Williams A E, Bradley T J
Department of Ecology and Evolutionary Biology, University of California, Irvine 92697, USA.
J Exp Biol. 1998 Nov;201(Pt 21):2953-9. doi: 10.1242/jeb.201.21.2953.
We measured CO2 and H2O release from individual fruit flies from five populations of Drosophila melanogaster selected for resistance to desiccation (D flies). Our previous work found that these flies survive for an extended period in dry air, have an increase in the peak height and frequency of CO2 release, as measured by the standard error of a linear regression (SER) of CO2 release for the entire survival period, and have reduced water loss rates (VH2O) compared with their control or ancestor populations. In the present study, we examined the following respiratory characteristics: VCO2, VH2O, the SER of CO2 release and the ratio of VCO2 to VH2O in the D flies. Correlations between these characters were calculated in order to determine the effect of respiratory pattern on water loss. We found that, within the D flies, neither periodic release of CO2 nor an increased SER for CO2 release was associated with reduced water loss. In addition, an increased SER was positively correlated with both an increased water loss rate and a decreased survival time. Therefore, although selection for desiccation resistance leads to both an increased SER and a decreased rate of water loss in the D flies, the increased SER does not significantly reduce respiratory water loss.
我们测量了来自五个经抗干燥选择的黑腹果蝇种群（D果蝇）的单个果蝇释放的二氧化碳和水。我们之前的研究发现，这些果蝇在干燥空气中能存活较长时间，通过整个存活期二氧化碳释放的线性回归标准误差（SER）测量，其二氧化碳释放的峰值高度和频率增加，并且与对照或祖先种群相比，水分流失率（VH2O）降低。在本研究中，我们检查了D果蝇的以下呼吸特征：VCO2、VH2O、二氧化碳释放的SER以及VCO2与VH2O的比率。计算了这些特征之间的相关性，以确定呼吸模式对水分流失的影响。我们发现，在D果蝇中，二氧化碳的周期性释放和二氧化碳释放SER的增加均与水分流失减少无关。此外，SER的增加与水分流失率的增加和存活时间的减少均呈正相关。因此，尽管对抗干燥的选择导致D果蝇的SER增加和水分流失率降低，但SER的增加并未显著减少呼吸水分流失。
