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Structure, function and evolution of insect flight muscle

View Article: PubMed Central - PubMed

ABSTRACT

Insects, the largest group of animals on the earth, owe their prosperity to their ability of flight and small body sizes. The ability of flight provided means for rapid translocation. The small body size allowed access to unutilized niches. By acquiring both features, however, insects faced a new problem: They were forced to beat their wings at enormous frequencies. Insects have overcome this problem by inventing asynchronous flight muscle, a highly specialized form of striated muscle capable of oscillating at >1,000 Hz. This article reviews the structure, mechanism, and molecular evolution of this unique invention of nature.

No MeSH data available.


Relative occupancy of various structure in the volume of muscle cell. (a), ordinary skeletal muscle of rattlesnake; (b) sound-producing tail muscle of rattlesnake; (c) timbal muscle of cicada; (d) flight muscle of bee. Others refers to the volume not occupied by any of these organelles (myofibril, SR, mitochondria). Modified from ref. 6.
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f3-7_21: Relative occupancy of various structure in the volume of muscle cell. (a), ordinary skeletal muscle of rattlesnake; (b) sound-producing tail muscle of rattlesnake; (c) timbal muscle of cicada; (d) flight muscle of bee. Others refers to the volume not occupied by any of these organelles (myofibril, SR, mitochondria). Modified from ref. 6.

Mentions: Besides IFM, muscles that repeat high-frequency contraction-relaxation cycles are found among sound-producing animals. In this case, some muscles oscillate at above 100Hz even if they are “synchronous”. In these muscles, contractile force is sacrificed as a price for speed. A toadfish, for example, produces sound by oscillating its swimbladder at 200Hz. The fast contraction-relaxation cycles are made possible by reducing the time for actinmyosin binding at the expense of contractile force5. In the case of a rattlesnake, whose sound frequency goes up to 100 Hz, myofibrils occupy only 32% of the volume of the sound-producing muscle, while mitochondria and SR occupy 26% each6 (Fig. 3). In a more extreme case of a cicada (Hemiptera) that sings at 550 Hz, myofibrils occupy only 22% of the volume of the timbal muscle, while mitochondria and SR occupy 33% each6. Speed at the expense of force may be good for producing sound, but it is not a right strategy for IFMs that require large power output.


Structure, function and evolution of insect flight muscle
Relative occupancy of various structure in the volume of muscle cell. (a), ordinary skeletal muscle of rattlesnake; (b) sound-producing tail muscle of rattlesnake; (c) timbal muscle of cicada; (d) flight muscle of bee. Others refers to the volume not occupied by any of these organelles (myofibril, SR, mitochondria). Modified from ref. 6.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5036774&req=5

f3-7_21: Relative occupancy of various structure in the volume of muscle cell. (a), ordinary skeletal muscle of rattlesnake; (b) sound-producing tail muscle of rattlesnake; (c) timbal muscle of cicada; (d) flight muscle of bee. Others refers to the volume not occupied by any of these organelles (myofibril, SR, mitochondria). Modified from ref. 6.
Mentions: Besides IFM, muscles that repeat high-frequency contraction-relaxation cycles are found among sound-producing animals. In this case, some muscles oscillate at above 100Hz even if they are “synchronous”. In these muscles, contractile force is sacrificed as a price for speed. A toadfish, for example, produces sound by oscillating its swimbladder at 200Hz. The fast contraction-relaxation cycles are made possible by reducing the time for actinmyosin binding at the expense of contractile force5. In the case of a rattlesnake, whose sound frequency goes up to 100 Hz, myofibrils occupy only 32% of the volume of the sound-producing muscle, while mitochondria and SR occupy 26% each6 (Fig. 3). In a more extreme case of a cicada (Hemiptera) that sings at 550 Hz, myofibrils occupy only 22% of the volume of the timbal muscle, while mitochondria and SR occupy 33% each6. Speed at the expense of force may be good for producing sound, but it is not a right strategy for IFMs that require large power output.

View Article: PubMed Central - PubMed

ABSTRACT

Insects, the largest group of animals on the earth, owe their prosperity to their ability of flight and small body sizes. The ability of flight provided means for rapid translocation. The small body size allowed access to unutilized niches. By acquiring both features, however, insects faced a new problem: They were forced to beat their wings at enormous frequencies. Insects have overcome this problem by inventing asynchronous flight muscle, a highly specialized form of striated muscle capable of oscillating at >1,000 Hz. This article reviews the structure, mechanism, and molecular evolution of this unique invention of nature.

No MeSH data available.