Warren J, James P
Institute of Rural Sciences, Aberystwyth University, Aberystwyth, Ceredigion, UK.
J Evol Biol. 2008 Jul;21(4):1024-9. doi: 10.1111/j.1420-9101.2008.01543.x. Epub 2008 May 6.
To answer the question whether flowers wave to attract pollinators, we determine: (1) the heritability of floral mobility; (2) whether wavy flowers attract more insects; (3) does the duration of pollination affect seed set; and (4) the relationship between seed set and floral mobility. The pollination ecology of Silene maritima was investigated. Flowers on stalks of different waviness were used to investigate the effect of floral movement on pollinator visits. There is heritable variation in both direct and indirect estimates of floral mobility. The highest insect total visitation times were associated with medium length thin stalks that were visited more frequently and by more insect species. Although mean individual visit durations were less than those of less mobile flowers, this was compensated for by increased visits. Observations of controlled pollinations show that when the visit times are low, so is seed set and therefore low and high mobility flowers might suffer from reduced fitness. Combining these observations provides a mechanism that could be driving stabilizing selection for flower stalk traits, with a trade-off applying between waving to attract pollinators and not being too mobile as to prevent effective pollination. Further evidence for stabilizing selection is provided by the relationship observed in the field between seed set and floral mobility where the highest levels of fitness was associated with intermediate levels of floral waving.
为了回答花朵是否通过摆动来吸引传粉者这一问题,我们确定了:(1)花的可动性的遗传力;(2)摆动的花朵是否吸引更多昆虫;(3)授粉持续时间是否影响结实率;以及(4)结实率与花的可动性之间的关系。对海滨蝇子草的传粉生态学进行了研究。使用不同弯曲度花茎上的花朵来研究花的运动对传粉者访花的影响。在花的可动性的直接和间接估计中均存在遗传变异。昆虫总访花次数最高与中等长度的细花茎有关,这些花茎被访花的频率更高,且有更多种类的昆虫访花。虽然平均单次访花持续时间比可动性较低的花短,但访花次数的增加弥补了这一点。人工控制授粉的观察结果表明,当访花次数较少时,结实率也较低,因此,可动性低和高的花朵可能适合度较低。综合这些观察结果,提供了一种可能推动对花茎性状进行稳定选择的机制,即在通过摆动吸引传粉者和不过于可动以防止有效授粉之间存在权衡。在野外观察到的结实率与花的可动性之间的关系为稳定选择提供了进一步的证据,其中最高的适合度水平与中等程度的花的摆动有关。