树麻雀表型的环境适应进化

树麻雀(Passer montanus)分布范围广、海拔梯度大,也是人类活动的伴随物种。对中国837个样本的10个形态特征与温度、日照、海拔和风速等4个主要环境因子进行相关分析,结果显示:树麻雀的体重、嘴裂、翅长、尾长、跗跖长、脑骨宽、眼间距与日照因子显著相关(P0.05),体重、体长、翅长、尾长、跗跖长与海拔因子显著相关(P0.05),体重、嘴峰、翅长、脑骨长与温度因子显著相关(P0.05),表明树麻雀的形态指标易随环境因子的变化而变化。通过控制经度和海拔两个变量,对形态指标与纬度的偏相关分析表明,体重、翅长、脑骨长和脑骨宽与纬度呈显著正相关(P0.05),体表突出部分嘴峰、嘴裂与纬度呈显著负相关(P0.05),即随着纬度的升高,树麻雀身体逐渐变大,符合贝格曼规律;体表突出部分嘴峰和嘴裂随纬度升高变短,符合阿伦规律。飞行能力与海拔因子呈极显著正相关(n=92,r=0.217,P=0.038),表明树麻雀在高海拔地区具有更强的飞行能力,这也许是它成为广布种的重要原因。

The adaptive evolution of the Tree Sparrow (Passer montanus) phenotype to environment factors

Observed across a large altitudinal gradient and a widely-distributed geographical range, the tree sparrow (Passer montanus) is a species commonly associated with human beings. This study analyzed the relationship between 10 morphological characteristics of 837 tree sparrows sampled, and 4 environmental factors (air temperature factor, sunshine factor, altitude factor, and air-speed factor). The results indicated that morphological traits, such as body weight, rictus, wing length, tail length, tarsus length, skull width, and interorbital distance were significantly correlated with the sunshine factor (P<0.05). Moreover, body weight, body size, wing length, tail length, and tarsus length were significantly correlated with the altitude factor (P<0.05). Additionally, body weight, culmen length, wing length, and skull length were significantly correlated with the air temperature factor (P<0.05). The aforementioned findings suggest that these morphological characteristics have adaptive potential in response to environmental factors. Furthermore, we analyzed the relationship between morphological size and latitude by controlling for longitude and altitude. The results of this analysis indicated that body weight, wing length, and skull size had a significant positive correlation with the latitude factor (P<0.05). Conversely, culmen length and rictus had a significant negative correlation with latitude (P<0.05) after controlling for longitude and altitude. These findings suggest that body size increases with rising latitude, while bill size decreases with increased latitude. Therefore, we conclude that the morphological variation of this species is in concordance with Bergmann''s rule and Allen''s rule. A significant positive relationship was found between flight ability and the altitude factor (n=92, r=0.217, P=0.038), and thus our results postulate that the flight ability of P. montanus is greater at higher altitudes than at lower altitudes. This adaptive component of flight ability may offer an explanation as to why P. montanus is so widely-distributed throughout the planet.