为了弥补其庞大的身躯带来的不便，大多数大型昆虫发展出了一种特殊的呼吸方式：他们像肚皮舞娘那样张驰腹部来排出二氧化碳，同时将氧气经由气管套管送入其余的细胞。但在很长一段时间内，科学家们以为只有大型或特别活跃的昆虫才会采取这种主动呼吸的方式。现在，研究人员发现，伪步行虫(Zophobas morio，上图)的小蛹也会同样的腹部张驰法。但这是为了帮助呼吸吗?为了找到答案，研究人员用高功率X射线成像技术来观察昆虫呼吸导管何时萎陷——主动呼吸的一个明确现象。他们还测量了腹部泵气和体外气体交换的速率，以及血淋巴(血)压。正如预想的那样，腹部泵气导致血压升高、气管萎陷、二氧化碳排出——换言之就是呼吸。但蛹张驰腹部的情况中只有37%是因为呼吸，研究团队在本月的Biology Letters上报告说。其他情况下并没有出现气管萎陷或气体交换，这让研究人员相信“充气术”可能还有其他功能——主流的看法各种各样，有的说是帮助体内气体混合，有的说是促进血液循环。

    原文链接：Video: Young beetles pump their abs to breathe

    原文摘要：o compensate for their large size, most big insects have developed a special way of breathing: They flex their abdomens like belly dancers to pump out carbon dioxide and to push oxygen through their tracheal tubes into the rest of their cells. But for a long time, scientists assumed this kind of active ventilation happened only in large or particularly active bugs. Now, researchers have discovered that the tiny pupae of the darkling beetle (Zophobas morio, above) exhibit the same type of abdominal flexing. But does it serve a role in breathing? To find out, the researchers used high-powered x-ray imaging to observe when the insects’ breathing tubes collapsed—a sure sign of active ventilation. They also measured rates of abdominal pumping and external gas exchange along with hemolymph (blood) pressure. As expected, abdominal pumping resulted in high blood pressure, tracheal collapse, and carbon dioxide release—that is, breathing. But this happened only 37% of the time the pupae were flexing their abs, the team reports this month in Biology Letters. The rest of the time, there was no tracheal collapse or gas exchange, leading researchers to believe that the pumping could serve other functions, from internal gas mixing to—the leading theory—blood circulation.