Summary of Alternative Theory of Flight
Today the visual and sonic functions of the flight mecahnism are active in insect bechavior.
The alternate theory proposes that these functions predate flight and provide the machanical basis for it.
If the capability if flight is reduced -- perhaps to its primitive stage -- to a point when it could not effect flight, even then the visual and sonic functions would be available.
But on what basis do we any reason to reverse development? Because without wings the flight mechanism can be viewed as a vibrating mechanism which can be translated into visual and sonic tools of communication.
Now, if we accept that communication, whether visual or sonic, is a fundamental element of insect behavior and if we also accept that the evolution of visual or sonic mechanical elements is far simpler to achieve than the complex, specialized engineering of
the flight mechanism, then it is reasonable to also accept that such commination must have been widely distributed among pre-flight insects and it would undergo considerable devlopment. We can, therefore, in theory, construct out of this state an origin fo
r flight out of a communicative structure in the thoraxic region. This structure most likely would be a pulsing or vibrational mechanism.
This way we gain an advantage: instead of emtertaining one or more unknown variables, we have a theory of flight that needs to explain relatively little. The fundamentals of flight are latent in the vibratory mechanism and so that mechanism can make flight
possible as soon as wings are added.
The wing
To explain how wings would appear is also simplified because we can provide an adaptive function to such objects as paranotal lobes, even at a primitive stage of development. An initially emerging structural anomaly can produce sonic or visual data with les
s design requirements and at far lesser magnitude than a lobe would in its proposed protective or aerodynamic roles.
Direct or Indirect and Sonic or Visual
A point needs to be cleared up. We have talked about sonic and/or visual functions and indirect and/or direct muscluar mechanisms, and have not interchanged them without much discrimination. The reason is that at this point the only option we have is to off
er an exteremely theoretical list of possible forms for the vibrating mechanism.
The original function of the vibrator could have been either sonic or visaul. Sonic events can occur with structures of considerably lesser magnitude than visual ones would occur, so perhaps a sonic choice had more probability. But, since as soon as the pre
cursors of wings, steming from sonic origin, reached sufficient size and mobility, a visual function would also emerge and would be combined with the sonic one.
As to the dinstiction between the tymbal-type vibrator, powered by a direct muscle and the thoracic deformation with the click emchanism, that can also not be elabortad on. Still, we can say that if the leg muscles (presently shared with the wing mwchanism)
were original, then perhaps the function was visual. The reason is that the movements of the coxa is quite slow compared to potential seed of a click mechanism, and so the latter would be better set for sound production. Of course, the leg muscles could a
lso have played the role of modulatiing the action of the sonic vibrator. See ILL: possible alternatives
A major supportive point of the tymbal-wing analogy is that in their f\basic form bpth invplve musc;e-membrane interadtion, passed thpugh the sclerittes bases, and both involve an advantage gained by muscle due to the snap-back nature of the elastic mater
ila. Bothe the tumbal and the wing mechanism can be viewed a multiuvibrators. The extant click mechanism is bistable multivibrator, while the tymbal is a monstable one. Hwever, in these terms, the click mechanism can also be viewed as a set of two moostable
s which share an unstable position. ILL. And as /we have senn in ILL or p. 000/ a simple model of a set of tymbals sharing one border can create the same mechanism.
The weak points
1. Confused: original vibratory mechanism variants are not clearly distinguished. No clears leads offered here.
2. Propsed source of flight is not conncected with flight. The paranotal lobes on our fossils seem to carry a gretaer degree of direct realtion to flight than our somewhate removed source.
However, this difficulty may actually be a positive quality. Many evolutionary developments have come from unexpected osurces.
a. Rapidly running herbivorous and carnivorous mammals attained longer legs not through elongation of the leg bones, but of the foot bones.
b. The vertabrate jaw and auditory structure descend from ancestral gill arches.
itt tartok 1/Wed.