There are many solutions that claim to repel flying insects; some even work.
For instance, there are chemicals - stuff you put on your skin, stuff you burn like incense - at least this makes sense: we can see how some smelly material may offend the insect’s finer sensibilities. Then there are hi-tech solutions, like the electronic gadgets that supposedly emit a hypersonic sound that mosquitoes can’t stand. We once tried this out - my son sneaked up on a mosquito standing on a wall and turned the gizmo on right next to the critter’s ear (or whatever they have). The insect didn’t even deign to move an antenna; maybe it was deaf (or maybe we were sold the electronic equivalent of snake oil).
But the most amazing device is one I snapped in a restaurant today: a nylon bag filled with water, hanging from the rafters (I’ve also seen them hanging from tree branches occasionally). And this traditional system is in use not only in Israel - as I discovered in Google, the same method is used in the US, Mexico and elsewhere: so it’s really globally known.
I asked the waiter why a water bag will drive flies away, and he said with great certainty that the fly sees its own enlarged reflection in the water and it scares it away. I heard this explanation before; presumably the fly thinks it just met a bigger, meaner fly, and decides that retreat would be prudent.
I have no idea whether anyone confirmed this theory (any input on this is welcome), but whether the explanation is correct or not, you have to admit this is one solution that is perfectly acceptable from all angles: environmentally friendly, harmless to humans, humane even to the flies, and as cheap as it gets.
Speciation, in evolutionary biology, is the splitting of a species into two different sub-species that cannot interbreed; it is one of the engines powering evolution. One mechanism responsible for this is the appearance of a physical barrier that cuts part of the species off from the rest, as when tectonic activity creates an insurmountable rift or mountain range, or an island breaks off from the mainland. The creatures on either side of the barrier evolve independently, resulting in such wonders as the dwarf elephants that used to exist on mediterranean islands, or the diverse finch species of the Galapagos.
During my recent visit to Berlin I was amused to see the same phenomenon, of sorts, happen to man-made objects - namely, pedestrian traffic lights.
Pedestrian crossing Walk/Don’t walk signals vary between countries, but in each country they usually have one standard design. In Europe they usually follow the European standard of a red standing man and a green walking man.
Now this is also the case in Berlin, except that there they have two designs. In West Berlin, the little men are skinny and utilitarian; but in East Berlin they are stylized, chubby and humorous: the famous Ampelmännchen.
The Ampelmann design was developed in the GDR in 1961, and was used in East Germany while the barrier of the Iron Curtain prevented design standardization with the West. When the Berlin Wall became history, the citizens of that fascinating city had two different signal types; for a while you could tell which part of town you’re in by observing the one in use.
And when a barrier comes down and the two species mix again, it is possible for one to wipe out the other. In Berlin, there were plans to replace the Ampelmann with the EU standard of the skinny, businesslike version. Fortunately this planned extinction of the eastern variety met with a public outcry, and now the funny man in the hat is a protected species; in fact I heard they plan to replace the western version with Ampelmännchen, since they’ve become a kind of city mascot. In one pedestrian crossing I even saw the two little men - East and West - eyeing each other uneasily across the street…
The wonders of the natural world are many, and the living body includes countless amazing features (and, admittedly, some not-so-amazing ones as well). Today I give due homage to a piece of truly elegant design: the perfect match of the outer ear to the iPod’s earphones!
The earphones’ convenient usage stems from the presence of those details of ear anatomy that form a perfect keyhole structure to hold the earbud in place just against the opening of the ear canal. The structure echoes (after a 180 degree turn) that seen on the backs of many wall-mounted household objects, like the fan seen in the photo below.
In case you wondered, the small folds in the outer ear’s convolutions that make this possible are called the Tragus and Anti-Tragus, as seen in this detailed illustration from Gray’s Anatomy. They hold the earphone’s round body in a snug fit against the suitably sized Concha.
We humans may not have the most impressive ears (just ask a bat, or a rabbit, or an elephant) but we certainly come pre-customized to hear our favorite music on the go!
