Osorio-Canadas Sergio, Flores-Hernández Noé, Sánchez-Ortiz Tania, Valiente-Banuet Alfonso
Departamento de Ecología de la Biodiversidad, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico.
Escuela Nacional de Trabajo Social, Universidad Nacional Autónoma de México, Mexico City, Mexico.
Oecologia. 2022 Oct;200(1-2):145-158. doi: 10.1007/s00442-022-05248-y. Epub 2022 Sep 2.
Understanding the causes of morphological variation of organisms along climatic gradients has been a central challenge in ecological research. We studied the variation of community weighted mean (CWM) and two functional diversity metrics (Rao-Q and functional richness) computed for five morphological traits of wild bees (Hymenoptera: Apoidea) related to thermal performance (namely body size, relative appendage length and hairiness), at community and interspecific levels, along an elevation gradient in a Mexical-type scrubland. At the community level we found a decreasing CWM of body size pattern with increasing elevation which is consistent with the species-energy theory (and contrary to Bergmann's rule). We also found an increase in the CWM of relative tibia length, which is contrary to Allen's rule. Additionally, we found an increase in the CWM of relative hair length towards high levels of elevation, which would be consistent with the hypothesis that hairiness plays an important role as thermal insulation. We found that functional diversity was larger at low elevations with respect to high elevation for body size and hair length, which could imply that highland communities were more sensitive towards environmental changes than lowland communities. Overall, at intraspecific level, most of species showed no pattern for any of the traits along the elevation gradient. Future research should provide further evidence on the possible behavioral or physiological mechanisms behind it.
理解生物体形态变异沿气候梯度变化的原因一直是生态学研究的核心挑战。我们研究了在墨西哥型灌丛地沿海拔梯度，在群落和种间水平上，针对野生蜜蜂（膜翅目：蜜蜂总科）与热性能相关的五个形态特征（即体型、相对附肢长度和多毛程度）计算的群落加权均值（CWM）以及两个功能多样性指标（Rao - Q和功能丰富度）的变异情况。在群落水平上，我们发现随着海拔升高，体型模式的CWM呈下降趋势，这与物种 - 能量理论一致（与伯格曼法则相反）。我们还发现相对胫骨长度的CWM增加，这与艾伦法则相反。此外，我们发现相对毛发长度的CWM随着海拔升高而增加，这与多毛程度作为隔热起重要作用的假设一致。我们发现，就体型和毛发长度而言，低海拔地区的功能多样性相对于高海拔地区更大，这可能意味着高地群落比低地群落对环境变化更敏感。总体而言，在种内水平上，大多数物种在沿海拔梯度的任何性状上都没有表现出规律。未来的研究应该为其背后可能的行为或生理机制提供进一步的证据。
