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Monday, February 6, 2023

the wings of a butterfly !!

 The first thing that attracted me was its wings – so colourful with a great pattern !! – the wings   are made of very thin layers of a hardened protein called chitin. (human  hair and nails are also made out of this protein.) On top of these chitin layers are thousands of tiny scales that serve several purposes, which may vary for different species of butterflies. 

I've watched you now a full half-hour;

Self-poised upon that yellow flower

And, little Butterfly! indeed

I know not if you sleep or feed.

How motionless!--not frozen seas


Butterflies (Rhopalocera) are insects that have large, often brightly coloured wings, and a conspicuous, fluttering flight. The group comprises the superfamilies Hedyloidea (moth-butterflies in the Americas) and Papilionoidea. Butterfly fossils date to the Paleocene, about 56 million years ago. 

Butterflies have a four-stage life cycle, they undergo complete metamorphosis. Winged adults lay eggs on the food plant on which their larvae, known as caterpillars, will feed. The caterpillars grow, sometimes very rapidly, and when fully developed, pupate in a chrysalis. When metamorphosis is complete, the pupal skin splits, the adult insect climbs out, and after its wings have expanded and dried, it flies off. 

We often admire butterflies for the splendid colours on their wings, and  a dark background can make them shine even brighter. Just like strong colours in nature are often the result of diffraction from microstructures rather than pigmentation, the near-perfect absorption we perceive as black can have a similar origin.   

A butterfly has four wings, two forewings and two hindwings. They are attached to the second and third thoracic segments (the meso- and meta-thorax). Strong muscles in the thorax move the wings up and down in a figure-eight pattern during flight. When the fully-grown adult butterfly emerges from its pupa, its delicate wings are crinkled, wet, and uninflated. The butterfly hangs upside-down and pumps blood into the wings to inflate them. It must then wait for the wings to dry before it can fly. When the fragile wings fray or are torn, they do not repair themselves. 

Butterfly wings are made of two chitonous layers (membranes) that are nourished and supported by tubular veins. The veins also function in oxygen exchange ("breathing"). Covering the wings are thousands of colorful scales, together with many hairs (setae).  The variations in hues and patterns on their wings are not just for show but perform crucial communication functions. The patterns on the wings can help protect butterflies from predators through camouflage, or warn predators that the butterfly’s body is toxic, or help attract potential mates. A major feature of these wing canvases is that they have two sides and they can contain different messages on each side. In general, butterflies use the upper surfaces of their wings to seduce the opposite sex !! 

Butterflies' lives are all about flight. Their vibrant wings are the largest, most visible parts of their bodies, and they spend much of their time in the air. Flying takes a lot of energy, and to get this energy, butterflies drink the nectar from flowers, which require the power of flight to reach. Even when resting, butterflies are often preparing for flight by keeping their wing muscles warm enough to move. 

The most important thing – never touch them, their wings ! – you are not caressing them but could damage them permanently.  When you touch a butterfly's wing, enough scales come off to negatively affect its heat absorption, it could conceivably lead to its death.   The  scales --   rub off easily -- partly to allow the butterfly to escape from predators in a tight situation. Unfortunately, that escape could ultimately lead to the same outcome as getting caught in the first place. 

The lyrics at the start are from a poem that we read in our School days – ‘Butterfly by Wordsworth’.  William Wordsworth (1770 –   1850) was an English Romantic poet who, with Samuel Taylor Coleridge, helped to launch the Romantic Age in English literature with their joint publication Lyrical Ballads.  Wordsworth's magnum opus is generally considered to be The Prelude, a semi-autobiographical poem of his early years that he revised and expanded a number of times. It was posthumously titled and published by his wife in the year of his death, before which it was generally known as "the poem to Coleridge". 

Interesting !
With regards – S. Sampathkumar

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