General Zoology, Institute for Biology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120, Halle (Saale), Germany.
German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, 04103, Leipzig, Germany.
BMC Ecol Evol. 2022 Aug 2;22(1):94. doi: 10.1186/s12862-022-02048-z.
To accommodate an ever-increasing human population, agriculture is rapidly intensifying at the expense of natural habitat, with negative and widely reported effects on biodiversity in general and on wild bee abundance and diversity in particular. Cities are similarly increasing in area, though the impact of urbanisation on wild bees is more equivocal and potentially positive in northern temperate regions. Yet agriculture and urbanisation both lead to the loss and alteration of natural habitat, its fragmentation, a potential reduction in floral availability, and warmer temperatures, factors thought to be drivers of wild bee decline. They have also been shown to be factors to which wild bee populations respond through morphological change. Body size is one such trait that, because of its relation to individual fitness, has received growing attention as a morphological feature that responds to human induced modification in land use. Here, we investigated the change in body size of two sympatric orchid bee species on the Yucatan Peninsula of Mexico in response to urbanization and agricultural intensification. By measuring 540 male individuals sampled from overall 24 sites, we found that Euglossa dilemma and Euglossa viridissima were on average smaller in urban and agricultural habitats than in natural ones. We discuss the potential role of reduced availability of resources in driving the observed body size shifts. Agricultural and urban land management in tropical regions might benefit wild bees if it encompassed the planting of flowering herbs and trees to enhance their conservation.
为了容纳不断增长的人口，农业正在以牺牲自然栖息地为代价快速集约化，这对生物多样性产生了负面的、广泛报道的影响，特别是对野生蜜蜂的数量和多样性。城市的面积也在同样增加，尽管城市化对野生蜜蜂的影响在北温带地区更为不确定，也可能是积极的。然而，农业和城市化都会导致自然栖息地的丧失和改变、栖息地的破碎化、花卉供应的潜在减少以及温度升高，这些因素被认为是导致野生蜜蜂数量减少的原因。它们也被证明是野生蜜蜂种群通过形态变化来应对的因素。体型是一个这样的特征，由于它与个体适应性有关，因此作为一种对土地利用人为改变做出反应的形态特征，越来越受到关注。在这里，我们调查了墨西哥尤卡坦半岛两种共生兰花蜜蜂物种的体型变化，以应对城市化和农业集约化。通过测量从 24 个总体样本中采集的 540 只雄性个体，我们发现 Euglossa dilemma 和 Euglossa viridissima 在城市和农业生境中的平均体型比在自然生境中要小。我们讨论了资源减少的潜在作用可能是导致观察到的体型变化的原因。如果热带地区的农业和城市土地管理包括种植开花草本植物和树木，以增强其保护，那么这可能对野生蜜蜂有益。
