谁是腊梅的主要传粉者:昆虫行为与传粉作用

Who are the major pollinators of Chimonanthus praecox(Calycanthaceae):insect behaviors and potential pollination roles

访花昆虫不同的访花与飞行行为导致其访花频率不同,进而对植物传粉产生不同的影响。意大利蜜蜂(Apis mellifera ligustica)、苍蝇和食蚜蝇是腊梅(Chimonanthus praecox)最常见的访花类群(或种类),但是它们的访花行为却有很大不同。意大利蜜蜂主要以快速飞行为主,偶见爬行,苍蝇访花时主要以快速飞行、爬行和跳跃为主,而食蚜蝇以长时间单花访问和悬空飞行以及间歇性休息为主。根据访花类群(或种类)在一朵花上的访花时间和花间飞行时间进行推算,每只意大利蜜蜂、苍蝇和食蚜蝇每分钟分别可以访问4.57、2.65和0.53朵花。结合每种(类)昆虫的访花数量推算出意大利蜜蜂、苍蝇和食蚜蝇每分钟分别可以访问498.19、1,089.74和99.78朵花。传粉效力(相同条件下单位时间内相同数目访花者能够授粉的花朵数)实验结果证明苍蝇和意大利蜜蜂分别是93%、100%(n=30),而食蚜蝇只有13%(n=30)。苍蝇和意大利蜜蜂可携带大量花粉且具有很高的传粉效力,因此,访花速度的快慢是二者访花能力强弱的主要限制因素。由此,我们认为苍蝇可能是腊梅最主要的传粉者,意大利蜜蜂次之(数量偏少),食蚜蝇再次(访花与飞行行为的影响以及访花效力较低是限制其访花能力的主要因素)。

Variable insect behaviors may result in different fower visiting frequencies, which may result in diverse impacts on plant pollination. Although flies, hoverflies, and Italian bees （Apis mellifera ligustica） were the most common visitors of Chimonanthus praecox, these insect groups had disparate visiting behav- iors. Flies traveled quickly, and crawled or jumped between fowers. Italian bees also flew quickly or occasionally crawled between flowers. In contrast, hoverflies generally spent a majority of time foraging on a given flower. Based on the average foraging time and inter-floral flight time, one Italian bee could visit 4.57 flowers per minute, whereas individual bees and hoverflies could visit 2.65 and 0.53 flowers on average, re- spectively. After incorporating the total number of individuals for each insect group, we extrapolated the vis- iting rates of Italian bees, flies and hoverflies as 498.19, 1,089.74 and 99.78 flowers per minute, respectively. Flies and Italian bees had higher pollination effectiveness （number of pollinated flowers by the same number of visitors in a given time interval under the same condition）, with estimates of 93% and 100% （n = 30）, re- spectively, while only 13% （n = 30） for hoverflies. If we consider the pollen load ability and pollination ef- fectiveness for Italian bees and flies, visiting rate may be the main limiting factor for their potential in polli- nating flowers. Thus following these conclusions, flies are the major pollinators of C. praecox, followed by Italian bees （pollination role was limited by their low number） and hoverflies （limited by their foraging and hovering behaviors and lower pollination effectiveness）.