Data from: Tracheal compression in pupae of the beetle Zophobas morio

Insects that are small or exhibit low metabolic rates are considered to not require active ventilation to augment diffusive gas exchange. Some pupae with low metabolic rates exhibit abdominal pumping, a behaviour that is known to drive tracheal ventilation in the adults of many species. However, previous work on pupae suggests that abdominal pumping may serve a non-respiratory role. To study the role of abdominal pumping in pupa of the beetle Zophobas morio, we visualized tracheal dynamics with X-rays while simultaneously measuring haemolymph pressure, abdominal movement, and CO2 emission. Pupae exhibited frequent tracheal compressions that were coincident with both abdominal pumping and pulsation of pressure in the haemolymph. However, more than 63% of abdominal pumping events occurred without any tracheal collapse and hence ventilation, suggesting that the major function of the abdominal pump is not respiratory. In addition, this study shows that the kinematics of abdominal pumping can be used to infer the status of the spiracles and internal behaviour of the tracheal system.

体型微小或代谢率较低的昆虫，通常被认为无需借助主动通气来强化扩散式气体交换。部分代谢率较低的蛹会展现腹部泵动行为——这类行为在多数昆虫成虫中已被证实可驱动气管通气。不过，过往针对蛹的研究显示，腹部泵动可能具有非呼吸功能。为探究大麦虫（Zophobas morio）蛹的腹部泵动功能，我们通过X射线可视化观察气管动态变化，同时同步测定血淋巴压力、腹部运动与二氧化碳排放情况。研究观察到蛹会频繁出现气管压缩现象，且该现象与腹部泵动及血淋巴压力搏动同步发生。不过，超过63%的腹部泵动事件并未伴随气管塌陷，也就无法实现通气，这表明腹部泵动的主要功能并非呼吸相关。此外，本研究证实，可通过腹部泵动的运动学特征推断昆虫气门状态以及气管系统的内部行为。