The mysterious signals of nature
The signals sent in the natural world may seem strange to us, but are actually very clever means of communication.
“I just couldn’t get through to you, the signal was too weak.” This remark is oft heard today when our cell phones fail to pick up the satellite signals. But in the dense jungles, the male Emperor moth uses its broad feathery antennae to sniff out the pheromones sent out by the females from as far as eight to eleven kilometres away. In an experiment, a female Emperor moth was placed in a cage in the woods. Within three hours, she attracted a hundred desperate males from the surrounding countryside.
Certain Acacia trees are known to send out signals to others of their kind within fifty yards to warn them of browsers. Imagine a herd of cows grazing upon these Acacias. After the animals have chomped on them for some time, the leaves suddenly begin to taste unpleasant as they have developed poison in them. The cows then move on to the next group of Acacias. But these trees have already been forewarned by a signal sent to them from the earlier trees and so they have equipped themselves with poison, too. The first bunch of trees actually sent out ethylene gas to warn the second bunch. It is only when the cows walk a fair distance, more than fifty yards away, that they come upon a new lot of trees that are too far to receive this signal and have thus, not accumulated any poison in them as yet.
It is a known fact that wingless female glow worms send light signals to the winged males of their species, who are known as fireflies. Each species of these insects have their own signature signals, a kind of Morse code that flashes on and off in a specific pattern so that the males can find their female mates. But sometimes, hungry females deliberately mimic the signals of other species and when the hapless males of the other species trustingly arrive, they are simply gobbled up!
In the United States, there is a species of cicada, which spends its early life underground as a nymph, sucking the sap of roots. Here they remain for seventeen years and at the end of this long period, they seem to receive a mysterious signal which tells them it’s time to come out. Choosing a late spring day, when the ground temperature is about 17 degrees Celsius, millions of them emerge from the ground, en masse. The box-headed insects with bulging red eyes climb onto branches and moult for the last time, turning into winged adults. The males begin singing in chorus, as if performing a deafening rock concert, calling out to their female counterparts.
Lakhota Lake in Jamnagar is famous for the spectacular aerial display – called murmuration – performed by the Rosy Starlings. Just around sunset, thousands of these birds gather in the orange evening sky, like one big thundercloud. In unison, they fly ever so gracefully and synchronously, swirling and swaying in different formations – now a ball, then a fish, then a pendulum… It is a great treat to watch! How they signal to each other their next spontaneous move, their next wing beat, simply bowls us over.
Indeed, there are a variety of intriguing signals amongst nature’s creations; one could go on and on. And what is most commendable is that they always work, unlike the signals we humans depend on.