传粉细蛾与大戟科植物专性授粉的互惠共生体系

在已知的昆虫与植物所形成的专性授粉互惠共生体系中,榕树—榕小蜂、丝兰—丝兰蛾体系是经典实例,国内外学者已经从不同角度进行了大量的研究,为我们理解植物—传粉者互惠共生体系协同进化的机理和历史积累了宝贵的资料。近些年的研究发现鳞翅目细蛾科头细蛾属昆虫与大戟科植物之间也存在相似的协同进化关系。文章对国内外学者有关传粉细蛾与大戟科植物互惠共生协同进化的研究进行了整理。     

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

【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。     

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

【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。     

头细蛾专性授粉体系中区域性共生多样化研究

头细蛾属昆虫与叶下珠科植物互利共生体系中头细蛾复合体的区域性物种组成的具体情况是互利共生多样性研究模型选取的重要参考指标。本研究通过对全世界头细蛾属昆虫与叶下珠科植物协同进化体系中非一对一互利共生关系进行系统的整理,并对小果叶下珠Phyllanthus microcarpus、黑面神Breynia fruticosa、圆果算盘子Glochidion sphaerogynum、革叶算盘子Glochidion daltonii 4种植物相关的互利共生模式在不同分布区头细蛾物种成分以及种群动态进行研究。结果显示:在广西小果叶下珠居群上共生3种头细蛾,这3种头细蛾在同年的第一个世代只出现2种,在云南和海南小果叶下珠上全年只发现2种,而在广州目前饲养的头细蛾成虫更是仅有叔头细蛾1种;革叶算盘子在云南和四川有2种共生头细蛾,而在广西和海南均仅有1种;在海南和厦门黑面神与喙果黑面神共享2种头细蛾,而在广西和广东黑面神上仅发现1种头细蛾;圆果算盘子是目前发现共生头细蛾物种最复杂的寄主植物,在海南记载有4种头细蛾,但在云南圆果算盘子上仅发现优头细蛾1种。4种寄主植物相关的互利共生体系中头细蛾物种组成在不同的分布地均发生了不同程度的区域性共生多样化,甚至在同一地区的不同世代之间也存在着头细蛾物种数量的变化,这对于深入理解具有互利共生关系的物种间协同进化多样性形成机制具有重要的意义。     

小叶黑面神与小叶头细蛾互惠共生系统的种群调控机制(英文)

【目的】探索小叶黑面神Breynia vitis-idaea对小叶头细蛾Epicephala vitisidaea种群数量的调控机制。【方法】跟踪记录小叶黑面神物候及头细蛾的生物学。解剖在小叶黑面神上访花头细蛾的外生殖器,鉴定头细蛾种类。对不同时期小叶黑面神有梗和无梗的果实进行解剖,统计果实内幼虫数量、果实表面孔的数量以及果实表面产卵疤数量,计算头细蛾幼虫存活率。统计不同时期小叶黑面神有梗和无梗的果实的比例。【结果】在福建厦门小叶黑面神每年有5个花果期,相应地,为小叶黑面神传粉的头细蛾每年有5个生活世代。通过解剖,该种头细蛾被鉴定为小叶头细蛾。一头小叶头细蛾幼虫需要消耗2~4粒种子才能发育成熟。小叶黑面神有两种不同形态的果实:有梗和无梗。头细蛾幼虫在无梗果实内的存活率明显高于有梗果实,并且晚秋时期头细蛾幼虫的存活率要高于夏季。小叶黑面神无梗果实的比例在晚秋(82.04%)要高于夏季(31.53%)。【结论】本研究揭示了维持互利共生体系稳定的机制。小叶黑面神能够通过果实基部果梗的有无来调节小叶头细蛾幼虫的存活率。小叶黑面神通过季节性的调节有梗果实的比率,既有效避免了夏季种子被过度消耗的风险,又提高了头细蛾在冬季的存活率。小叶黑面神这种自身调控机制对维持小叶黑面神与小叶头细蛾互惠共生系统的稳定性起到了至关重要的作用。     

宽瓣头细蛾形态及生物学特性研究

宽瓣头细蛾Epicephala lativalvaris Li, Wang & Zhang是最近发现在黑面神Breynia fruticosa和喙果黑面神B. rostrata上专性传粉的昆虫。通过野外观察宽瓣头细蛾的访花行为、 室内饲养宽瓣头细蛾幼虫及解剖黑面神和喙果黑面神果实, 首次对其个体发育过程中各虫态的形态特征及生活习性和生活史进行了详细研究。结果表明： 宽瓣头细蛾的生活史因气候的不同而出现差异, 其在福建厦门1年发生4~5代, 有4个羽化主要高峰期, 分别为5月上旬至中旬、 6月中旬至下旬、 8月及9月下旬至10月上旬, 11月中下旬有少数成虫羽化, 12月上旬至次年4月中旬以卵或蛹越冬; 而在海南鹦哥岭1年发生6代, 无越冬现象。成虫分别主动为黑面神或喙果黑面神传粉并将卵产于子房内, 幼虫以寄主植物种子为食, 需要消耗果实内全部6粒种子才能发育成熟, 但每个种群内留有20.37%~77.63%完好的果实, 以维持互利关系的稳定。两种植物的结实率近似, 但宽瓣头细蛾对喙果黑面神的果实危害率是黑面神的2.05倍。结果说明, 在宽瓣头细蛾 黑面神和喙果黑面神专性传粉互利共生关系中, 两种寄主植物所获得的利益近似, 但喙果黑面神为宽瓣头细蛾提供了更多的回报。研究结果为头细蛾属其他种类生物学特性的了解提供了借鉴, 并为探讨宽瓣头细蛾 黑面神和喙果黑面神专性传粉互利共生关系稳定性的维持机制提供了基本依据。     

优头细蛾(鳞翅目:细蛾科)的生物学特性及生存对策研究

【目的】探探索优头细蛾Epicephala sp.适应圆果算盘子Glochidion sphaerogynum特点而采取的生存对策,对揭示圆果算盘子与优头细蛾协同进化关系有重要的意义。【方法】本文通过对圆果算盘子物候、优头细蛾生活史、成虫活动规律以及圆果算盘子种子被幼虫蛀食情况这几方面的研究对优头细蛾适应性生存对策进行了探讨。【结果】圆果算盘子在整个算盘子属中呈现了一些与众不同的特点,特别体现在物候和雌花形态这两方面。在海南鹦哥岭,圆果算盘子每年只有一个花期,优头细蛾每年相应只有一个世代。优头细蛾是圆果算盘子的专性寄生者,承担着为圆果算盘子传粉的任务。头细蛾幼虫出果率为56.33%,完整种子保存率为56.58%,每头幼虫平均消耗4.53粒种子。【结论】优头细蛾通过以卵越夏对策,能够实现成虫发生期与圆果算盘子花期精准匹配。成虫选择了在雌花顶端小孔插入产卵器的产卵方式,并形成了与之相应的雌花选择和先产卵后传粉的生存对策,这样的产卵对策是适应圆果算盘子雌花形态的表现,同时对提高传粉效率、限制种子过度开采等方面体现了积极作用。     

杨金纹细蛾的生物学

杨金纹细蛾(Lithocolletis sp.)属鳞翅目、细蛾科(Gracilariidae)。近年来在河北省中部、中南部地区和北京市大量发生,很多地方苗圃和幼林株被害率高达百分之百,我校苗圃内毛白杨平均每个叶片有虫斑1—45个,多数10—27个(见图1)。叶片受害后干脆、皱缩、逐渐变黄早落。形成光杆,从而降低苗木质量。 此虫在我国尚无报道。作者自1976年冬至     

中国头细蛾属昆虫(鳞翅目,细蛾科)与大戟科植物互利共生关系研究进展

细蛾科头细蛾属昆虫与大戟科算盘子属、叶下珠属和黑面神属植物互利共生关系的发现为研究昆虫与植物协同演化过程提供了一个全新的模式。目前,国内对头细蛾与大戟科植物的互利共生关系了解和研究都很少。本文介绍了头细蛾的分类、生物学和形态适应;大戟科相关5属植物(算盘子属、叶下珠属、黑面神属、白饭树属和守宫木属)的生物地理学,开花生物学,花的结构与传粉系统的关系;寄主植物与传粉者的对应关系;互利共生关系的维持机制等。研究表明中国有丰富的头细蛾与大戟科植物资源,开展其互利共生关系的研究有重要科学意义。很多新的、复杂的头细蛾与大戟科植物的生态关系和大量的头细蛾种类有待我们去发现和研究。     

三室算盘子寄主上弯头细蛾的生物学特性及花气味成分分析

【目的】为了从生物学和化学生态学角度探讨弯头细蛾Epicephala ancylopa和寄主三室算盘子Glochidion sp.间专性传粉的互利共生关系稳定性。【方法】本研究在野外观察和室内实验的基础上,对专性传粉育幼互利共生体系中三室算盘子、弯头细蛾生物学特性进行详细研究,探究互利共生双方利益得失;用动态顶空吸附法分别收集三室算盘子雄花和雌花气味物质,运用气相色谱-质谱联用技术(GC-MS)分析并鉴定其有效成分,用峰面积归一化与内标法定性定量;最后通过主成分分析法比较雄花和雌花之间气味化学成分的差异性。【结果】弯头细蛾在云南省普洱太阳河国家森林公园每年有1个世代,成虫和幼虫的活动时间分别在3-4月和8-10月。三室算盘子结实率为44.20%,被蛀食率为69.94%,平均每头幼虫消耗2.55枚种子来满足自身生长发育,寄主植物留有83.06%完好的种子,以维持互利共生关系的稳定。三室算盘子雌雄花气味中共鉴定出24种挥发物,主要以单萜类和倍半萜类物质为主,其中(Z)-罗勒烯和β-榄香烯两种萜类物质含量最高(分别为47.11%和22.72%),推测其是吸引弯头细蛾传粉的主要气味成分;雄花和雌花之间气味化学成分存在明显的差异,具有两性异型性。【结论】弯头细蛾通过以卵越夏和以蛹越冬对策,实现成虫发生期与三室算盘子花期的精准匹配。弯头细蛾成虫白天静伏,傍晚开始活动,三室算盘子花的气味物质也只在晚上才明显释放,且雌雄花气味化学成分的两性异型性有利于弯头细蛾辨别雌雄花,以完成采集花粉与传粉行为。该研究结果为头细蛾属昆虫与算盘子属植物专性传粉互利共生关系稳定性的维持机制提供了新的依据,也为深入开展通过触角电生理检测和生物行为实验来筛选吸引传粉头细蛾的活性物质提供了理论依据。     

Assessment of the diversity and species specificity of the mutualistic association between Epicephala moths and Glochidion trees

The obligate mutualisms between flowering plants and their seed-parasitic pollinators constitute fascinating examples of interspecific mutualisms, which are often characterized by high levels of species diversity and reciprocal species specificity. The diversification in these mutualisms has been thought to occur through simultaneous speciation of the partners, mediated by tight reciprocal adaptation; however, recent studies cast doubt over this general view. In this study, we examine the diversity and species specificity of Epicephala moths (Gracillariidae) that pollinate Glochidion trees (Phyllanthaceae), using analysis of mitochondrial and nuclear gene sequences. Phylogenetic analysis of Epicephala moths associated with five Glochidion species in Japan and Taiwan reveal six genetically isolated species that are also distinguishable by male genital morphology: (i) two species specific to single host species (G. acuminatum and G. zeylanicum, respectively); (ii) two species that coexist on G. lanceolatum; and (iii) two species that share two, closely-related parapatric hosts (G. obovatum and G. rubrum). Statistical analysis shows that the two species associated with G. lanceolatum are not sister species, indicating the colonization of novel Glochidion host in at least one lineage. Behavioural observations suggest that all six species possess the actively-pollinating habit, thus none of the studied species has become a nonmutualistic 'cheater' that exploits the benefit resulting from pollination by other species. Our results parallel recent findings in ecologically similar associations, namely the fig-fig wasp and yucca-yucca moth mutualisms, and contribute to a more general understanding of the factors that determine ecological and evolutionary outcomes in these mutualisms.     

Obligate pollination mutualism in Breynia (Phyllanthaceae): further documentation of pollination mutualism involving Epicephala moths (Gracillariidae)

This paper reports obligate seed-parasitic pollination mutualisms in Breynia vitis-idea and B. fruticosa (Phyllanthaceae). The genus Breynia is closely related to Glochidion and Gomphidium (a subgenus of Phyllanthus), in which pollination by species-specific, seed-parasitic Epicephala moths (Gracillariidae) have been previously reported. At night, female Epicephala moths carrying numerous pollen grains on their proboscises visited female flowers of B. vitis-idea, actively pollinated flowers, and each subsequently laid an egg. Examination of field-collected flowers indicated that pollinated flowers of B. vitis-idea and B. fruticosa almost invariably had Epicephala eggs, suggesting that these moths are the primary pollinators of the two species. Single Epicephala larvae consumed a fraction of seeds within developing fruit in B. vitis-idea and all seeds in B. fruticosa. However, some of the fruits were left untouched, and many of these had indication of moth oviposition, suggesting that egg/larval mortality of Epicephala moths is an important factor assuring seed set in these plants. The overall similarity of the specialized floral structure among Breynia species may indicate that this pollination system is fairly widespread within the genus.     

Variation in the costs and benefits of mutualism: the interaction between yuccas and yucca moths

Summary Yucca moths are both obligate pollinators and obligate seed predators of yuccas. I measured the costs and net benefits per fruit arising for eight species of yuccas from their interaction with the yucca moth Tegeticula yuccasella. Yucca moths decrease the production of viable seeds as a result of oviposition by adults and feeding by larvae. Oviposition through the ovary wall caused 2.3–28.6% of ovules per locule to fail to develop, leaving fruit with constrictions, and overall, 0.6–6.6% of ovules per fruit were lost to oviposition by yucca moths. Individual yucca moth larvae ate 18.0–43.6% of the ovules in a locule. However, because of the number of larvae per fruit and the proportion of viable seeds, yucca moth larvae consumed only 0.0–13.6% of potentially viable ovules per fruit. Given both oviposition and feeding effects, yucca moths decreased viable seed production by 0.6–19.5%. The ratio of costs to (gross) benefits varied from 0% to 30%, indicating that up to 30% of the benefits available to yuccas are subsequently lost to yucca moths. The costs are both lower and more variable than in a similar pollinator-seed predator mutualism involving figs and fig wasps.There were differences between species of yuccas in the costs of associating with yucca moths. Yuccas with baccate fruit experienced lower costs than species with capsular fruit. There were also differences in costs between populations within species and high variation in costs between fruit within populations. High variability was the result of no yucca moth larvae being present in over 50% of the fruit in some populations, while other fruit produced up to 24 larvae. I present hypotheses explaining both the absence and high numbers of larvae per fruit.     

Diversity and species-specificity of brood pollination of leafflower trees (Phyllanthaceae: Glochidion) by leafflower moths (Lepidoptera: Epicephala) in tropical Southeast Asia (Cambodia)

Glochidion (Phyllanthaceae; leafflower trees) is a genus of trees which is widely reported to be pollinated by leafflower moths (Gracillariidae: Epicephala) in temperate and subtropical Asia, Australia, and the Pacific islands. However, the pollination ecology of Glochidion is not well described from tropical Asia, the region where it is most species-rich at both local (≤9 spp.) and regional (~200 spp.) scales. Here we report investigations of pollination biology and species-specificity of five Glochidion species in tropical Southeast Asia (Cambodia). Through nocturnal observations and fruit dissections, we find that at least three and likely five Glochidion species in Cambodia are pollinated by seed-parasitic leafflower moths. We find no evidence that any of these leafflower moths are non-mutualistic parasites, despite known examples of such parasites of this mutualism elsewhere in Asia. While the presence of a single larva in a fruit results in only a fraction of seeds being consumed, the presence of more than one larva per fruit—a frequent occurrence in some species—can result in almost all seeds within the fruit being infested. Multilocus phylogenetic analysis indicates that there are five different minimally monophyletic leafflower moth clades, each of which pollinates a unique Glochidion host species. Our results indicate that in its center of diversity in tropical Asia this system is an obligate pollination mutualism as previously described at the global margins of its distribution. These findings provide insights into the processes that generate and maintain biodiversity and maintain mutualism stability in plant–insect interactions in this biodiversity hotspot.     

Limiting cheaters in mutualism: evidence from hybridization between mutualist and cheater yucca moths

Mutualisms are balanced antagonistic interactions where both species gain a net benefit. Because mutualisms generate resources, they can be exploited by individuals that reap the benefits of the interaction without paying any cost. The presence of such 'cheaters' may have important consequences, yet we are only beginning to understand how cheaters evolve from mutualists and how their evolution may be curtailed within mutualistic lineages. The yucca-yucca moth pollination mutualism is an excellent model in this context as there have been two origins of cheating from within the yucca moth lineage. We used nuclear and mitochondrial DNA markers to examine genetic structure in a moth population where a cheater species is parapatric with a resident pollinator. The results revealed extensive hybridization between pollinators and cheaters. Hybrids were genetically intermediate to parental populations, even though all individuals in this population had a pollinator phenotype. The results suggest that mutualisms can be stable in the face of introgression of cheater genes and that the ability of cheaters to invade a given mutualism may be more limited than previously appreciated.     

Regulation of the mutualism between yuccas and yucca moths: intrinsic and extrinsic factors affecting flower retention

Yuccas initiate far more flowers than they can mature as fruit, thereby providing opportunities for them to mature flowers of the highest quality. Flower quality in yuccas has both intrinsic and extrinsic components. Intrinsic components relate to flower morphology and inflorescence architecture. Yucca moths (Tegeticula spp., Incurvariidae), the sole pollinators and primary seed predators of most yuccas (Yucca spp., Agavaceae), mediate extrinsic components of flower quality through their ovipositions in flowers, and the quantity and quality of pollen that they transfer. In addition, intrinsic and extrinsic components interact as a function of flowering phenology and moth activity within inflorescences.
We investigated selective abscission of flowers in Y. kanabensis with respect to various combinations of intrinsic and extrinsic factors. First, we considered the effect of high and low pollen loads delivered to different subsets of flowers and in different presentation orders. In the absence of moth ovipositions, Y. kanabensis is sensitive to the amount of pollen that moths deliver and tends to retain high pollen flowers, even when all flowers receive sufficient pollen for full fertilization. However, pollen delivery sequence and the position of flowers with an inflorescence modify this high pollen effect. We then considered the interplay between high and low pollen combined with moth ovipositions and found that the number of ovipositions dominated the pollen effect. Finally, we considered number of ovipositions in conjunction with different flowers in the blooming sequence while controlling pollen levels and found that the clear effect of ovipositions on flower fate can be tempered by where the flower is in the blooming sequence.
These results have implications for the regulation of the mutualism between yuccas and yucca moths, indicating that yuccas are capable of regulating costs, retaining flowers of relative high quality and selectively abscising the rest. Yucca sensitivity to several intrinsic and extrinsic factors allows the plant to respond flexibly to the pollination environment and several species of moths.