Altitudinal clinal variation in wing form in African Drosophila melanogaster: one cline or many?

Geographical patterns of morphological variation have been useful in addressing hypotheses about environmental adaptation. In particular, latitudinal clines in phenotypes have been studied in a number of Drosophila species. Some environmental conditions along latitudinal clines—for example, temperature—also vary along altitudinal clines, but these have been studied infrequently and it remains unclear whether these environmental factors are similar enough for convergence or parallel evolution. Most clinal studies in Drosophila have dealt exclusively with univariate phenotypes, allowing for the detection of clinal relationships, but not for estimating the directions of covariation between them. We measured variation in wing shape and size in D. melanogaster derived from populations at varying altitudes and latitudes across sub-Saharan Africa. Geometric morphometrics allows us to compare shape changes associated with latitude and altitude, and manipulating rearing temperature allows us to ...形态变异的地理分布模式，在验证环境适应性相关假说方面具有重要应用价值。具体而言，多个果蝇属（Drosophila）物种的表型纬度渐变群已得到广泛研究。纬度渐变群伴随的部分环境条件（例如温度），同样会随海拔渐变群发生变化，但相关研究较为匮乏，目前仍不清楚这些环境因子的相似性是否足以促成趋同演化或平行演化。多数果蝇类群的渐变群研究仅聚焦于单变量表型，仅能检测渐变关系，却无法估算表型间的协变方向。我们对采集自撒哈拉以南非洲不同海拔与纬度种群的黑腹果蝇（Drosophila melanogaster）的翅形与翅大小变异进行了测定。几何形态测量学（Geometric morphometrics）可帮助我们对比与纬度和海拔相关的翅形变化，而通过调控饲养温度，我们能够……