either. These tiny relatives of spiders and scorpions
once lived in birds nests. But then, some intrepid dust mites made the
jump… from bird’s homes, to ours.. And as our society thrived and grew, so did theirs. Hi – this is Amy. So while you marvel at this lovely pyroglyphid,
I have a favor to ask. Our partner PBS Digital Studios wants to hear
from you. It’s a survey, so we can make even better
shows. It’ll take a few minutes, but, a few lucky
people will get a free PBS Digital Studios T-shirt. Just click the link below. Thanks, and thanks for watching.

For These Tiny Spiders, It’s Sing or Get Served | Deep Look


Behold a very small and rather cute spider. This is clypeatus. A jumping spider. He doesn’t spin webs. Instead he uses silk as a lifeline, reeling
it out as he hops from place to place. But right now, he’s looking for a mate. The thread of a female spider that he can
trace back to its source. Problem is, she may have other priorities. While he’ll jump on pretty much anything
that moves…She only mates once. She’s picky. So he’s going to make his case… on the
dancefloor. Male jumping spiders perform courtship displays
that would make Bob Fosse proud. Jazz hands, leg-lifts…they even shimmy their
pedipalps. But he needs a soundtrack. So, by beating together the front and back
halves of his body, he creates vibrations that travel through the ground. This is what her ears look like. Tiny membranes stretched across slits in her
legs. To study these jumping spider pulses, researchers
at the University of California Berkeley use a sophisticated laser vibrometer developed
for quality-testing cars and airplanes. It turns those vibrations into something we
can hear. And guess what? It’s a song. The first verse sounds like this. A fast heartbeat. Thump thump thump thump thump thump thump. Then, more thumping. Followed by something new. A “BOOM.” This is verse two. That pattern, over and over again. For verse three he adds a third element. Almost like he’s casting a spell, right? From species to species, and there are thousands
of different jumping spiders, the songs vary. But one thing never changes: Male jumping
spiders sing like their lives depend on it. Because they do. She may mate with him. She might refuse. But she might just eat him instead. When the Berkeley scientists prevented the
males from singing while they danced, the females were three times as likely to hunt
them as prey. So he needs to go big. The closer he gets to her, the more danger
he’s in. The dance and the song get more and more urgent. But even with all that… She’s still calling the shots. Hi, it’s Amy. If female spiders are picky, with males, the
bar is so, so low. He’ll do this courting song and dance with
pretty much anything. In the lab, scientists use frozen specimens
this one. A dead female spider! And he still tries to mate with her. While you’re here, subscribe to Deep Look,
and thanks for watching.