title: Anisotropic shrinkage of insect air sacs revealed in vivo by X-ray microtomography.
abstract: Air sacs are thought to be the bellows for insect respiration. However, their exact mechanism of action as a bellows remains unclear. A direct way to investigate this problem is in vivo observation of the changes in their three-dimensional structures. Therefore, four-dimensional X-ray phase contrast microtomography is employed to solve this puzzle. Quantitative analysis of three-dimensional image series reveals that the compression of the air sac during respiration in bell crickets exhibits obvious anisotropic characteristics both longitudinally and transversely. Volumetric changes of the tracheal trunks in the prothorax further strengthen the evidence of this finding. As a result, we conclude that the shrinkage and expansion of the insect air sac is anisotropic, contrary to the hypothesis of isotropy, thereby providing new knowledge for further research on the insect respiratory system.
authors: Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China.|University of Chinese Academy of Sciences, Beijing 100049, China.
authors: Liang
authors: L
authors: Xu
authors: Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China.
authors: Rongchang
authors: R
authors: Chen
authors: Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China.
authors: Guohao
authors: G
authors: Du
authors: Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China.|University of Chinese Academy of Sciences, Beijing 100049, China.
authors: Yiming
authors: Y
authors: Yang
authors: Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China.|University of Chinese Academy of Sciences, Beijing 100049, China.
authors: Feixiang
authors: F
authors: Wang
authors: Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China.
authors: Biao
authors: B
authors: Deng
authors: Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China.
authors: Honglan
authors: H
authors: Xie
authors: Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China.|University of Chinese Academy of Sciences, Beijing 100049, China.
authors: Tiqiao
authors: T
authors: Xiao
mesh_terms: D000400:Air Sacs / Q000000981:diagnostic imaging*; D000818:Animals; D016880:Anisotropy; D021621:Imaging, Three-Dimensional; D007313:Insecta / Q000033:anatomy & histology*; D012119:Respiration; D055114:X-Ray Microtomography