Abstract As agriculture expands to meet the needs of a growing global population, natural ecosystems are threatened by deforestation and habitat fragmentation. Tropical agroforestry systems offer a sustainable alternative to traditional agriculture by providing food for production while also supporting biodiversity and ecosystem services. Previous studies have shown that these systems may even improve crop pollination, but the mechanisms of how these improvements occur are still poorly understood. Using coffee as a focal crop, we explored how microclimatic conditions affected nectar traits (sugar and caffeine concentration) important for pollinator visitation. We also studied how microclimate, floral traits, floral availability at the coffee plant level, availability of floral resources provided by other plant species in the agroecosystem (“neighborhood floral availability”), and the presence of other bees affected the amount of time bees spent foraging on coffee flowers and the proportion of coffee pollen carried on their bodies. We explored these factors using the two dominant coffee species farmed on Puerto Rico, Coffea canephora and C. arabica, under sun and shade management. We found that high nectar sugar concentration and temperature were important predictors of short floral visits (

中文翻译：

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花卉资源和小气候对农业生态系统中传粉媒介访问的影响

摘要 随着农业扩张以满足不断增长的全球人口的需求，自然生态系统受到森林砍伐和栖息地破碎化的威胁。热带农林业系统通过为生产提供粮食，同时还支持生物多样性和生态系统服务，为传统农业提供了可持续的替代方案。先前的研究表明，这些系统甚至可以改善作物授粉，但这些改善如何发生的机制仍然知之甚少。使用咖啡作为重点作物，我们探索了小气候条件如何影响对传粉媒介访问很重要的花蜜特性（糖和咖啡因浓度）。我们还研究了咖啡植物水平的小气候、花卉特征、花卉可用性、农业生态系统中其他植物物种提供的花卉资源的可用性（“邻里花卉可用性”），以及其他蜜蜂的存在影响了蜜蜂在咖啡花上觅食的时间以及它们身上携带的咖啡花粉的比例。我们使用波多黎各种植的两种主要咖啡品种 Coffea canephora 和 C. arabica 在阳光和遮荫管理下探索了这些因素。我们发现高浓度的花蜜糖分和温度是短暂花期的重要预测因素。在阳光和遮荫管理下。我们发现高浓度的花蜜糖分和温度是短暂花期的重要预测因素。在阳光和遮荫管理下。我们发现高浓度的花蜜糖分和温度是短暂花期的重要预测因素。