In the late 1990s and early 2000s, the Human Genome Project spent years decoding DNA from a handful of donors. The work was painstaking and slow, given DNA sequencing technology of the time. Today the same analysis goes much faster (and is much cheaper), thanks largely to microfluidic devices that automate steps that once had to be done by hand. Microfluidic devices have also made their way into medical diagnostics — pregnancy tests, at-home COVID tests, and blood glucose strips used by diabetics are common examples — as well as experimental biology. The Scientists has a nice review covering some of the many ways these devices have revolutionized the field. (Image credit: CDC; see also The Scientist; submitted by Marc A.)
Tag: biology
How Ferns Spread Themselves
Ferns don’t rely on pollen and pollinators to spread. Instead, they use a little water and a lot of ingenuity, as shown in this video from Deep Look. Peer underneath a fern and you’ll find leaves dotted with spores. As they mature, water evaporates from the sporangium, eventually triggering a catapult that launches the spores. Those spores grow little gametophytes that produce the fern’s sperm and eggs; given a little rain or a nice puddle, the sperm and eggs can find each other and trigger the birth of a new baby fern. (Video and image credit: Deep Look)
“Divebomb”
Seabirds like gannets and boobies are engineered for diving. They fly to a certain altitude, locate fish underwater, and then fold themselves into a streamlined projectile. With this, they plunge into the water at high-speed, positioned to protect themselves from the forces of impact. Under the water, they dart among their prey, hunting with singular purpose. Photographer Kat Zhou’s “Divebomb” captures the underwater side of this behavior, while showing off the energetic bubbles (and bubble rings!) created by the birds. (Image credit: K. Zhou; via UPY 2024 and Colossal)
How Moths Confuse Bats
When your predators use echolocation to locate you, it pays to have an ultrasonic deterrence. So, many species of ermine moths have structures on their wings known as tymbals. These areas have a band of ridges, and, when the moth’s wing lifts or falls, the ridges buckle one-by-one. A nearby bald patch on the wing acts as an amplifier, making these ultrasonic snaps louder. Altogether, the mechanism deters prowling bats anytime the moth flaps its wings — without any additional effort on the moth’s part. Since the moths have no ears, they presumably don’t even know that they’re making the sound! (Image credit: Wikimedia/entomart; research credit: H. Mendoza Nava et al.; via APS Physics)
Mimicking Plant Movement
Many plants control the curvature of their leaves by selectively pumping water into cells that line the outer surface. This swelling triggers bending. Engineers created their own version of this structure by 3D-printing trapezoidal shapes onto a fabric. Then, they heat sealed a second layer of fabric over this, creating airtight channels. When inflated, these channels make the structure bend, allowing them to create complex shapes by selectively inflating different areas. (Image credit: T. Gao et al.; via GoSM)
“Mason Bee at Work”
Mason bees like this one build landmarks to help them navigate as they construct a shelter for their eggs. Even hauling materials, these bees can easily stay aloft. This is in contrast to an old misconception that physics can’t explain how a bee flies. It’s true that bees don’t fly using the same mechanisms as a typical airplane — no fixed wings here! But they, like every other flyer aerodynamicists study, still produce lift and drag and thrust. The flapping of a bee’s wings generates much unsteadier quantities of these things, but at its small size, that is no hindrance to its ability to control its flight and even carry cargo. (Image credit: S. Zankl; via Wildlife POTY)
Sharpshooters
The sharpshooter‘s superpower is pee flinging. These insects consume nutrient-poor plant sap, so to get the calories they need, they have to drink 300 times their body weight each day. All that extra liquid has to go somewhere, so the sharpshooter evolved to be an expert excretor. Each drop gathers on their anal stylus, then gets launched with an energy-efficient flick. During that move, the sharpshooter compresses the droplet, adding a little extra energy that helps speed up the drop’s flight once launched. (Video and image credit: Deep Look)
Surviving Rainfall
Water striders spend their lives at the air-water boundary, skittering along this interfacial world. But what happens when falling rain destroys their flat existence? That’s the question that motivated today’s research study, which looks water striders subjected to artificial rain.
Although the water drops themselves are far heavier than the insects, the water doesn’t strike hard enough to injure the insects. Neither a direct impact nor the forces from a neighboring impact, the researchers found, were enough to pose a problem for the water strider’s exoskeleton. Instead, they’re more likely to get flung or submerged, as follows:
The initial impact of a raindrop creates a large crater. Depending on the position of the insect relative to the point of impact, this may fling the insect away or pull it down into the cavity. When the drop hits, it creates a big crater in the water’s surface. Insects to the outside of the splash get flung outward, while those closer to the point of impact ride the crater wall downward. As the crater collapses, it forms a thick jet that pushes nearby water striders up with it.
As the initial cavity collapses, it creates a large jet that can push the strider into the air. As that initial jet collapses, it forms a second crater, which — being smaller and narrower — collapses much faster than the first one. That action, researchers found, often submerges a water strider caught in the crater.
The first jet’s collapse creates a second crater, and it’s this one that tends to trap and submerge the water strider underwater. Fortunately for the insect, their water-repellent nature means they’re covered in a thin bubble of air that lets them survive several minutes underwater. That’s time enough for the water strider to rescue itself. (Image credit: top – H. Wang, animations – D. Watson et al.; research credit: D. Watson et al.; via APS Physics)
That Drain Life
No matter your cleaning habits, it’s possible to get some unexpected roommates. This variety is the drain fly, a species well-adapted to the moist environment of our pipes. As larvae, they slither and squirm in the biofilms that form from the hair, saliva, and food that make their way down our drains. Being fully immersed is no problem for them, since they carry their own air bubble like a mini scuba tank. In adulthood, these tiny flies are incredibly hairy, all the better to escape from water. All those little hairs trap air near the fly, making it hydrophobic so that water just slides off. It takes a serious dowsing to immerse them enough to drown. (Image and video credit: Deep Look)
Spreading the Word
Just as prairie dogs bark to warn the colony of danger, many plants can signal their neighbors when they’re under attack. This thale cress releases calcium when caterpillars eat it; neighboring plants pick up the chemical signal and pass it along. To better understand how the signal gets passed, researchers genetically modified this plant to fluoresce when extra calcium is on the move. It’s incredible to watch the flow from one side of a leaf to another. (Image and research credit: Y. Aratani et al.; via Colossal)
