叶下珠头细蛾与小果叶下珠互利共生的研究-生物学及系统稳定性
Mutualism between Epicephala sp. and Phyllanthus microcarpus — Biology and mutualistic stability
杨晓飞** 李后魂***
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DOI：10.7679/j.issn.2095-1353.2015.018
作者单位：南开大学生命科学学院，天津 300071
中文关键词：
英文关键词：Phyllanthaceae, Phyllanthus, Lepidoptera, Epicephala, biology, mutualistic stability
中文摘要： 【目的】 为了确定小果叶下珠Phyllanthus microcarpus与叶下珠头细蛾Epicephala sp.之间专性互利共生系统稳定性的增强是否主要通过彼此之间相互遏制对方对自身进行过度开采。【方法】 通过对小果叶下珠上共生的叶下珠头细蛾形态及生物学的研究，记述了叶下珠头细蛾专性寄生寄主植物时的行为特性及共生双方利益得失。【结果】 叶下珠头细蛾在广西一年两代，成虫的羽化数量与寄主植物雌雄花总数峰值变化同步；幼虫对小果叶下珠果实的寄生率为96%，单个果实内幼虫寄生数量＞1，但平均每个果实内被取食的种子为56.9%，叶下珠头细蛾低龄幼虫相对较高的死亡率限制了其对寄主种子的过度取食；果实内种子的适度保留和低龄幼虫的高死亡率是小果叶下珠-叶下珠头细蛾互利共生体系维持稳定的关键因素。【结论】 小果叶下珠的表型性状出现了趋异性进化，叶下珠头细蛾与不同表型的小果叶下珠均有互利共生关系。因此，对叶下珠头细蛾形态及生物学进行详细研究有助于深入了解小果叶下珠与头细蛾共生体系物种组成多样性及进化生物学，并为探讨大戟科植物同头细蛾属昆虫协同互利共生多样性形成原因提供依据。
英文摘要： [Objectives] To determine whether the mutualistic relationship between Phyllanthus microcarpus and Epicephala sp. involves one partner avoiding overexploitation of the other. [Methods] Based on studies of morphology and biology of Epicephala sp. that pollinate P. microcarpus exclusively, we clarified the behavioral traits of Epicephala sp. that have developed in response to their specific host and the benefits that each species has obtained from their mutualistic relationship. [Results] The results show that the lifespan of Epicephala sp. is six months with two generations per year. Changes in the number of adults synchronize with changes in the total number of the female and male flowers. The parasitism rate was 96%, and the number of larvae per fruit was above 1. However, only 56.9% of seeds were consumed per fruit and a high death rate of young instar larvae limited seeds from being overexploited. Moderate seed predation and the high death rate of young instar larvae appear to be the key factors maintaining the mutualistic relationship between these species. [Conclusion] P. microcarpus includes two phenotypic populations, both of which are mutualistic hosts of Epicephala sp. Thus, further morphological and biological studies of Epicephala sp. can contribute to understanding the evolutionary mechanisms underlying Epicephala sp.-P. microcarpus mutualism. This research provides a reference for further investigation of the mutualistic biodiversity between Epicephala and plants of the Phyllantheae (Euphorbiaceae).