Jones Kristina N, Reithel Jennifer S, Irwin Rebecca E
Rocky Mountain Biological Laboratory, Box 519, Crested Butte, Colorado, CO 81224, USA and Department of Biology, Middlebury College, Middlebury, VT 0575, USA, , , , , , US.
Oecologia. 1998 Nov;117(1-2):161-168. doi: 10.1007/s004420050644.
Pollinator behavior influences plant reproduction in many ways. A traditional measure of pollination, the number of visits received, may be a poor predictor of plant reproductive success, particularly when there are trade-offs between visit quantity and components of visit quality. For example, the duration of pollinator visits may be negatively correlated with the number of visits received by a flower. We tested for a trade-off between the number of bumblebee visits and the duration of those visits in an experimental population of snapdragons (Antirrhinummajus: Scrophulariaceae). The duration of a bumblebee visit to a flower increased significantly with the time interval since the flower had last been visited. Over the lifetime of a flower the correlation between the total number and average duration of visits received by a flower was weakly negative. However, at the whole-plant level the correlation was positive: plants whose flowers received more visits also received visits of longer duration. Factors affecting the relationship between quantity and duration of pollinator visits to flowers also were investigated. Two factors weakened the negative dependence of average visit duration on number of visits received by individual snapdragon flowers: (1) the correlation between the total number of visits to a flower and the average interval between visits was only -0.53, as visits to individual flowers were not very evenly spaced over time, and (2) newly opened flowers received fewer and shorter visits than older flowers. Comparing whole plants, nectar production per flower varied dramatically across individuals, a probable explanation for the positive correlation between visit number and average duration per flower observed at the plant level. The potential for a trade-off between these two components of pollinator service exists when visit duration depends on reward quantity; whether the trade-off is realized will depend on variation in nectar production and on whether pollinators forage systematically.
传粉者行为在许多方面影响植物繁殖。一种传统的授粉衡量指标，即接受访问的次数，可能并不能很好地预测植物的繁殖成功率，尤其是当访问数量和访问质量的各个组成部分之间存在权衡时。例如，传粉者访问的持续时间可能与一朵花接受的访问次数呈负相关。我们在一个金鱼草（Antirrhinum majus：玄参科）实验种群中测试了大黄蜂访问次数与这些访问持续时间之间的权衡。大黄蜂对一朵花的访问持续时间随着自该花上次被访问以来的时间间隔而显著增加。在一朵花的生命周期内，一朵花接受的访问总数与平均访问持续时间之间的相关性呈弱负相关。然而，在整株植物水平上，这种相关性是正的：其花朵接受更多访问的植物也接受持续时间更长的访问。我们还研究了影响传粉者对花朵访问数量和持续时间之间关系的因素。有两个因素削弱了单个金鱼草花朵平均访问持续时间对接受访问次数的负相关性：（1）一朵花的访问总数与访问平均间隔之间的相关性仅为 -0.53，因为对单个花朵的访问在时间上分布不太均匀，以及（2）新开的花比老花接受的访问次数更少且持续时间更短。比较整株植物时，每朵花的花蜜产量在个体间差异很大，这可能是在植物水平上观察到访问次数与每朵花平均持续时间之间正相关的一个解释。当访问持续时间取决于奖励数量时，传粉者服务的这两个组成部分之间存在权衡的可能性；这种权衡是否会实现将取决于花蜜产量的变化以及传粉者是否进行系统觅食。
