Schmitz Anke, Perry Steven F
Institut für Zoologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Poppelsdorfer Schloss, 53115 Bonn, Germany.
Arthropod Struct Dev. 2002 Feb;30(3):229-41. doi: 10.1016/s1467-8039(01)00037-8.
The tracheal system of harvestmen consists of two stem tracheae, which give rise to higher order tracheae that supply the extremities and internal organs. In this study, we used stereological morphometric methods to investigate diffusing capacities of the walls ('lateral diffusing capacity') of the tracheae of adult males and females of Nemastoma lugubre. Diffusing barriers of the tracheal walls tend to be thinnest (0.17-0.19 microm) for the smallest tracheae (inner diameter 0.5-2 microm). In other tracheal classes the diffusing barriers increase with increasing diameters. Calculation of the mass-specific diffusing capacity for oxygen (D(O2)) of the walls of all higher order tracheae revealed 10.57 microl min(-1)g(-1)kPa(-1) for the females (mean body mass 3.8 mg) and 25.23 microl min(-1)g(-1)kPa(-1) for the males (mean body mass 1.4 mg). In both animal groups, the main D(O2) (58-67%) lies in the tracheae with an inner diameter of 0.5-2 microm, but also tracheae up to an inner diameter of 20 microm allow gas exchange via the tracheal walls. Stem tracheae are of no importance for lateral diffusion. Our results are consistent with the hypothesis that the functional morphology of the tracheal system of harvestmen represents an 'intermediate state' between the tracheal system of insects in which gas exchange is focused on the distal portions and that of spiders, in which the walls of all tracheae serve in gas exchange.
盲蛛的气管系统由两条主气管组成，由此产生的高阶气管为肢体和内部器官提供氧气。在本研究中，我们使用体视学形态测量方法，研究了暗色 Nemastoma 成年雄性和雌性气管壁的扩散能力（“横向扩散能力”）。气管壁的扩散屏障对于最小的气管（内径 0.5 - 2 微米）往往最薄（0.17 - 0.19 微米）。在其他气管类别中，扩散屏障随着直径的增加而增加。对所有高阶气管壁的氧气质量比扩散能力（D(O2)）的计算显示，雌性（平均体重 3.8 毫克）为 10.57 微升·分钟⁻¹·克⁻¹·千帕⁻¹，雄性（平均体重 1.4 毫克）为 25.23 微升·分钟⁻¹·克⁻¹·千帕⁻¹。在这两个动物组中，主要的 D(O2)（58 - 67%）存在于内径为 0.5 - 2 微米的气管中，但内径达 20 微米的气管也允许通过气管壁进行气体交换。主气管对横向扩散不重要。我们的结果与以下假设一致，即盲蛛气管系统的功能形态代表了昆虫气管系统（气体交换集中在远端部分）和蜘蛛气管系统（所有气管壁都参与气体交换）之间的“中间状态”。
