Declines in wild bee abundance and diversity may have cascading effects throughout ecosystems as well as negatively impact food security. Understanding the scale at which wild bees forage within agricultural landscapes is an important component of developing effective pollinator conservation strategies. Foraging ranges of wild bee species can provide insight into the extent to which wild bees pollinate crops. In the southern Great Plains, Brassica napus (canola) is an important edible oil, oilseed meal, and biofuels crop that benefits from bee pollination. We measured body size of three common wild bee species at increasing distances into canola fields (75, 150, and 300 m), as well as landscape characteristics and seed set of canola. We found positive intraspecific correlations between body size and distance into canola fields for two of the species, as well as seed set and distance into canola fields. We also found correlations between land use and body size across three nested spatial scales (250 m, 500 m, and 1 km). As the area of grass and pasture increased so did the body size of Agapostemon texanus (Cresson), whereas the body size of Lasioglossum disparile (Cresson) decreased. As the area of development increased, the body size of Colletes mandibularis (Smith) decreased. Body size variation at the population level may have implications for pollination efficacy and foraging ranges of wild bees and should be considered in future studies, particularly with a more robust sample size. Furthermore, intraspecific variation in body size may provide insights into species level responses to land use change and other environmental stressors.

野生蜂数量和多样性的下降可能对整个生态系统产生连锁效应，并对粮食安全产生不利影响。了解野生蜜蜂在农业景观中觅食的规模是制定有效的传粉媒介保护策略的重要组成部分。野蜂物种的觅食范围可以洞察野蜂对农作物授粉的程度。在大平原南部，甘蓝型油菜芥花籽油（油菜籽）是一种重要的食用油，油籽粉和生物燃料作物，得益于蜜蜂授粉。我们在油菜田（75、150和300 m）中增加距离的情况下，测量了三种常见的野生蜂物种的体型，以及油菜的景观特征和种子集。我们发现了两个物种的体型与到油菜田中的距离以及种子集和到油菜田中的距离之间的正种内相关性。我们还发现，在三个嵌套的空间尺度（250 m，500 m和1 km）中，土地利用与体重之间存在相关性。随着草场和牧场面积的增加，Agapostemon texanus（Cresson）的体型也随之增加，而Lasioglossum的体型却不一样（Cresson）减少。随着发育面积的增加，下颌Colletes mandibularis（Smith）的体型减小。种群水平的体型变化可能对授粉效果和野生蜂的觅食范围有影响，应在以后的研究中予以考虑，尤其是在样本量更大时。此外，体内种内差异可能提供对物种水平对土地利用变化和其他环境压力的响应的洞见。