A Beetle Flight Muscle Displays Leg Muscle Microstructure

Toshiki Shimomura, Hiroyuki Iwamoto, Tat Thang Vo Doan, Shin'ichi Ishiwata, Hirotaka Sato*, Madoka Suzuki


研究成果: Article査読

8 被引用数 (Scopus)


In contrast to major flight muscles in the Mecynorrhina torquata beetle, the third axillary (3Ax) muscle is a minor flight muscle that uniquely displays a powerful mechanical function despite its considerably small volume, ∼1/50 that of a major flight muscle. The 3Ax muscle contracts relatively slowly, and in flight strongly pulls the beating wing to attenuate the stroke amplitude. This attenuation leads to left-right turning in flight or wing folding to cease flying. What enables this small muscle to be so powerful? To explore this question, we examined the microstructure of the 3Ax muscle using synchrotron x-ray diffraction, optical microscopy, and immunoblotting analysis. We found that the 3Ax muscle has long (∼5 μm) myofilaments and that the ratio of thick (myosin) filaments to thin (actin) filaments is 1:5 or 1:6. These characteristics are not observed in the major flight muscles, which have shorter myofilaments (∼3.5 μm) with a smaller ratio (1:3), and instead are more typical of a leg muscle. Furthermore, the flight-muscle-specific troponin isoform, TnH, is not expressed in the 3Ax muscle. Since such a microstructure is suitable for generating large tension, the 3Ax muscle is appropriately designed to pull the wing strongly despite its small volume.

ジャーナルBiophysical Journal
出版ステータスPublished - 2016 9月 20

ASJC Scopus subject areas

  • 生物理学


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