Thursday, June 8, 2017

Nature's Earlt Warning

Dr. Abe V. Rotor

Animals can predict earthquake

Horses, reptiles, fowls and other animals perceive the minute tremors preceding a major shock. In explaining the principle of a tectonic earthquake, imagine a stick bent slowly to form an arch. As pressure continues to build up, minute fibers and strands begin to snap (tremors) until the stick suddenly breaks into two (shock). Our senses are not as sensitive as those of animals in perceiving such initial signal.

Dragonflies hover before a rain.

High relative humidity accompanies warm weather. Small insects are disturbed in their natural habitats and feeding. With their sensitive antennae they pick up the signal, which tells them to pack up and leave. Rain is usually preceded with high humidity and air temperature. This steamy condition progressively builds up into rain, and as the process continues, the ancient gene in these insects begins to work, as it has always been with their ancestors thousands, if not millions of years ago. Thus midges, hoppers, gnats, flies, and other insects flee to safer grounds on the instruction of this gene. It is during this mass evacuation that hordes of low flying dragonflies have their fill, snatching the helpless preys in mid-air.

Fruit laden kapok means poor harvest

When you see plenty of dangling pods of cotton tree or kapok (Ceiba pentandra L), expect poor rice harvest. Kapok is sensitive to water stress. It does not have deep penetrating roots. Instead it has large spreading roots that depend largely on shallow water source. To compensate for lack of water in summer, the tree stores a lot water in its fleshy trunk and branches like how cactus does while water supply lasts. When the stored water is not sufficient to tide up with the long, hot summer months, a triggering mechanism controlled by hormone stimulates the tree’s physiology. The plant bears flowers and ultimately fruits and seeds, a trait universal to any organism facing stress. This is the key to the perpetuation of the species. In short, Nature has provided a means with which an organism’s ultimate biological function to reproduce is carried on. And the more progeny it produces the more is the chance of the species to continue on.

Stress stimulates reproduction. Wounding (cutting the bark, staggered and at close intervals with bolo) the trunk of a mango that refuses to bear fruits, stimulates it to flower. This is true with other orchard trees. Pruning follows the same principle. Botanists explain the phenomenon this way. “Food”, which is otherwise used for vegetative growth will now be diverted to the development of flowers and fruits. But geneticists have a further explanation. Again, a gene that controls this balance responds favorably to saving the species – even with the risk that the parent may die. In many cases this is also true in the animal kingdom, and among protists.

When earthworms crawl out of their holes, a flood is coming.

It was early morning at Kenting Park in southern Taiwan, my student and thesis advisee, Anthony Cheng, and I saw earthworms, bigger than the size of pencil crawling away from their burrows. He looked up the sky. “Is it going to rain?” I asked noting the heavy overcast. “No, but we haven’t the monsoon yet.” It was already August.
Image result for earthwormsBy the way, earthworms are subterranean, eating on decomposing leaves, and converting them into humus, a very rich soil, called casting. That is why farmers and gardeners call the earthworm as Nature’s fertilizer factory. Tons and tons of castings are brought out of their burrows and deposited on the ground in small mounds.

Why do earthworms abandon their burrows before an impending heavy rain or flood? Earthworms drown when water fill their burrows, so that their recourse is to move out to higher grounds. Nature has equipped them with sensitive hairs around their body connected with a neural system that guides them find rich deposits of organic matter and water. In summer earthworms penetrate deep and wide. Then in monsoon as ground water rises, they burrow in higher areas, this time to keep away from too much water. Making use of this evolutionary tool - a kind of Noah’s sixth sense, so to speak - earthworms avoid getting entombed in their very burrows.

Swarming of winged termites confirms the rainy season (habagat)has finally arrived.

They come by the armies, careless and suicidal, attracted by light and ending in a basin of water. That is how we catch gamu-gamu, or simut-simut in Ilocano, which we feed to chicken, or sauté into a rare delicacy. Where did the swarm come from? And why only at a specific time of the year?

Termites belong to a very ancient Order of insects, Isoptera, which means “same wings”. Yet when we examine termites after digging their nest called anthill (punso’), we find them wingless, naked, and small, except their large heads, and mandibles especially in the case of the soldiers. In the royal chamber lies a queen, enormously large, the size of the index finger. Her job throughout her long life is to lay thousands of eggs everyday and keep the colony intact through a scent she produces called pheromone.

It is the end of summer. After the first heavy rain usually in May, the anthill becomes extraordinarily busy. Inside, the once sterile males and females – formerly soldiers and workers - awaken to the dictates of hormones. They develop strong wings, and with their bodies filled up with fats, they are ready for the once-in-a-lifetime adventure - swarming. The nocturnal swarm soon takes place, and moves as one huge army guided by light – celestial or neon – before it splits into congregans, allowing intermingling with members from other anthills. Now the much-awaited nuptial flight begins. For hours the winged termites circle around lights, very much like the proverbial moth in Rizal’s writings. In the process, individuals, which survive the frenzy and onslaught by predators, find their mates, move together to a potential place, and finding it suitable to start a new colony, soon lose their wings. Here they live together for a very long time. Termites are the longest living insects, surpassing the life of the 17-year old locust or cicada.
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May or June Beetle heralds the coming of the rainy season.

We call it salagubang, scientifically Leucopholis irrorata, a destructive pest of many field crops. Its larva, a white grub, which feeds on roots, remains in the ground until the first strong rain comes. Then it comes out as beetle. If the monsoon is early they come out in May, otherwise they are seen coming out in June.

But this year I have noticed that the emergence of this beetle was as early as in April. Why is this so? It is because of the unusual rainfall pattern this year. Practically there was no summer as you have probably experienced. It means then that the insect responds to meteorological signals that govern its biological clock. How this phenomenon works is not well understood, but definitely, it is a product of a long evolutionary process that enabled the species to survive up to this day.

Co-evolution with plants on which it thrives in both larval and adult stages gradually developed through time into a dynamic pattern, that while the host plants are at the receiving end, the insect’s feeding habit and life cycle are attuned to a tolerable level. Thus we usually find the insect in areas where this natural relationship exists. If you find the salagubang, and its relative, the salaguinto, in May, farmers are likely to start plowing their fields soon. Farmers are glad to see the beetle come out in May, or as early as April. It is because they can plant earlier which allows for a second crop of vegetables or legumes – or another rice crop.

Related imageCicada sings for rain.

When you hear the shrilling song of cicada (kuliglig), it means the rains have finally arrived. From here we expect the rains to intensify throughout the southeast monsoon or habagat then tapers off in October. The cicada spends its immature or nymph stage in the ground feeding on roots of plants. There are species that complete their life cycle in one year (annual cicada which is most common), two years, and seventeen years (often called seventeen-year old locust). Whatever is the species, the emergence of cicada is at the onset of the rainy season, usually in April or May in most part of the country.

Rain softens the soil and signals the full-grown nymph to get out of its cell. It then climbs to the nearest tree and at some distance from the ground, it metamorphoses into an adult. It is the male cicada that “sings”, which is actually a continuous rapid high-pitched sound - tick-tack-tick-tack… produced by a pair of drums attached on its abdomen. Imagine the lid of a tin can pressed and released in rapid succession. On the other hand, the female cicada is totally mute and her response to a get near a Romeo whose song pleases her.

 means that a strong rain, if not a typhoon, is coming. Cockroaches come out of their abode and seek for shelter.

The biological clock of these creatures responds to invisible signals, which comprise decreased atmospheric pressure, high relative humidity and air temperature. Their sensitive antennae and tactile hairs covering their body pick these up these changes of the environment. Thus we find ants in exodus, they move as a colony carrying their eggs and young indoors. Cockroaches become unusually active, flying about in frenzy, in search for a new place. There is a common message, that is, to escape to safer ground, an archetype ingrained in their genes passed on to them by their ancestors through evolution.

Mosquitoes bite more aggressively before rain.

True. Like any organism preparing for reproduction, the female mosquito must be able to obtain blood to enhance egg fertility. Failure to do so may cause eggs to become sterile, a finding which can be applied in controlling this ferocious vampire which has caused human death more than all casualties of wars combined. Note: Only the female mosquito feeds on blood, the male depends on plant sap and exudates.

The kingfisher (salaksak) is an emissary of death.

The kingfisher’s throaty voice is a call of death, so the old folks say. Well, when ponds and rivers dry up because of drought, this fish eater will scour for alternative food outside its niche, poaching around farms and homes.

When the leaves of Samanea acacia fold it’s time to go home - before it gets dark.

It is time to fetch the carabao from the pasture and to start walking home before it gets dark. The fowls prepare to roast in their tree abode. The stew leaves a trail, as the western sky dims in the setting sun. By now the leaves of acacia (Samanea saman) have completely folded toward each other at the midrib, and the base of the midrib itself is bent on its attachment. This is also true with the leaves of sampaloc, ipil-ipil, kakawate - and more so with makahiya.

These plants, among others, belong to the legume family and are equipped with a special organ – pulvinus – that controls the erection and folding of the leaves. The principle is like a balloon. When turgid the leaves are erect; when flaccid, the leaves fold. The pulvinus is controlled by osmosis, that is, the intake and release of water in the cells.

Reference of time among old folks is built through observation of the natural environment and a lifestyle where the amenities of modern living are absent. This triggers our biological clock, and while it may not be accurate, brings people to a natural sense of time and quaint living.

Nature’s mysterious ways are discreet and take place when all is still and quiet. But anyone of us who stirs to the nuptial flight of winged termites and ants, to the restlessness of catfish before an impending earthquake, the dangling of numerous pods of kapok which signals the coming of El Nino, earthworms abandoning their underground homes to escape flood, the emergence of “April beetle”, - is indeed endowed with a special intelligence – naturalism. If however, no bird sings when the spring has come, either we have slept too long, or we have failed to prepare for its coming.
Acknowledgement: Internet photos,except that of kapok tree.

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