暖化對蜜蜂授粉行為及蜜蜂幼蟲發育的影響

Abstract

授粉者提供重要的生態系統服務，其中全世界有三分之一以上的農作物依賴動物授粉。研究顯示，暖化導致授粉者活動和植物開花時間發生物候變化，這可能會改變當前的植物-授粉者交互作用。但是，暖化在一天的尺度中對植物-授粉者交互作用的影響尚不清楚。本研究利用西洋蜂（Apis mellifera）擔任授粉者，探討暖化是否影響（1）一天中蜜蜂覓食的模式、（2）一天中植物開花的時間、（3）蜜蜂採集花粉的組成，以及後續蜜蜂幼蟲的發育情況。我們透過野外實驗加熱蜂箱，以研究暖化對蜜蜂覓食行為的影響，並利用分子鑑定確認蜜蜂花粉種類後，選擇主要的植物物種來探討暖化對一天中開花時間的影響。最後，我們利用研究室飼養實驗比較暖化下的花粉組成是否會影響蜜蜂幼蟲的發育。實驗結果顯示，暖化促進並提早一天中蜜蜂的覓食活動和Bidens pilosa的開花時間，增加B. pilosa在蜜蜂花粉中的比例，並促進了幼蟲的生長。綜合以上結果，本研究顯示暖化可以通過短期的時間尺度影響授粉者的行為和植物開花時間，進而改變授粉者與植物間的交互作用以及授粉者的發育。

Pollinators provide critical ecosystem services, such that more than one third of crops depend on animal pollination worldwide. Studies have shown that climate warming leads to phenology shifts in pollinator foraging and plant flowering at seasonal scales, which could interrupt current plant-pollinator interactions. However, warming impact on within-day patterns in plant-pollinator interactions remains unclear. Using honey bee (Apis mellifera) as a model pollinator, this study aims to examine if warming affects (1) the within-day pattern in honey bee foraging, (2) the within-day pattern of plant flowering onset (i.e., flowering time of the day), and (3) the composition of pollen collected by honey bees, which may influence honey bee larval development. To do so, we experimentally heated up beehives to investigate the effect of warming on honey bee foraging behavior. After identifying the bee pollen, we selected a key plant species (Bidens pilosa var. radiata) and examined warming impact on its onset of flowering. Furthermore, we investigated if any warming-induced changes in pollen composition affect larval development. Our results showed that warming advanced the within-day foraging activity of honey bees and flowering onset of B. pilosa, which would lead to an increase of B. pilosa in bee pollen composition and better bee larval development. Together, this study suggests important but overlooked mechanisms for climate change impact on plant-pollinator interactions: warming can affect the within-day patterns in pollinator behavior and plant flowering onsets, thus indirectly affecting pollinator performance.