In plant–pollination interactions, the antagonists collect the same set of resources offered to legitimate visitors, but their morphologies and behavioural approaches possibly make their effect on plant fitness negative rather than positive. Depending on the morphology of Malpighiaceae flowers, these small-bodied bees can adopt an upside-down position, biting and damaging the floral pedicel. Therefore, we hypothesized that small-bodied bees may reduce female reproductive fitness, due to increased floral abscission. We observed small Tetrapedia bees approaching bagged and unbagged flowers of Peixotoa tomentosa, and compared abscission rates associated with the upside-down behavior performance. When Tetrapedia bees exhibited the upside-down behaviour the floral abscission was about 1.7 times more frequent than without this behaviour. We observed that abscission frequency increased to 80% if upside-down behavior is performed at least three times per flower. Additionally, the frequency of upside-down behaviours were positively related to the number of flowers visited per plant. Overall, the upside-down behaviour of Tetrapedia compromised most flowers that were viable for fruit formation, potentially decreasing the female reproductive fitness of plant population. We emphasize that different roles of floral visitors, including the robbers, are associated with visitors’ body size and behaviour. Such features of interactions determine whether floral visitors are pollinators, thieves or robbers and shape a continuum from mutualistic to antagonistic interactions.

中文翻译：

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抢劫之外：小型采油蜂在马尔皮科中的颠倒行为的作用

在植物与授粉的相互作用中，拮抗剂收集提供给合法访客的同一组资源，但是它们的形态和行为方式可能使它们对植物适应性的影响为负而不是正。这些小体蜂可能会根据Malpighiaceae花朵的形态而采取颠倒的姿势，咬住并伤害花梗。因此，我们假设小花蜂可能由于增加的花脱落而降低雌性繁殖能力。我们观察到小型四足蜂接近袋装和无袋装花朵的花朵，并比较了与倒立行为表现相关的脱落率。当四足动物蜜蜂表现出上下颠倒的行为，花脱落现象的发生频率是没有这种行为的1.7倍。我们观察到，如果每朵花至少进行3次颠倒行为，则脱落频率增加到80％。另外，倒挂行为的频率与每株植物探望的花朵数量成正相关。总体而言，四足动物的倒立行为损害了大多数可形成果实的花朵，可能降低植物种群的雌性繁殖能力。我们强调，花卉游客（包括强盗）的不同角色与游客的体型和行为有关。相互作用的这种特征决定了花访客是否是传粉者，小偷或强盗，并形成了从相互影响到对抗性相互作用的连续体。