I'm amazed and delighted to have observed the amazing fluidity of this butterfly in flight.
That got me thinking about how a butterfly's wings can support it in flight and, why, does a butterfly seem to fly so erratically yet is actually very purposeful and directional?
To fly, a butterfly must obtain warmth from the sun by basking and exposing its thorax, where the muscles attach, or by creating warmth with rapid movements (much like humans warm up before exercising). (REF)
The wings of the butterfly are made of hard tubes covered with thin tissue. The wings are covered with scales, which are like a fine dust.
The scales form bright patterns, sometimes with a hidden ultraviolet pattern to attract mates. The bright colours also act as a deterrent to predators eating them. The scales may also form patterns that help the butterflies to blend into their background to escape predators. (REF)
During flight, the forewing and hindwing are held together and function as one wing. The coupling mechanism differs in different species. In most butterflies, a lobe on the hindwing presses against the forewing.
It’s not just poetic alliteration that makes the pat phrase “a butterfly fluttered by” so appropriate. The insects, although not always that speedy, often take a flight path that involves so many erratic dips and turns that they almost look out of control. But it’s not because they can’t do any better: Such unpredictable flight is how butterflies evade birds and other predators. However, most butterflies are brightly colored, which would seem to counter their evasiveness by making them easier to spot and track. “The question always bothered me,” says Thomas Eisner, a biologist at Cornell University. “Why are butterflies flaunting their visibility?” As Eisner and Benjamin Jantzen, a doctoral candidate now at Carnegie Mellon University, report in the October 28 issue of theProceedings of the National Academy of Sciences, a butterfly’s ability to evade and its blatant pigmentation may go hand in hand.
The first step was to find out what physical feature of butterflies allows them to move so erratically. It’s been known for about a century that the front wings in butterflies are the ones driven by the insect’s muscles; the hind wings are passively coupled to the front ones. Eisner decided to investigate just what the back wings were doing by trimming them away bit by bit. To his surprise, he found that if he removed the entire hind wing, the insects had no problem flying. Indeed, when Eisner went on to test an extensive list of butterfly and moth species, he found that without exception they were all capable of sustained flight with only their front wings. “It is pretty startling that they’re that overendowed with lifting surface,” says Jantzen.
Read more here.........What's All The Flap About?