Karan Dev, Dahiya Neena, Munjal Ashok K, Gibert Patricia, Moreteau Brigitte, Parkash Ravi, David Jean R
Department of Biosciences, Maharshi Dayanand University, Rohtak, 124 001, India.
Laboratoire Populations, Génétique et Evolution, CNRS, 91198, Gif sur Yvette Cedex, France.
Evolution. 1998 Jun;52(3):825-831. doi: 10.1111/j.1558-5646.1998.tb03706.x.
Desiccation and starvation tolerance were measured along latitudinal transects in three Drosophilid species (Drosophila ananassae, D. melanogaster, and Zaprionus indianus) of the Indian subcontinent. In each case, significant latitudinal clines were observed; desiccation tolerance increased with latitude while starvation tolerance decreased. Such field observations suggest that desiccation and starvation tolerance are fitness related traits that are independently selected in nature and genetically independent. It was, however, difficult to relate these genetic changes with precise climatic variables, except winter temperature. The overall negative correlation between the two traits, which was evidenced in natural populations, contrasts with a positive correlation generally observed in various laboratory selection experiments and that also seems to exist between different species. These observations point to the difficulty of interpreting correlations among fitness-related traits when different evolutionary levels are compared, and also different sets of data, that is, field versus laboratory studies.
在印度次大陆的三种果蝇（拟果蝇、黑腹果蝇和印度扎氏果蝇）中，沿着纬度梯度对干燥耐受性和饥饿耐受性进行了测量。在每种情况下，都观察到了显著的纬度渐变群；干燥耐受性随纬度增加，而饥饿耐受性则降低。此类实地观察表明，干燥耐受性和饥饿耐受性是与适应性相关的性状，在自然界中是独立选择的，并且在基因上是独立的。然而，除了冬季温度外，很难将这些基因变化与精确的气候变量联系起来。在自然种群中得到证明的这两个性状之间的总体负相关，与在各种实验室选择实验中通常观察到的正相关形成对比，并且这种正相关似乎在不同物种之间也存在。这些观察结果表明，当比较不同的进化水平以及不同的数据集（即实地研究与实验室研究）时，解释与适应性相关的性状之间的相关性存在困难。
