Yourstone Johanna, Varadarajan Vidula, Olsson Ola
Department of Biology, Lund University, Sölvegatan 37, 223 62 Lund, Sweden and.
School of Arts and Science, Azim Premji University, Survey No 66, Burugunte Village, Bikkanahalli Main Road, Sarjapura, Bengaluru 562125, India.
Behav Ecol. 2023 Apr 10;34(4):602-612. doi: 10.1093/beheco/arad028. eCollection 2023 Jul-Aug.
Bees often focus their foraging effort on a few or even a single flower species, even if other equally rewarding flower species are present. Although this phenomenon-called flower constancy-has been widely documented during single foraging trips, it is largely unknown if the behavior persists over longer time periods, especially under field conditions with large temporal variations of resources. We studied the pollen diet of individuals from nine different colonies for up to 6 weeks, to investigate flower constancy and pollen diversity of individuals and colonies, and how these change over time. We expected high degrees of flower constancy and foraging consistency over time, based on foraging theory and previous studies. Instead, we found that only 23% of the pollen foraging trips were flower constant. The fraction of constant pollen samples did not change over the study period, although repeatedly sampled individuals that were flower constant once often showed different preferences at other sampling occasions. The similarity of pollen composition in samples collected by the same individuals at different occasions dropped with time. This suggests that the flower preferences change in response to shifting floral resources. The average diversity of pollen from single foraging trips was around 2.5 pollen types, while the colony-level pollen diversity was about three times higher. How rapidly preferences change in response to shifting resources, and if this differs between and within bee species depending on factors such as size, should be the focus of future research.
蜜蜂常常将其觅食精力集中在少数几种甚至单一的花卉物种上，即便存在其他同样能带来回报的花卉物种。尽管这种被称为“采花专一性”的现象在单次觅食行程中已有广泛记载，但在较长时间段内这种行为是否持续存在，尤其是在资源随时间大幅变化的野外条件下，却 largely unknown。我们对来自九个不同蜂群的个体的花粉食物进行了长达六周的研究，以调查个体和蜂群的采花专一性及花粉多样性，以及它们如何随时间变化。基于觅食理论和先前的研究，我们预期随着时间推移会有高度的采花专一性和觅食一致性。然而，我们发现只有23%的花粉觅食行程是采花专一的。恒定花粉样本的比例在研究期间没有变化，尽管那些曾有过一次采花专一行为的个体在其他采样时机常常表现出不同的偏好。同一蜜蜂个体在不同时间采集的样本中花粉成分的相似性随时间下降。这表明花卉偏好会随着花卉资源的变化而改变。单次觅食行程中花粉的平均多样性约为2.5种花粉类型，而蜂群层面的花粉多样性则高出约三倍。花卉偏好如何随着资源变化而迅速改变，以及这种变化在不同蜜蜂物种之间和同一物种内部是否因体型等因素而有所不同，应是未来研究的重点。
