Leland Russell F, Louda Svata M
School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE 68588-0118, USA.
Oecologia. 2004 May;139(4):525-34. doi: 10.1007/s00442-004-1543-1. Epub 2004 Apr 1.
Phenological synchrony of a consumer population with its resource populations is expected to affect interaction intensity. We quantified phenological variation and synchrony of populations of an invasive Eurasian flower head weevil, Rhinocyllus conicus, that consumes florets, ovules, and seeds of developing flower heads of a native North American thistle, Cirsium canescens, in Sand Hills prairie in Nebraska, USA. Variation in timing of adult activity among weevil populations was larger than variation in timing of flower head development among C. canescens populations, and it drove the observed variation in the phenological synchrony between weevil and host plant populations. Furthermore, the degree of phenological synchrony between populations was significant in explaining variation in weevil egg load on the newly acquired host plant. Because population growth of C. canescens is limited by predispersal seed losses to floral herbivores, variation in the synchrony of herbivore and plant flowering will affect the density of the plant population. These results provide strong quantitative support for the hypothesis that the synchrony of insect activity with plant resources can determine the magnitude of impact of floral herbivores on their host plant populations.
消费者种群与其资源种群的物候同步性预计会影响相互作用强度。我们对一种入侵性的欧亚花头象鼻虫（Rhinocyllus conicus）种群的物候变化和同步性进行了量化，这种象鼻虫以美国内布拉斯加州沙丘草原上一种本土北美蓟（Cirsium canescens）发育中的花头的小花、胚珠和种子为食。象鼻虫种群中成年个体活动时间的变化大于C. canescens种群中花头发育时间的变化，并且它驱动了象鼻虫与寄主植物种群之间物候同步性的观测变化。此外，种群之间的物候同步程度在解释新获取寄主植物上象鼻虫卵负载的变化方面具有显著意义。由于C. canescens的种群增长受到种子在扩散前被食草动物消耗的限制，食草动物与植物开花同步性的变化将影响植物种群的密度。这些结果为昆虫活动与植物资源的同步性能够决定食花食草动物对其寄主植物种群影响程度这一假说提供了有力的定量支持。
