A foggy day and cold as hell. Got 8 flights delayed and 1 flight cancelled.
Thursday, December 23, 2010
7:40 AM@December 24 2010
A foggy day and cold as hell. Got 8 flights delayed and 1 flight cancelled.
Sunday, December 12, 2010
Thursday, December 9, 2010
Tuesday, December 7, 2010
7:40 AM@December 8, 2010
Cold Mornings in Bangalore. Was curious to know how the mornings changed. So decided to post pics of mornings everyday. Currently reading Prisoner of Tehran by Marina Nemat.
Monday, July 5, 2010
Wingless Insects
Flight among insects are varied. Some fly, some do not and some have forgotten it. There are numerous different groups of insects who have lost their wings or greatly reduced them. Unlike primitively wingless insects such as silverfish, fleas and lice have lost the wings their ancestors once had.
From left to right: silverfish, flea and lice
An additional reason for winglessness is an evolutionary defense mechanism of assuming a protective resemblance to ants, either (or both) to fool the ants or to fool would-be predators who might otherwise pick them out from among the less palatable and better protected ants.
Female gypsy moths have underdeveloped wing muscles and don't fly. They don't need to, for the males fly to them, attracted by a chemical lure which they can detect at astounding dilutions. If the females were to move as well as the males, the system probably wouldn't work, for by the time the male had flown up the slowly drifting chemical gradient, its source would have moved on.
The female of the dreaded gypsy moth
Unlike most insects, which have four wings, the flies, as their latin name Diptera suggests, have only two. The second pair of wings has become reduced to halteres.
Diptera
The second pair of wings have become reduced to a pair of halteres. These swing about like very high speed Indian clubs, which they resemble, functioning as tiny gyroscopes. We know these halteres are vestigial remains of wings for several reasons
- they occupy exactly the same place in the third segment of the thorax as the flying wing occupies in the second thoracic segment (and the third too in other insects).
- they move in a figure of eight pattern as the wings of flies.
- they have the same embryology as wings and, although they are tiny, if you look at them carefully, especially during development, you can see that they are stunted wings, clearly modified.
- all insect wings have tiny sense organs in the base, which detect twisting and other forces. The sense organs at the base of halteres are very similar.
Halteres on a cranefly
Halteres are what makes between stable and unstable fliers. In any flying machine, there is a trade-off between stability and maneuverability. John Maynard Smith pointed out that animals lose inherent stability in the interests of increased maneuverability, but paying for it in the form of increased instrumentation and computation capability - brain power. The four winged ancestors of flies probably had long abdomens which would make them stable. All four wings would have acted as rudimentary gyroscopes. The ancestors of flies started to move along the stability continuum becoming more maneuverable and less stable as the abdomen got shorter. The hind wings started to shift more towards the gyroscopic function (which they had always performed, in a small way, as wings), becoming smaller, and heavier for their size, while the forewings enlarged to take over more of the flying. There would have been a gradual continuum of change, as the forewings assumed ever more of the burden of aviation, while the hind wings shrank to take over the avionics.
Worker ants have lost their wings, but not the capacity to grow wings. They lost their wings in evolution because they are a nuisance and get in the way underground. Queen ants and male ants have wings and worker ants are females who could have become queens but for environmental reasons (not genetic) failed to become queens. Queen ants use their wings only once, to fly out of the natal nest, find a mate and then settle down to dig a hole for a new nest. As they begin their new life underground the first thing they do is lose their wings, in some cases by literally biting them off.
The female of the dreaded gypsy mothUnlike most insects, which have four wings, the flies, as their latin name Diptera suggests, have only two. The second pair of wings has become reduced to halteres.
DipteraThe second pair of wings have become reduced to a pair of halteres. These swing about like very high speed Indian clubs, which they resemble, functioning as tiny gyroscopes. We know these halteres are vestigial remains of wings for several reasons
- they occupy exactly the same place in the third segment of the thorax as the flying wing occupies in the second thoracic segment (and the third too in other insects).
- they move in a figure of eight pattern as the wings of flies.
- they have the same embryology as wings and, although they are tiny, if you look at them carefully, especially during development, you can see that they are stunted wings, clearly modified.
- all insect wings have tiny sense organs in the base, which detect twisting and other forces. The sense organs at the base of halteres are very similar.
Halteres on a craneflyHalteres are what makes between stable and unstable fliers. In any flying machine, there is a trade-off between stability and maneuverability. John Maynard Smith pointed out that animals lose inherent stability in the interests of increased maneuverability, but paying for it in the form of increased instrumentation and computation capability - brain power. The four winged ancestors of flies probably had long abdomens which would make them stable. All four wings would have acted as rudimentary gyroscopes. The ancestors of flies started to move along the stability continuum becoming more maneuverable and less stable as the abdomen got shorter. The hind wings started to shift more towards the gyroscopic function (which they had always performed, in a small way, as wings), becoming smaller, and heavier for their size, while the forewings enlarged to take over more of the flying. There would have been a gradual continuum of change, as the forewings assumed ever more of the burden of aviation, while the hind wings shrank to take over the avionics.
Worker ants have lost their wings, but not the capacity to grow wings. They lost their wings in evolution because they are a nuisance and get in the way underground. Queen ants and male ants have wings and worker ants are females who could have become queens but for environmental reasons (not genetic) failed to become queens. Queen ants use their wings only once, to fly out of the natal nest, find a mate and then settle down to dig a hole for a new nest. As they begin their new life underground the first thing they do is lose their wings, in some cases by literally biting them off.An additional reason for winglessness is an evolutionary defense mechanism of assuming a protective resemblance to ants, either (or both) to fool the ants or to fool would-be predators who might otherwise pick them out from among the less palatable and better protected ants.
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