A
male of Eucera nigrilabris is visiting a Moricandia arvensis
flower
(from Gomez et al. 2025; https://doi.org/10.1093/aobpla/plae065).
by Torices et al.
Plants often grow in clusters rather than as isolated individuals. We asked whether pollinators respond mainly to how many plants are grouped together or to how many flowers the group displays. To answer this, we created experimental patches of the Mediterranean plant Moricandia arvensis, varying independently the number of plants and the total number of open flowers. We recorded how often insect pollinators visited these patches and how they moved among plants and flowers. Most visits were made by long-tongued solitary bees, especially Anthophora and Eucera, which are the main spring pollinators of this species. The number of open flowers in a patch was the strongest factor attracting pollinators: patches with more flowers received more visits, particularly when they contained many plants. However, individual flowers in large displays received fewer visits on average. The number of plants alone had weaker effects, but it influenced how strongly flower number increased pollinator attraction. In fact, adding flowers made patches much more attractive when those flowers were spread across many plants than when the flowers were arranged in a few plants. Overall, our results show that the way plants are grouped affects pollinator behaviour in ways that cannot be explained simply by the number of flowers within a patch.
