In this video, I demonstrate how surface tension works in the lab. These predators eat any non-aquatic insects that somehow get trapped in the chaos of the “air-water interface”.
Do you know how their eggs survive the winter freeze? Fish can not eat water striders because they have such fast reflexes. Also, they are bitter-tasting hairballs!
Here’s a video of cool facts about water striders, but if you like to read, scroll past the video for the full text:
10 COOL FACTS ABOUT WATER STRIDERS
Did you know these insects are actually heavier than water? Ordinarily, objects with a greater density than water should sink like metals would.
However, water striders defy this physical law by combining several brilliant adaptations. Today we dive into the bizarre biomechanics and behaviors of the bugs that walk on water
10. Jesus bugs and shadows
Adult water striders are classified as AQUATIC insects but don’t live IN the water. Instead, they literally walk ON TOP of it and have earned the nickname “Jesus bug.”
As you can see in this image, a water strider is physically bending the water itself into six dimples around its limbs. In turn, this curved water bends light just like a magnifying glass. Shadows are cast on the substrate below.
In fact, the easiest way to spot a wild water strider is to go down to your local pond, puddle, or vernal pool and watch for these signature dancing shadows.
9. Surface tension manipulators
Water striders spend most of their time in the chaotic boundary where air meets water. “The air-water interface.” A cohesive force called “surface tension” is strong at work.
You may not know it, but water likes to stick to itself.
On a microscopic level, the water’s surface physically forms an elastic membrane that behaves like a trampoline. If you are small enough, you can jump on this trampoline. But if you jump too hard, you might rip the membrane and fall right through!
8. Floating like metal? (You’ll have to watch the video on YouTube to see the lab demo!)
Water striders are “heavier” than water, so they should sink like a rock! But these long legs and flat feet allow the unexpected to happen.
Let’s go to the lab and play with some paper clips.
This red paper clip is metal and sinks in water… duh! But if I gently place it above the surface, look at that; it floats!
I am not a sorcerer. What’s happening here is that the water molecules are clinging together so tightly that they don’t allow the paper clip to slip between them and sink.
Just for funsies, I bent 4 paper clips and stuck them together with a single drop of super glue.
This shape mimics the anatomy of a water strider, but let’s say my model is inferior to their natural powers. Water striders can actually carry 15 times their own weight without breaking the surface tension.
BONUS FACT: Did you know about the “Halobates” ocean strider?
There are over 1 million insect species known today. The “Halobates” water striders are the only insects that live in the open oceans.
Incredibly, these “ocean striders” inhabit over one 3rd of the globe’s surface.
7. Hairs that “hate” water
Under the microscope, you can see that water striders are covered in “hydrophobic” hairs. “Hydro” means “water” and “phobic” means “fearing.” But why exactly do these hairs “hate” water? It’s because they are covered in a special oil that repels polar molecules.
All oil, including this cooking oil, dislikes being around water. If you put a drop in water, it clearly doesn’t mix. Instead, it balls up.
Oil molecules have no charge, so water dislikes being around them. Instead, a water molecule will push oil out of the way until it finds as many fellow water molecules as possible to call happy neighbors.
This oil-coated hair prevents the water strider from becoming water-logged. It can slide over the surface like a waterproof surfboard instead of getting bogged down like wet toilet paper.
6. Bug juice smoothies
As strict carnivores, what do water striders eat?
They specialize in capturing any non-aquatic bugs that somehow end up in the chaos of the “air-water interface”.
Dragonflies might accidentally get stuck when laying their eggs. Beatles or ants could fall out of a tree. Look at this wasp, and it doesn’t have the proper shape or oily hairs to escape the sticky situation.
It attacks when a water strider finds one of these half-drowned bugs or a dead bug. First, a needle-like proboscis pierces the prey’s abdomen. Then a digestive enzyme is injected. This breaks down the prey’s internal proteins into a goo,
which can be sucked out like a bug juice smoothy!
Yummy… Too bad nature forgot to give this spider swimming lessons.
5. Survival superpowers
Water striders are predators. However, their small size means that they are also a prey item. An especially formidable foe of the water strider is the backswimmer.
Backswimmers are their evil mirror-imaged nemesis. They operate on the opposite side of the “air-water interface.” While swimming around upside down, backswimmers attack from the bottom up.
Birds, frogs, and fish also sometimes try to eat water striders, but water striders don’t make for a delicious snack.
They are little more than bitter-tasting hairballs. Lacking flavor is just one of the water strider’s natural defenses.
Safety in numbers? Check! A reaction speed 20x faster than that of us measly humans? Check! Jumping six times your own height? Check!
Six times? That’s like me jumping out of a swimming pool and over my childhood house in a single bound.
Water striders are elusive, and this fish has learned that attempting to gulp one down directly is futile. Following the water strider to its next victim and stealing the meal will be easier.
In fast-moving water, water striders can even switch off that flashy “walking on water” mode and turn on a more subtle “rowing” mode. Ironically, the only thing these athletic aquatic insects can’t do is swim!
4. Ripple detectors
Like spiders in a web, water striders have a 6th sense. They can use their front legs to detect the direction of incoming waves. Struggling prey emit rings of ripples that broadcast their location and lead water striders right to them.
Water striders are social creatures, and these ripple detectors are also used for transmitting information.
By drumming at unique frequencies, ripples can communicate territory, readiness to mate, the presence of food, or the presence of a predator. A water strider population is all networked together and sharing data.
3. Grabbing her eyes?!
Water striders do everything on the water, and that includes doing IT. Mating on the water can be bumpy, so the males have evolved a pair of specialized antennas.
The antennas are barbed and shaped like spanner wrenches. Unfortunately, they fit perfectly around the female’s eyes and can be latched in place.
Additionally, some males are hyper-aggressive. They often attempt to reproduce with the wrong species or even with dead bugs that should be seen as food.
Come on, guys. Try it. Think with your brain, not your dorsal fin!
2. A deadly winter
Water striders give birth to three generations in one calendar year. Right before winter, the surviving females lay eggs on aquatic plants. As the cold weather sets in, all adults either starve, freeze to death, or die of old age.
However, when this lily pad dies, it sinks to the bottom of the pond, taking some water strider eggs with it. Since only the top few inches of a pond freeze, these eggs are now safe from any ice down in the muck below.
The water strider life cycle begins when water temperatures finally warm up in the spring. Nymphs are born carnivorous and start eating right away.
Only 10% of the population survives to adulthood because growing up involves a struggle for calories.
To win the competition, stronger individuals sometimes cheat by canalizing their siblings!
1. The enemy of my enemy…
Water striders might scare the bejesus out of you from time to time, but stay calm! They don’t bite humans, nor do they don’t transmit any human disease.
In fact, you should welcome water striders into your friendly neighborhood swamp. These helpful insects actually kill the natural enemy mosquitoes!
The World Health Organization estimates that 725,000 people die yearly from mosquito-borne diseases.
Luckily, mosquitoes lay eggs in the same ecosystems that water striders patrol.
According to one laboratory study, the average water strider can eat 14 mosquito larvae per day. So, if you see water striders around, count your lucky stars and protect them.
“The enemy of my enemy is my friend!
I hope that you enjoyed this article and my video of cool facts about water striders. Last time, we talked about cool facts about sloth, if you haven’t seen it, bookmark to watch later.
Head to my Youtube playlist where you can choose between animal facts, animal education , and animal news.
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