韦氏缩腹榕小蜂的产卵行为

通过对聚果榕上一种非传粉榕小蜂———韦氏缩腹小蜂ApocryptawestwoodiGrandi的产卵行为的详细观察 ,发现该小蜂的产卵行为与具有可伸缩的腹节这种奇特的腹部结构高度相关。该小蜂的产卵过程主要分为 3个阶段 :( 1 )寻找产卵位置 ,小蜂在果面快速搜索 ,以触角或口器触须感受产卵位点 ;( 2 )刺壁 ,小蜂将产卵针垂直于果面 ,刺入果壁 ,进入果腔 ;( 3 )产卵与拉出产卵针。通过与Ansari对于韦氏缩腹小蜂的产卵行为的描述进行比较 ,发现有如下不同之处 :( 1 )在产卵针刚刺入果面时 ,伸长的腹部末端超过头 ,整个伸长的腹部几乎与果面平行 ;( 2 )后足具有下拉产卵鞘的行为 ,并且后足除下拉产卵鞘时与果面分离外 ,均抓住果面 ;( 3 )产卵针不需要产卵鞘支撑时 ,产卵鞘与产卵针分离。     

Resource allocation: a conflict in the fig/fig wasp mutualism?

Conflicts of interest are omnipresent between mutualist species. In the monoecious fig/pollinator wasp mutualism, each female flower produces either a seed or a pollinator offspring (which has fed on a single seed). Pollen from a syconium (i.e. fig, a closed urn-shaped inflorescence) is only dispersed by female pollinator offspring born in this syconium. Thus the fig tree is selected to produce both seed and pollinator offspring whereas for the pollinator there is no short term advantage in seed production. Using controlled pollination experiments (pollen injection, and foundress introduction), we show that 1) The relative proportion of seeds and pollinator offspring produced (i.e., the effective allocation between female and male function) depends mainly on the number of foundresses that entered the syconium. 2) Many female flowers within every syconium mature neither a seed nor a wasp (from 25% to 33%). 3) All the female flowers within a syconium that are not vacant at maturity have the potential to produce a seed, and at least 80% of them can produce a pollinator. Several hypotheses concerning mechanisms that govern the partitioning between seed and wasp production are discussed, and their evolutionary consequences are considered.     

Germination ecology of drupelets of the fig (Ficus carica L.)

Abiotic and biotic factors and their effects on germination of fig drupelets were studied. The drupelets germinated between 10^oC and 30^oC.Constant humidity was necessary for germination and frequent drying out of the substrate was unfavourable. Total darkness for the whole duration of the experiments had a slighly negative effect on germination. The fastest germination occurred at constant humidity and an alternating temperature of 20/30^oC with exposure to light for 8 hours (at the higher temperature) and to darkness for 16 hours (at the lower temperature).Natural or artificial removal of drupelets from the syconium guaranteed a high germination percentage, whereas no germination occurred in drupelets left inside the syconium. Hence birds and mammals act as dispersal agents and mediators of germination. As they eat pieces of fig syconium, they free the drupelets from the flesh, eliminating the effect of inhibitors and/or microenvironments with high osmotic pressure inside the syconium. These findings support the hypothesis that germination occurs in autumn or spring depending on the climatic zone in which the species grows.     

The pollination of Ficus vogelii in Ghana

Ficus vogelii is a primitive monoecious species, in which staminate and pistillate flowers are distributed throughout the syconium without localization. There is no bimodal structural distinction between seed flowers and gall flowers, and any pistillate flower is capable of seed production. Each syconium follows a development cycle lasting approximately 45 days. The chief pollen vector is the agaonid wasp Allotriozoon heterandromorphum , which is an obligate symbiont. Adult females of this species have mesothoracic "pockets" in which pollen is carried. Adult males do not display the anther-cutting activity reported in other species. The life cycle of the pollinator is described in relation to the developmental cycle of the syconium.     

天仙果与两种隐头花序小蜂的相互关系

天仙果（Ficus erecta var.beecheyana）花为单性花、雌、雄异株、分别形成雌、雄花序,雌花序着生雌花,雄花序着生雄花和瘿花。花序中生活着银纹榕小蜂（Blastophaga silverstriana）和榕长尾小蜂（Sycoscapter sp.）。前者是唯一能进入雄花序腔产卵或雌花序腔传粉的昆虫,是天仙果专一性共生的传粉者;后者不能进入花序,在花序外通过产卵器将卵产在瘿花子房中,是植食性的寄生者。自然状态下天仙果每个雄花序均被2种小蜂产卵,平均每个花序出飞银纹榕小蜂208.2只、榕长尾小蜂64.2只。人为封堵花序口,银纹榕小蜂无法进入花序产卵,平均每个花序出飞榕长尾小蜂165.6只,是自然状态下的2.5倍,显然,2种小蜂互为竞争对手,榕长尾小蜂是榕-榕小蜂共生体系的破坏者。     

On the origin of the fig: phylogenetic relationships of Moraceae from ndhF sequences

The majority of species in the mulberry family (Moraceae) are figs (Ficus), marked by a specialized inflorescence (syconium) and an obligate mutualism with pollinating fig wasps. Because of the unique morphology of the syconium, it has been difficult to investigate the evolutionary position of the fig. We sequenced the chloroplast gene ndhF to examine relationships in Moraceae and to elucidate shifts in reproductive traits. The reclassification of tribes is warranted, and the limits of Artocarpeae, Moreae, and Castilleae are revised to reflect evolutionary relationships. The results point to ancestral dioecy in Moraceae and multiple origins of monoecy, androdioecy, and gynodioecy. Ancestral wind pollination gave way to insect pollination at least twice. Strong support for the sister-group relationship of a revised Castilleae with Ficus suggests that entomophily and involucral bracts encircling the flowers preceded the evolution of the syconium. Bracts surround flowers in Castilleae only during early development, but in Ficus the involucre and the receptacle enclose the fruit as well. Molecular dating suggests that fig pollination is at least 80-90 million years old. The diversity of Ficus relative to its sister group is a likely consequence of ancient specialization and cospeciation with pollinating fig wasps.     

鸡嗉果榕榕小蜂产卵时序与种群数量分析

榕树与传粉榕小蜂的互惠共生体系被多种非传粉榕小蜂利用。在同一个榕果中,具有较高种群密度的传粉榕小蜂和多种非传粉榕小蜂生存在一起并相互作用。通过野外观察和采样分析的方法,对鸡嗉果榕内5种榕小蜂（传粉榕小蜂Ceratosolen gravelyi;非传粉榕小蜂Apocrypta sp., Philotrypesis dunia, Platyneura cunia和Sycoscaptertr ifemmensis）的产卵行为进行了研究。结果证明,鸡嗉果榕内生活的各种榕小蜂通过比较严格的产卵时序在榕果内产卵以占领不同的生态位,这反映了这些榕小蜂各自的生物学特性。自然种群数量分析表明,单个非传粉榕小蜂物种的种群数量几乎不与传粉榕小蜂种群数量呈负相关,而所有非传粉榕小蜂物种的种群个体总量与传粉榕小蜂的种群个体数呈正相关,这可能是多个物种共存于单个榕果内的进化适应。     

爱玉及其传粉昆虫的共生关系

爱玉是榕属攀援灌木,其隐头花序中生活着薜荔榕小蜂,爱玉一年两次开花,雌雄株比1：2,雌花序中平均有5503朵雌花。雄花序中平均有6308朵瘿花,自然状态上结实率和成虫瘿率分别为83.52%,51.33%。薜荔榕小蜂一年两代,1只雌蜂进入花序平均可产约600个卵或使1391朵雌花受粉结实,爱玉依赖薜荔榕小蜂传粉,否则不能结实;薜荔榕小蜂是惟一能进入花序的传粉者并依靠爱玉花序得以栖息,二者在形态结构。生理功能上高度互适,生活史上完全吻合衔接。生态策略上紧密协调,构成复杂而又精细的共生体系。     

Induction of Pectinmethylesterase in the Pericarp of Achenes of the Jelly-Fig Ficus awkeotsang Makino

Induction of pectinmethylesterase (PME) activity in the pericarpof achenes can be achieved by opening the syconium of the jelly-fig(Ficus awkeotsang Makino) and exposing the achenes to air. Amongseveral factors examined, exposure to the atmosphere is thecritical factor for the induction of the synthesis of PME inachenes obtained from green, pollinated syconia at differentdevelopmental stages. A close relationship between the rapidincrease in pectinmethylesterase activity and a rapid increasein protein content was observed in the achenes that were removedfrom the syconium and air-dried for several hours. The proteincontent and enzymatic activity reached a plateau value in onlytwenty-four hours. The dramatic increase in enzymatic activityis due to protein synthesis de novo rather than the activationof a pre-existing precursor of PME. (Received November 1, 1989; Accepted March 22, 1990)     

粗叶榕（Focis hirta）繁殖系统的特征及其共生的榕小蜂

本文对粗叶榕(Focis hirta)的外部形态、花序结构以及寄主和传粉者的繁殖特性作了比较详细的观察和研究,讨论了它们互惠共生关系的一些基本特征。它的专性传粉者是榕小蜂科(Agaonidae)榕小蜂亚科(Agaoninae)的爪哇榕小蜂(Blastophaga javana Mayr)。观察发现粗叶榕还存在两种非授粉小蜂Sycoscapter sp．和Philotrypesis sp．,它们在榕果外产卵。     

影响对叶榕及其传粉者繁殖的生态学因素

在西双版纳,分别统计了对叶榕(Ficus hispida)雌花期雌雄果的进蜂量和花后期雌雄果繁殖的多个特征值,以此来探讨自然条件下,影响对叶榕及其传粉榕小蜂(Ceratosolen solmsi marchali)繁殖的因素。结果表明:单果内有效进蜂数量是影响种子生产和传粉榕小蜂繁殖的首要因素,而雌花期进果的传粉榕小蜂并不是都能全部进入果腔传粉或产卵,大部分蜂还未进到果腔就被夹死在顶生苞片层的通道里,能进入雌果内传粉的榕小蜂为(2.72±2.04)只·果^-1,约占总进蜂量的52%;而在雄果里,能进入果腔的蜂量只有(2.08±1.65)只·果^-1,占35%左右。由于雌果内的雌花显著比雄果内的雌花多,结合单果进蜂量雌多雄少的格局,最终单果生产的种子数量 (1 891.63 ± 471.53)比传粉榕小蜂的数量 (367.20 ± 208.02) 多5倍有余。在雌果里,供给传粉的雌花数量与所生产的种子数量之间呈显著的正相关,而没有接受到花粉或不能正常受精的雌花数量与种子数量呈显著的负相关。雄果不仅生产花粉,也是传粉榕小蜂繁殖的场所,在相关于传粉榕小蜂自身繁殖力的因子中,传粉榕小蜂产卵制造的瘿花数量对其种群数量有最大的影响;影响次之的是发育过程中死亡的个体数量,它可降低30%左右的传粉榕小蜂数量;影响排在第三位的是寄主的雌花数量。此外,3类非传粉者的存在,单果内平均可减少30多只传粉小蜂。     

粗叶榕(Ficus hirta)繁殖系统的特征及其共生的榕小蜂

本文对粗叶榕(Ficus hirta Vahl)的外部形态、花序结构以及寄主和传粉者的繁殖特性作了比较详细的观察和研究, 讨论了它们互惠共生关系的一些基本特征。它的专性传粉者是榕小蜂科(Agaonidae)榕小蜂亚科(Agaoninae)的爪哇榕小蜂(Blastophaga javana Mayr)。观察发现粗叶榕还存在两种非授粉小蜂Sycoscapter sp.和Philotrypesis sp.,它们在榕果外产卵。     

Phenology of Ficus racemosa in Xishuangbanna,Southwest China1

Leaf and fig phenology (including leafing, flowering, and fruiting) and syconium growth of Ficus racemosa were studied in Xishuangbanna, China. Leaffall and flushing of F. racemosa occurred twice yearly: in mid‐dry season (December to March) and mid‐rainy season (July to September). The adult leaf stage of the first leaf production was remarkably longer than that of the second. F. racemosa bears syconia throughout the year, producing 4.76 crops annually. Asynchronous fig production was observed at a population level. Fig production was independent of leafing. Fig production peaks were not evident, but fluctuation was clear. Diameter growth rates of syconium were normally higher in early developmental stages than in later stages, and reached a peak coinciding with the female flower phase. The mean ± SD of syconium diameter of the female flower phase was 2.19 ± 0.36 cm, and reached 3.67 ± 0.73 cm of the male flower phase. Syconium diameter and receptacle cavity quickly enlarged at the female and male flower phases. Monthly diameter increment of the syconium was primarily affected by average monthly temperature, rather than rainfall or relative humidity.     

Chaos of Wolbachia Sequences Inside the Compact Fig Syconia of Ficus benjamina (Ficus: Moraceae)

Figs and fig wasps form a peculiar closed community in which the Ficus tree provides a compact syconium (inflorescence) habitat for the lives of a complex assemblage of Chalcidoid insects. These diverse fig wasp species have intimate ecological relationships within the closed world of the fig syconia. Previous surveys of Wolbachia, maternally inherited endosymbiotic bacteria that infect vast numbers of arthropod hosts, showed that fig wasps have some of the highest known incidences of Wolbachia amongst all insects. We ask whether the evolutionary patterns of Wolbachia sequences in this closed syconium community are different from those in the outside world. In the present study, we sampled all 17 fig wasp species living on Ficus benjamina, covering 4 families, 6 subfamilies, and 8 genera of wasps. We made a thorough survey of Wolbachia infection patterns and studied evolutionary patterns in wsp (Wolbachia Surface Protein) sequences. We find evidence for high infection incidences, frequent recombination between Wolbachia strains, and considerable horizontal transfer, suggesting rapid evolution of Wolbachia sequences within the syconium community. Though the fig wasps have relatively limited contact with outside world, Wolbachia may be introduced to the syconium community via horizontal transmission by fig wasps species that have winged males and visit the syconia earlier.     

Divvying up an incubator: How parasitic and mutualistic fig wasps use space within their nursery microcosm

Differential occupancy of space can lead to species coexistence. The fig–fig wasp pollination system hosts species-specific pollinating and parasitic wasps that develop within galls in a nursery comprising a closed inflorescence, the syconium. This microcosm affords excellent opportunities for investigating spatial partitioning since it harbours a closed community in which all wasp species are dependent on securing safe sites inside the syconium for their developing offspring while differing in life history, egg deposition strategies and oviposition times relative to nursery development. We determined ontogenetic changes in oviposition sites available to the seven-member fig wasp community of Ficus racemosa comprising pollinators, gallers and parasitoids. We used species distribution models (SDMs) for the first time at a microcosm scale to predict patterns of spatial occurrence of nursery occupants. SDMs gave high true-positive and low false-positive site occupancy rates for most occupants indicating species specificity in oviposition sites. The nursery microcosm itself changed with syconium development and sequential egg-laying by different wasp species. The number of sites occupied by offspring of the different wasp species was negatively related to the risk of syconium abortion by the plant host following oviposition. Since unpollinated syconia are usually aborted, parasitic wasps ovipositing into nurseries at the same time as the pollinator targeted many sites, suggesting response to lower risk of syconium abortion owing to reduced risk of pollination failure compared to those species ovipositing before pollination. Wasp life history and oviposition time relative to nursery development contributed to the co-existence of nursery occupants.     

Relationship between Ethylene and the Growth of Ficus sycomorus

The relationship between ethylene and growth was investigated in Ficus sycomorus L. A marked increase in ethylene emanation preceeded all the phases of rapid growth and ripening of the syconium.     

木瓜榕传粉生物学

 木瓜榕（Ficus auriculata Lour.）是雌雄异株植物,它只有通过大果榕小蜂（Ceratosolen emarginatus Mayr）传粉才能获得有性繁殖,大果榕小蜂也仅在木瓜榕雄果内产卵才得以繁衍后代。经两年来的实验和研究结果表明：木瓜榕繁殖能力在不同季节随进蜂量的多少而变化,雌树在4月和11月出现的两次结果高峰期与进蜂量最多的时期相遇;同时雄树与雌树在11月挂果高峰期重叠,导致该期进入雄果产卵的雌蜂量减少,进蜂量高峰推迟到部分雄果成熟、只有稀少接受果的3月下旬和4月上旬。木瓜榕在与大果榕小蜂互惠共生的进化历程中,逐渐完善了自身保证远交的繁殖机制,它们在不同程度上受到雌雄异熟、雌雄异株和短花柱雌花不亲和3种机制的共同作用。温湿度对大果榕小蜂访果行为有明显的影响,在温湿度变化缓和的早晚,有利于榕小蜂出行,雌蜂访果最为频繁。大果榕小蜂活动最佳的温湿度是：温度20～24 ℃之间、湿度85%～93%之间;温度高于29 ℃、湿度低于58% 或风雨天均不利于该蜂出行活动。榕小蜂日活动高峰的出现先后在不同季节略有差异,高温高湿的夏季榕小蜂活动出现早,7∶40达高峰;秋季榕小蜂活动推迟,高峰出现在11∶00;干凉的冬季最晚,13∶00才到达高峰。通过人工套袋、放蜂传粉试验,平均进8头的隐头果传粉效率最高,单果平均种子数量为11 247粒,结实率50.8%,未受精的败育花8 207朵;平均进蜂4头以下或10头以上的隐头果,由于花粉量不足或者雌蜂争夺资源的损伤使种子量下降,平均结实率分别达37.2% 和44.4%;放蜂试验结果与大量调查自然界中每果进蜂量和结实率的结果一致。     

Costs of inflorescence longevity for an Asian fig tree and its pollinator

In ecological situations where interactions between two species are to their mutual benefit, traits are expected to evolve to maximise the value of the timing of their encounters. Plants that depend on animals for pollination vary in the longevity of their flowers and also in how the quality of the rewards they offer varies in flowers of different ages. However, costs of floral longevity are rarely studied. Using field experiments with Ficus semicordata, a SE Asian dioecious fig tree, we examined sexual differences in syconium ageing, how the reproductive success of the plant and its pollinator change with syconium age and whether these changes are reflected in pollinator preferences. Un-pollinated syconia remained receptive to their host-specific pollinators for long periods, but eventually abort. Compared with male syconia, un-pollinated female syconia aborted more quickly and lost their ability to attract pollinators more quickly. Older pollinated female syconia were also more likely to abort. Further, declines in productivity with syconium age were also more apparent in female syconia, though older male syconia also produced fewer, smaller wasp offspring. The longevity costs are reflected in pollinator preferences. This suggests that sexual differences in duration of receptivity may be adaptive and a component of the reproductive strategies. It also indicates that placing fig wasps onto older syconia over-estimates their likelihood of being pollinated under natural conditions and prolonged receptivity increases the likelihood of pollination at the cost of reduced productivity with syconium age. This opens interesting perspectives on the co-evolution of this inter-specific interaction.     

A role for parasites in stabilising the fig-pollinator mutualism

Mutualisms are interspecific interactions in which both players benefit. Explaining their maintenance is problematic, because cheaters should outcompete cooperative conspecifics, leading to mutualism instability. Monoecious figs (Ficus) are pollinated by host-specific wasps (Agaonidae), whose larvae gall ovules in their “fruits” (syconia). Female pollinating wasps oviposit directly into Ficus ovules from inside the receptive syconium. Across Ficus species, there is a widely documented segregation of pollinator galls in inner ovules and seeds in outer ovules. This pattern suggests that wasps avoid, or are prevented from ovipositing into, outer ovules, and this results in mutualism stability. However, the mechanisms preventing wasps from exploiting outer ovules remain unknown. We report that in Ficus rubiginosa, offspring in outer ovules are vulnerable to attack by parasitic wasps that oviposit from outside the syconium. Parasitism risk decreases towards the centre of the syconium, where inner ovules provide enemy-free space for pollinator offspring. We suggest that the resulting gradient in offspring viability is likely to contribute to selection on pollinators to avoid outer ovules, and by forcing wasps to focus on a subset of ovules, reduces their galling rates. This previously unidentified mechanism may therefore contribute to mutualism persistence independent of additional factors that invoke plant defences against pollinator oviposition, or physiological constraints on pollinators that prevent oviposition in all available ovules.     

Body size in a pollinating fig wasp and implications for stability in a fig‐pollinator mutualism

The fig–fig pollinator association is a classic case of an obligate mutualism. Fig‐pollinating wasps often have to fly long distances from their natal syconia to a receptive syconium and then must enter the narrow ostiole of the syconium to reproduce. Large wasps are expected to have a greater chance of reaching a receptive syconium. In this study, we tested this hypothesis and then examined whether the ostiole selectively prevented larger pollinators from entering the syconial cavity. In Xishuangbanna, China, Ceratosolen solmsi marchali Mayr (Hymenoptera: Agaonidae) pollinates the dioecious syconia of Ficus hispida L. (Moraceae). The body size of newly emerged wasps and wasps arriving at receptive syconia were compared. Wasps arriving at receptive syconia were significantly larger than newly emerged wasps. We also compared the size of wasps trapped in the ostiole with those in the cavity. Wasps trapped in the ostiole were significantly larger than those in the syconial cavity. Thus, in the case of F. hispida, large wasps were more likely to reach receptive syconia, but the ostiole limited maximum fig wasp size. This indicates that the ostiole, as a selective filter to pollinators, stabilizes pollinator size. Hence, it helps to maintain stability in the fig–fig pollinator mutualism.