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Sunday, 3 April 2016


(Image source: www.flickr.com)

One day, I visited my nephews and I found a water pistol among their toys. I was in the mood to play so I filled it up with water and went outside to test my hit man skill. I couldn’t find any challenging target so I kept pointing and squirting out the liquid and just when I was almost getting bored, I found a live and moving target—the dragonfly.  As a patient man, I waited for it to perch on the surface of the fence it was hovering over. Finally, it did. Like Agent 47, I aimed my ‘9mm’ and fired. Guess what? I missed! Damn! The agent was better. After multiple attempts, I mastered the fluid’s trajectory and the degree of pressure to apply on the trigger with respect to distance from the target. I hit the fly and it moved to another spot. I followed it round and fun began. A little voice inside me was like, “dude, this thing could turn tiger and sting the heck out of you” but I ignored and played on, though with caution.

Now, let’s keep my childishness aside, though it’s necessary to keep the mind flexible and young. Let’s get down to business. We’ve introduced a new category into our blog; Knowledge Box. Go to the homepage of this blog and check out this category.  We’ve found out there’s a need to enlighten our readers on some facts to keep their intellectual archive loaded on certain topics people have vague knowledge on. As they say, knowledge is power. Who knows who’ll ask you a question that would leave you mute, probably like the other time? Who knows when your friends may bring up a strange topic and start to debate on? But you, already enlightened on the topic will have facts to educate them.
Today, we wonna talk about a special creature—the dragonfly. Let’s find out a little about this fly under these subtopics.

Dragonflies are ancient insects
Long before the dinosaurs walked the Earth, dragonflies took to the air.
If we could transport ourselves back 250 million years, we would immediately recognize the familiar sight of dragonflies flying in pursuit of prey. Griffenflies, the gigantic precursors of our modern dragonflies, took flight in the Carboniferous period over 300 million years ago. Now that’s some scary shit there. Who’d wonna travel back 250 million years? Well, maybe I could, just to take a selfie with a Griffenfly and come back to post on Facebook.

As nymphs, dragonflies live in the water
There's a good reason why you see dragonflies around ponds and lakes – they're aquatic!
Female dragonflies deposit their eggs on the water's surface, or in some cases, insert them into aquatic plants or mosses. Once hatched, the nymph (or naiad, in this case) spends its time hunting other aquatic invertebrates. Larger species will even eat the occasional small fish or tadpole. After molting 9-17 times, the dragonfly will finally be ready for adulthood, and the nymph will crawl out of the water to shed its final nymphal skin. You may ask yourself, “what’s nymph?” Well, it’s the larva stage of some insects like grasshoppers and dragonflies that do not undergo complete metamorphoses. They grow from this stage directly into adults without passing through the pupa stage. And the molting part; molting is just a biological process of shedding off the old skin, like snakes do and some reptiles. I feel like molting off this mark on my skin.

A dragonfly nymph breathes through its anus
The dragonfly nymph's gills, oddly, are inside its rectum. That's right, it breathes with its butt. The dragonfly nymph will pull water into its anus, where gas exchange occurs.
When the dragonfly expels the water from its rear, it propels the nymph forward, providing the added benefit of locomotion. Eeww! That’s sensitive, but on a second thought, I secretly wished humans breathe that way. Tell me how we’d have gays. No one would risk suffocation.

Up to 90% of young dragonfly adults get eaten.
When the nymph is finally ready for adulthood, it crawls out of the water onto a rock or plant stem and molts one last time. It takes up to an hour for the adult to expand its body.
This newly emerged dragonfly, referred to as a teneral adult, is soft-bodied and pale, and highly vulnerable to predators. For the first few days, until its body hardens fully, it is a weak flier. Teneral adults are ripe for the picking, and birds and other predators consume a significant number of young dragonflies in the first few days after emergence. That’s sad; I guess that’s how the food cycle works. Bird eats fly and gets eaten by …. And so on.

Dragonflies have excellent vision
Relative to other insects, dragonfly vision is extraordinarily good. The head consists almost entirely of two huge compound eyes, which gives the dragonfly nearly 360° vision. Each compound eye contains as many as 30,000 lenses, or ommatidia. A dragonfly uses about 80% of its brain to process all this visual information. They can see a wider spectrum of colors than humans. This remarkable vision helps them detect the movement of other insects and avoid collisions in flight. Wow! That’s superb! If I had such compound eyes, I could have probably seen the signs that my girl would leave me. Nah, I’m kidding. No girl walks away from Prince Charming.

Dragonflies are masters of flight
Dragonflies can move each of their four wings independently. In addition to flapping each wing up and down, they can rotate their wings forward and back on an axis. This flexibility enables them to put on an aerial show like no other insect. Dragonflies can move straight up or down, fly backwards, stop and hover, and make hairpin turns, at full speed or in slow motion. A dragonfly can fly forward at a speed of 100 body lengths per second, or up to 30 miles per hour. Scientists at Harvard University used high-speed cameras to study dragonfly flight. They photographed dragonflies taking flight, catching prey, and returning to a perch, all within a time span of just 1-1.5 seconds. Oboy! And you thought you were fast. I think the government should organize a contest for trained dragonflies so they’d do the aerial show like military jets do on Armed Forces Day (if I’m not mistaken). 

Male dragonflies exhibit aggression toward other males
Competition for females is fierce and male dragonflies will aggressively fend off other suitors. In some species, males will claim and defend a territory against intrusion from other males. Skimmers, clubtails, and petaltails scout out prime egg laying locations around the local pond. Should a competitor fly into his chosen habitat, the defending male will chase him off. Other kinds of dragonflies don't defend specific territories, but will still behave aggressively to other males that cross their flight paths or dare to approach their perches. Look at that! I think they learnt that from humans. Things we do for the ever dependent females. I wonder if their females also demand money for make ups and gold jewelries. Smh.

The male dragonfly has secondary sex organs
In nearly all insects, the male sex organs are located at the tip of the abdomen. Not so in male dragonflies. His copulatory organ is on the underside of his abdomen, up around the second and third segments. His sperm, however, is stored in an opening of his ninth abdominal segment. Before mating, he has to fold his abdomen and transfer his sperm to his penis. Hmm…let me not talk about this. I can only imagine the size.

Some dragonflies migrate
A number of dragonfly species are known to migrate, either singly or en masse. As with other organisms that migrate, dragonflies relocate to follow or find needed resources or in response to environmental changes like cold weather. Green darners, for example, fly south each fall, moving in sizeable swarms. They migrate north again in the spring. The globe skimmer is one of several species known to develop in temporary freshwater pools. Forced to follow the rains that replenish their breeding sites, the globe skimmer set a new insect world record when a biologist documented its 11,000 mile trip between India and Africa. Wow! What a trip. Welcome to Africa dear. How’re my brown-skinned friends?

Dragonflies are capable of thermoregulation
Like all insects, dragonflies are technically ectotherms (cold-blooded). But that doesn't mean they're at the mercy of Mother Nature to keep them warm or cool. Dragonflies that patrol (fly back and forth, versus those that tend to perch) will fire up their wings, using a rapid whirring movement to warm up their bodies. Perching dragonflies rely on solar energy for warmth, but position their bodies skillfully to maximize the surface area exposed to the sun's rays. Some even use their wings as reflectors, tilting them to direct the solar radiation toward their bodies. Conversely, during hot spells some dragonflies will position their bodies to minimize sun exposure, and use their wings to deflect the sun. That’s creative. I think we engineers have learnt a lot from this wonderful creature and still have some more to learn. The solar deflection sounds intelligent.

From these, you can appreciate the wonders of nature in the body of this slim fly with four wings. Yes, I almost forgot, they don't sting! That means more shooting next time! Isn’t our Creator wonderful? 

References: www.insects.about.com, Encarta Dictionary 2009

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