-
传粉过程是研究花部特征和传粉者关系的纽带,进而也为研究花部特征进化提供了契机[1]。传粉昆虫往往会对某一色系的花产生偏爱[2,3],花色也成为植物吸引传粉者重要“广告特征”之一[4,5]。由于传粉者不能在距离花朵0.4 m以外分辨出是否有报酬,因此开花植物往往通过花色近距离吸引传粉者,即传粉者对颜色的偏好则在近距离内发生选择性作用[5]。盗蜜是指访花者直接在蜜距或是花冠上打洞,不进行授粉仅取食花蜜的行为,是影响植物与传粉者互利共生关系关键的生物因素之一[6,7]。在动植物的相互关系中,盗蜜被认为是一种不同于普通传粉者的不正常的访花行为,盗蜜者除了作为似盗蜜传粉的正效应之外,还可能改变对正常传粉者的访花行为[8]。一些研究结果显示,盗蜜对植物的结实可能不会产生影响,但也有可能会通过影响传粉者行为而影响传粉者介导的结实[9]。总之,盗蜜如何通过影响植物与传粉者的互利共生关系,最终影响植物的适合度与进化仍不明了。通过人工操纵法隔离盗蜜者作为对照,可针对性评价盗蜜的生态学后果,有利于更深入地研究多物种间的相互作用和协同进化。用纱网袋套住植物的花冠或蜜距隔离盗蜜者时,纱网袋颜色可能会干扰传粉者正常访问,因为传粉者往往偏爱某种颜色的花[2,3]。因而,筛选出一种对传粉者干扰最小的纱网袋颜色成为最急需解决的问题。研究盗蜜对传粉者访花行为的影响,若在传粉者访问的高峰时间段进行观测,效果更明显,因而传粉者一天中的访花节律也值得进一步探讨。研究发现,传粉者一天中的访问节律与环境因子以及植物的花部特征、花蜜产量等密切相关[10-12],每个时间段的花蜜体积、糖浓度变化尤为明显[13],这意味着传粉者在不同时间的访花频率存在一定差异。那么,找到一天之中传粉者访花频率最高的时段,也可为有效的人工授粉时间提供依据。若能有效地提高植物的授粉概率,可为促进植物的生殖成功提供参考。
凤仙花属(Impatiens L.)是被子植物中的一个大属,隶属于凤仙花科(Balsaminaceae),全世界共有900多种,中国作为世界凤仙花属的分布中心之一,拥有该属240多个物种[14]。凤仙花属家族庞大,花朵娇嫩多汁,花部结构复杂,且具有非常广泛的多样性和各个类型的传粉者,是比较理想的研究植物分类学的材料,也是众多传粉生物学家关注的热点类群[15-17]。拥有长花冠筒或是蜜距的植物容易被盗蜜,在该属植物中,长蜜距花被盗蜜的现象十分普遍[15,18,19]。研究盗蜜通过影响传粉者行为而介导该属植物的生殖成功对于理解多物种的相互作用机制及其后果具有重要的意义。
因此,选择了4种颜色(黑、白、红、绿)纱网袋套蜜距,以不套蜜距作为对照,在一天中6个时间段,分别观测红雉凤仙花传粉者的访花频率和单花停留时间,以筛选出对传粉者访花行为影响最小的纱网袋颜色和最佳的访问时间段,便于后续开展盗蜜的生态学研究。
Effect of Gauze Bag Color on Visiting Behaviors of Impatiens oxyanthera Pollinators in Different Time Periods
doi: 10.12172/202010150003
- Received Date: 2020-10-15
- Available Online: 2020-12-22
- Publish Date: 2021-02-04
-
Key words:
- Gauze bag color /
- Visiting rhythm /
- Impatiens oxyanthera /
- Visiting frequency of pollinators /
- Visiting duration time of pollinators
Abstract: The impacts of nectar robbing on the reproductive success of plants is still controversial. The ecological consequences and mechanisms of nectar robbing can be effectively studied by using gauze bags to isolate nectar robbers and create a control treatment without nectar robbers. However, gauze bag color may interfere with pollinators because pollinators prefer flowers with a certain color. In this study, in order to screen the color of gauze bags with the least interference with pollinators, four kinds of gauze bags with different colors (black, white, red and green) were designed for bagging nectar spur. Natural nectar spurs without bagging were used as the control treatment to compare the differences in visiting frequency of pollinators and visiting duration time on single flower of Impatiens oxyanthera among five treatments in the six time periods in a day. The results showed that: (1) The visiting frequency of pollinators was significantly different among five treatments. The visiting frequency of pollinators to flowers with white gauze bag was closed to that of the control which was the highest, and the visiting frequency of black gauze bag treatment was the lowest, which was significantly different from the other four treatments. The gauze bag color had no significant effect on visiting duration time of pollinators on single flower. (2) The observation time period had a significantly effect on the visiting frequency and visiting duration time of pollinators on single flower. The most frequent visits occurred from 14:30 to 15:00 and the longest visiting duration time of pollinators was from 9:30 to 9:50 am. The results indicated that when isolating the nectar robbers, the white gauze bag had less interference on the pollinator's visiting behaviors, while the black one had the greatest interference. This study provided an important method reference for researching the effects of nectar robbing on plant-pollinator mutualisms through isolating nectar robber with gauze bag.