A Glimpse into the World of Insect (A Lesson in Entomology)

Dr Abe V Rotor
Living with Nature School on Blog 

Lesson: Entomology - and other sciences - can be made more interesting through popular writing, translating the technical nature of science to the level of undertanding, and entertainment, particularly among children. The humanities treatment of this article, enriched by painting and photography, enhances general readership and appreciation of the subject. 

Garden - Haven of Insects
La Union Botanical Garden, Cadaclan, San Fernando, LU. On-the-spot painting by Abe V Rotor. Courtesy of Dr. Romualdo M del Rosario, Project Director. 

With increasing population, traffic and commerce all around a community, there is one place, a garden, that offers a wildlife sanctuary, specially insects. Here they live freely in the trees and shrubs, on annuals, inside the greenhouses, around the ponds, in loamy soil, and in the shade of buildings, and even visit homes seeking a suitable abode.

I have the feeling that of all animals, insects are the most adapted to the varied aspects of human activities, from the sound of hurrying feet to soft echoes of prayer and hymns – and loud music. When there are humans around, insects feed on morsels, paper and crayons, drink on fruit juices and beer. They aestivate in flower pots and boxes to tide with the harsh summer months. Or hibernate when the cold Siberian High comes. I think Pavlov’s conditioned learning works with insects as well.

Interestingly, as an entomologist, I have been monitoring the insects in some gardens, listing down a good number of species that include those not readily found elsewhere. These include a giant click beetle, a rhinoceros beetle with horns resembling a triceratops, Ficus pollinating wasp, leaf-curling thrips of ikmo, long horned grasshoppers, sulfur and Papilio butterflies.

Well, it is a fact that there is no escape from insects - good or bad ones. In terms of species, there are 7 insects out of 10 animal’s organisms of earth. Insects comprise 800,000 kinds and scientists estimate that their kin-lobster shrimps, spiders, ticks, centipedes, millipedes and scorpions if these were to be added, the phylum to which they all belongs, Phylum Arthropoda, would comprise 80 percent of all animals organisms. To compare, plants make up only one-half million species.
Daddy-long-legs, relative of the mosquito, quakes continuously when at rest by swaying its body back and forth in all directions, causing blurred view to a would-be attacker, and mesmerizing a potential prey. In the open, such optical illustion is enhanced by the shadow of the moving organism. Note the hind pair of wings reduced into halteres or balancer, characteristic of Dipterans. There is another kind of daddy-long-legs which belongs to Arachnida.

Antlion's traps. The predatory larva of this Neuropteran (Dendroleon obsoletum) lies buried at the bottom of the pit waiting for an unwary ant to fall and become its meal.

What secrets have insects in dominating the animal world, and surpassing the geologic history of dinosaurs, fishes, mammals and even some mollusks?

Well look at the ants, termites, and bees, the so-called social insects. Their caste system is so intact and strict that is was long regarded as a model of man’s quest for a perfect society. It inspired the building of highly autocratic empires like Egyptian and Roman Empires, and the monarchial Aztecs, Inca and Mayan civilizations.

Take the case of the butterflies and moths. Their active time is not only well defined - diurnal or nocturnal, but their food is highly specific to a plant or group of plants and their parts. Their life cycles allow either accelerated or suspended metamorphosis depending on the prevailing conditions of the environment, a feat no other animal can do more efficiently.

One time my students gathered around me by the ponds. There I explained to them the bizarre life of the dragonfly, once a contemporary of the dinosaur. Its young called nymph is a fearful hunter in water as the adult is in air. Apparently this is the reason on how it got its legendary name. I showed them the weapons of insects: the preying mantis carries a pair of ax-and-vise, a bee brandishes a poisonous dagger, while a tussock moth is cloaked with stinging barbs, a stink bug sprays corrosive acid on eyes or skin. The weevil has an auger snout, the grasshopper grins with shear-like mandibles, and the mosquito tucks in a long, contaminated needle.

We examined a beetle. Our thought brought us to the medieval age. A knight in full battle gear! Chitin, which makes up its armor called exoskeleton, has not been successfully copied in the laboratory. So with the light of the firefly, the most efficient of all lights on earth.

Wait until you hear this! Aphids, scale insects and some dipterans, are capable of paedogenesis, that is, the ability of immature insects to produce young even before reaching maturity!

Numbers, numbers, numbers. This is the secret of survival and dominance in the biological world. King Solomon is wise indeed in halting his army so that another army - an army of ants can pass. Killer ants and killer bees destroy anything that impedes their passage, including livestock - and human.

Invisibility is another key to insect survival and dominance. Have you examined the inside of leaf galls in santol, Ficus and ikmo? Well, you need a microscope to see the culprit - thrips or red mites. I demonstrated to my students how insects, being very small, can ride on the wind and current, find easy shelter, and are less subjected to injury when they fall. Also, insects require relatively less energy than bigger organisms do. All of these contribute to their persistence and worldwide distribution. Insects surely are among the ultimate survivors of a disaster.

In an article I wrote, A Night of Music in a Garden I described Nature’s musicians, the cricket and the katydid. While their sounds are music to many of us they are totally coded sounds similar to our communications. Cicadas, beetles, grasshopper, have their own “languages”, and in the case of termites and bees, their language is in the form of chemical signals known as pheromones. It is from them that we are learning pheromones in humans.

A Walking Stick, a perfect example of mimicry.

Without insects, we are certain to miss our sweetest sugar which is honey, the finest fabric which is silk, the mysterious fig (Smyrna fig) which is an exotic fruit. We would be having less and less of luscious fruits, succulent vegetables, the reddest dye, unique flavor in cheese, and most likely we will not have enough food to eat because insects are the chief pollinators, and main food of fishes and other animals. They are major links in the food chains and food webs, the columns of a biological Parthenon.

Without insects, the earth would be littered with dead bodies of plants and animals. Insects are the co-workers of decomposition with bacteria and fungi as they prepare for the life of the next generation by converting dead tissues into organic materials and ultimately into their inorganic forms. Together they help bridge the living and the non-living world.

A garden without bees and butterflies mirrors a scenario of the biblical fall. And if the other creatures in that garden strayed away from its beautiful premises as our first forebears began their wandering, they too, must have learned the true values of life, which they share to us today.

Beautiful is the verse from A Gnat and a Bee, an Aesop fables. To wit:

“The wretch who works not for his daily bread,
Sighs and complains, but ought not to be fed.
Think, when you see stout beggars on their stand,
The lazy are the locusts of the land.”

In The Ant and the Grasshopper, Aesop, acting like a father with a rod in hand, warns. He was referring to the happy-go-lucky grasshopper.

“Oh now, while health and vigour still remain,
Toil, toil, my lad, to purchase honest again!
Shun idleness! Shun pleasure’s tempting snare!
A youth of rebels breeds age of care.”

Ecologically insects are the barometer of the kind of environment we live in. A pristine environment attracts beneficial insects, while a spoilt one breeds pests and diseases.
Ficus pseudopalma and its exclusive wasp pollinator, a classical example of co-evolution. Only this species of wasp can pollinate and subsequently fertilize the introverted flower of this fig plant. Wasp is magnified 20x under a stereo microscope.

I have yet to see a firefly in a city garden. I remember an article in Renato Constantino’s series of publications, Issues Without Tears. Its title is, You don’t See Fireflies Anymore, a prophesy of doom, a second to Rachel Carson’s Silent Spring.

Maybe. But I have not lost hope. Someday, a flicker in the night may yet come from a firefly and not from a car or cigarette - if only others will share with me the same optimism.
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