East Tennessee State University, Johnson City, TN, 37614, USA.
Oecologia. 2020 Apr;192(4):1037-1045. doi: 10.1007/s00442-020-04637-5. Epub 2020 Apr 9.
Plant-pollinator network studies have uncovered important generalities in the structure of these communities, rapidly advancing our understanding of the underlying drivers of such a structure. In spite of this, however, it is still unclear how changes in structural network properties influence overall plant pollination success. One key limitation is the lack of information on the relationship between network structural properties and aspects of pollination and plant reproductive success. Here, we estimate four plant species network structural metrics (interaction strength, weighted degree, closeness centrality, and specialization level), commonly used to describe their importance within plant-pollinator networks, at two different sites, and evaluate their effects on pollen deposition and pollen tube success. We found a positive effect of plant-pollinator specialization and a negative effect of closeness centrality on heterospecific pollen load size. We also found a marginal negative effect of closeness centrality on pollen tube success. Our results suggest that increasing plant-pollinator specialization within nested communities (pollinated by one or very few generalist insect species) may result in high levels of heterospecific pollen transfer. Furthermore, the differential effects of plant-pollinator network metrics on pollination success (pollen receipt and pollen tube success), highlight the need to integrate quantity (e.g. visitation rate) and quality (e.g. pollen delivery) aspects of pollination to achieve a more mechanistic understanding of the relationship between plant-pollinator network structure and function. Such knowledge is key to evaluate the resilience and stability of plant-pollinator communities and the services they provide in the face of increasing human disturbances.
植物-传粉者网络研究揭示了这些群落结构的重要普遍性，迅速提高了我们对这种结构潜在驱动因素的理解。然而，尽管如此，我们仍然不清楚结构网络属性的变化如何影响植物整体授粉成功率。一个关键的限制是缺乏关于网络结构属性与传粉和植物生殖成功率方面之间关系的信息。在这里，我们在两个不同的地点估计了四个植物物种网络结构指标（相互作用强度、加权度、接近中心性和专业化水平），这些指标通常用于描述它们在植物-传粉者网络中的重要性，并评估它们对花粉沉积和花粉管成功的影响。我们发现植物-传粉者专业化程度与异质花粉负载大小呈正相关，而接近中心性与花粉管成功呈负相关。我们的研究结果表明，嵌套群落中植物-传粉者专业化程度的增加（由一个或极少数一般化的昆虫物种授粉）可能导致高水平的异质花粉转移。此外，植物-传粉者网络指标对授粉成功率（花粉接收和花粉管成功）的不同影响，突出了需要整合授粉的数量（例如访问率）和质量（例如花粉传递）方面，以实现对植物-传粉者网络结构和功能之间关系的更机械理解。这种知识是评估植物-传粉者群落的弹性和稳定性以及它们在面对日益增加的人类干扰时提供的服务的关键。
