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Moment of Inertia and Mutilation Studies of an Insect Wing

97

further due to its great significance in the design of bio-mimicking Insect-based

MAVs (Chari. N–Personal Communication).

Itmaybementionedthattheseexperimentshavebeencarriedoutinatetheredstate

of the insect by using a stroboscope and the frequency values were also confirmed

by applying Mass Flow Theory. The bio-acoustic analysis of the frequency of the

mutilated fliers can also be done by feeding the sound to a Cathode Ray Oscillo-

scope (CRO) through a microphone and recording the flight pattern of the wing for

subsequent Fourier analysis studies. The main aim of the mutilation experiments

is to know how the various sections of the wing contribute to the development of

aerodynamic forces indirectly by comparing them with normal ones.

It has to be mentioned that T. javanica has a wingbeat frequency of 50 Hz and still

we classify it as a myogenic flier though T. javanica belongs to Pentatomidae. These

bugs, because of their sedentary lifestyle, secondarily, have reduced their frequency

of flight during the course of evolution lasting from Eocene (period covering about 60

million years). However, surprisingly, the muscles still retain their myogenic struc-

ture. This might be due to some disuse atrophy effect on the wingbeat frequency

during the prolonged course of evolution due to sedentary feeding habits of T.

javanica on the soapnut and other related trees.

At this juncture, it may be summarized that the insect once mutilated is not able

to fly in nature with mutilated wings. Similarly, wingtip loading was done on T.

javanica by fixing an additional mass of about 7 mg (in steps of 0.5 mg) to the

wingtips to know the effect of wingtip loading. It was observed that the wingbeat

frequency decreases by about 50% in such cases. Such experiments on T. javanica

would help in the designing of MAVs with wings of lower frequency.

Apositivecorrelationexistsbetweentheincreasingmassoftheflierandincreasing

wingspan as shown in Fig. 7.5. By careful observations, it can be noticed that the

wingspan values do not increase further beyond a mass of 1 gm. With a further

increase in mass, an increase in the value of effective breadth cannot be ruled out to

cater to the flight requirement. The wingspan value plays a vital role in understanding

the MI and the wingbeat frequency of insect wings.