向川安瘿蜂寄生白栎虫瘿和成瘿枝的代谢组比较

虫瘿是植物受致瘿昆虫产卵和取食等刺激而异常生长形成的不正常组织。营养假说认为虫瘿组织营养物质的含量高于寄主植物的成瘿部位,而次生代谢产物的含量低于寄主植物的成瘿部位。向川安瘿蜂(Andricus mukaigawae)属膜翅目(Hymenoptera)瘿蜂科(Cynipidae),在白栎(Quercus fabri)枝条上形成虫瘿。本文基于非靶向代谢组,使用高效液相色谱-质谱检测、鉴定和比较向川安瘿蜂幼虫期虫瘿与寄主植物成瘿枝的代谢物。研究结果表明,向川安瘿蜂虫瘿和成瘿枝的代谢物组成存在差异;虫瘿的脂肪含量均高于成瘿枝,虫瘿的4种单宁和4种黄酮物质的含量均低于成瘿枝,这支持营养假说;虫瘿的氨基酸含量均低于成瘿枝,部分酚类物质的含量高于成瘿枝,这不支持营养假说。     

虫瘿与致瘿昆虫

虫瘿是由昆虫等致瘿生物诱导寄主植物而产生的一种特异组织。虫瘿对致瘿生物具有提供营养和保护等作用,虫瘿不仅有一定的经济利用和科学研究价值,而且多数致瘿昆虫是农林害虫。本文对致瘿昆虫在植物上的致瘿部位、致瘿的主要昆虫类群、虫瘿形态结构、虫瘿化学组成、虫瘿对寄主植物的影响以及虫瘿的利用等进行综述。     

虫瘿多样性及其与寄主植物和环境间关系

虫瘿是自然界极常见的生物现象,凝聚着昆虫与植物间显著、复杂而密切的协同关系。本文主要阐述了致瘿昆虫的主要类群及其在植物上的致瘿部位、虫瘿外部形态、虫瘿发育过程、虫瘿内部结构、虫瘿寄主植物多样性以及虫瘿空间分布规律等,探讨了致瘿昆虫和寄主植物间相互关系,以及影响虫瘿空间分布的环境因素等。最后对目前虫瘿生物学存在的问题及以后的研究方向进行了讨论,以期为有害虫瘿的控制和有益虫瘿的开发与利用,以及致瘿昆虫与寄主植物间协同演化关系、致瘿昆虫的致瘿机理等研究奠定一定的理论基础。     

虫瘿与其生物群落及寄主植物间的关系

虫瘿是自然界极其常见的生物现象,是植物与昆虫互作的奇特产物。本文对虫瘿生物群落多样性、虫瘿与其生物群落的关系以及虫瘿与寄主植物的关系进行概述,探讨了致瘿昆虫在虫瘿形成中的作用、植物化学对致瘿昆虫产卵交配行为的影响以及植物激素在虫瘿形成中的作用,最后对虫瘿今后的研究方向进行了讨论,为虫瘿的致瘿生物学及其瘿内生物相互关系的进一步研究奠定基础。     

植物的虫瘿与成瘿昆虫

虫瘿是植物组织遭受昆虫取食或产卵的刺激后,细胞加速分裂和异常分化而长成的畸形瘤状物或突起,它们是昆虫生活的"房子".介绍了虫瘿的形态多样性和形成过程,成瘿昆虫的多样性、生活史、寄生、食性和寄食现象,成瘿昆虫与寄主植物的关系以及人类对虫瘿的利用.     

植物虫瘿

虫瘿是造瘿昆虫诱导植物组织不正常生长产生的,它们通过释放某些酶或者植物激素刺激寄主植物细胞增大或增殖产生了特异形态的虫瘿,而这种特异形态就是造瘿昆虫遗传基因的体外表达。但虫瘿产生的分子机制不是十分清楚,文章主要对目前植物虫瘿的形态特征、形成机制等方面进行综述。     

《基于三级营养水平的进化生态学:一支黄花、作瘿昆虫及其天敌》

该书由美国普林斯顿大学出版社 1 997年出版 ,作者为ＷａｒｒｅｎＧ .Ａｂｒａｈａｍｓｏｎ和ＡｒｔｈｕｒＥ .Ｗｅｉｓ。全书通过对一支黄花、作瘿昆虫及其天敌间的相互作用的研究 ,建立了田地生态和进化生态相互作用的系统模式 ,阐明了三级营养水平相互作用的关系。主要内容包括 :( 1 )进化生态学、植物及昆虫的相互关系 ;( 2 )茎杆作瘿昆虫的天敌和一支黄花 :三级营养水平互作的模式系统 ;( 3 )硕蝽Ｅｕｒｏｓｔａ对一支黄花的影响 ;( 4)寄主植物对作瘿昆虫的抗性 ;( 5)作瘿昆虫对寄主植物的选择 ;( 6)由硕蝽Ｅｕｒｏｓｔａ产生的虫瘿 ;(…     

奇特的虫瘿

虫瘿作为自然界一种奇特的生物现象 ,主要是由致瘿昆虫通过产卵、取食或分泌化学物质刺激植物体而形成的。该文对虫瘿的致瘿原因和成瘿过程进行了详细描述 ,讨论了它与人类和植物的关系 ,并就其中富含脂肪、蛋白质等化学物质展望了未来人类在医疗、工业、园林等行业对虫瘿的开发和利用。     

蓟马诱导的鹅掌柴叶片虫瘿组织的生理生化响应

以蓟马诱导的鹅掌柴叶片管状虫瘿为材料,分析了虫瘿和非虫瘿组织的抗氧化活性及其它生理响应以及营养物质的含量、分配等。结果发现虫瘿组织中许多生理指标如过氧化氢浓度、过氧化物酶和苯丙氨酸解氨酶活性以及丙二醛含量都比非虫瘿组织低。虫瘿组织比非虫瘿组织光合速率下降而呼吸速率增强,虫瘿组织转变为一个营养库能够富集较多的营养物质。仅仅使用植物激素和蓟马萃取物不能诱导虫瘿的形成,但是,细胞分裂素类植物生长调节物可以引起类似蓟马诱导虫瘿的早期反应。     

中华蚊母树虫瘿类型及其致瘿昆虫生活史初探

初步观察了中华蚊母树(Distylium chinense(Fr.)Diels)不同类型虫瘿的发生过程及致瘿昆虫生活史。结果表明,中华蚊母树的虫瘿有3种类型,分别为叶/枝上大型虫瘿、叶上泡状虫瘿和叶柄/果上球型虫瘿。三者均为单室封闭型,次生开口。经鉴定致瘿昆虫均为半翅目蚜科昆虫,其中叶上泡状虫瘿致瘿昆虫为蚊母新胸蚜Neothoracaphis yanonis Matsumura。该虫3月初在虫瘿内营孤雌生殖,繁殖2代,5月底前飞离出瘿。     

Non-native plants rarely provide suitable habitat for native gall-inducing species

For insect herbivores, a critical niche requirement—possibly the critical niche requirement—is the presence of suitable host plants. Current research suggests that non-native plants are not as suitable as native plants for native herbivores, resulting in decreases in insect abundance and richness on non-native plants. Like herbivores, gall-forming insects engage in complex, species-specific interactions with host plants. Galls are plant tissue tumors (including bulbous or spindle-shaped protrusions on leaves, stems and other plant organs) that are induced by insects through physical or chemical damage (prompting plants to grow a protective tissue shell around the insect eggs and larvae). As such, we hypothesized that gall-inducing insect species richness would be higher on native than non-native plants. We also predicted higher gall-inducing insect species richness on woody than herbaceous plants. We used an extensive literature review in which we compiled gall host plant species by genus, and we assigned native or non-native (or mixed) status to each genus. We found that native plants host far more gall-inducing insect species than non-native plants; woody plants host more gall-inducing species than herbaceous plants; and native woody plants host the most gall-inducing species of all. Gall-inducing species generally are a very cryptic group, even for experts, and hence do not elicit the conservation efforts of more charismatic insects such as plant pollinators. Our results suggest that non-native plants, particularly non-native woody species, diminish suitable habitat for gall-inducing species in parallel with similar results found for other herbivores, such as Lepidopterans. Hence, the landscape-level replacement of native with non-native species, particularly woody ones, degrades taxonomically diverse gall-inducing species (and their inquilines and parasitoids), removing multiple layers of diversity from forest ecosystems.

     

Manipulation of host plant cells and tissues by gall-inducing insects and adaptive strategies used by different feeding guilds

Biologists who study insect-induced plant galls are faced with the overwhelming diversity of plant forms and insect species. A challenge is to find common themes amidst this diversity. We discuss common themes that have emerged from our cytological and histochemical studies of diverse neotropical insect-induced galls. Gall initiation begins with recognition of reactive plant tissues by gall inducers, with subsequent feeding and/or oviposition triggering a cascade of events. Besides, to induce the gall structure insects have to synchronize their life cycle with plant host phenology. We predict that reactive oxygen species (ROS) play a role in gall induction, development and histochemical gradient formation. Controlled levels of ROS mediate the accumulation of (poly)phenols, and phytohormones (such as auxin) at gall sites, which contributes to the new cell developmental pathways and biochemical alterations that lead to gall formation. The classical idea of an insect-induced gall is a chamber lined with a nutritive tissue that is occupied by an insect that directly harvests nutrients from nutritive cells via its mouthparts, which function mechanically and/or as a delivery system for salivary secretions. By studying diverse gall-inducing insects we have discovered that insects with needle-like sucking mouthparts may also induce a nutritive tissue, whose nutrients are indirectly harvested as the gall-inducing insects feeds on adjacent vascular tissues. Activity of carbohydrate-related enzymes across diverse galls corroborates this hypothesis. Our research points to the importance of cytological and histochemical studies for elucidating mechanisms of induced susceptibility and induced resistance.     

Insect-induced effects on plants and possible effectors used by galling and leaf-mining insects to manipulate their host-plant

Gall-inducing insects are iconic examples in the manipulation and reprogramming of plant development, inducing spectacular morphological and physiological changes of host-plant tissues within which the insect feeds and grows. Despite decades of research, effectors involved in gall induction and basic mechanisms of gall formation remain unknown. Recent research suggests that some aspects of the plant manipulation shown by gall-inducers may be shared with other insect herbivorous life histories. Here, we illustrate similarities and contrasts by reviewing current knowledge of metabolic and morphological effects induced on plants by gall-inducing and leaf-mining insects, and ask whether leaf-miners can also be considered to be plant reprogrammers. We review key plant functions targeted by various plant reprogrammers, including plant-manipulating insects and nematodes, and functionally characterize insect herbivore-derived effectors to provide a broader understanding of possible mechanisms used in host-plant manipulation. Consequences of plant reprogramming in terms of ecology, coevolution and diversification of plant-manipulating insects are also discussed.     

Adaptive significance of gall formation for a gall-inducing aphids on Japanese elm trees

Insect galls are abnormal plant tissues induced by external stimuli from parasitizing insects. It has been suggested that the stimuli include phytohormones such as auxin and cytokinins produced by the insects. In our study on the role of hormones in gall induction by the aphid Tetraneura nigriabdominalis, it was found that feedback regulation related to auxin and cytokinin activity is absent in gall tissues, even though the aphids contain higher concentrations of those phytohormones than do plant tissues. Moreover, jasmonic acid signaling appears to be compromised in gall tissue, and consequently, the production of volatile organic compounds, which are a typical defense response of host plants to herbivory, is diminished. These findings suggest that these traits of the gall tissue benefit aphids, because the gall tissue is highly sensitive to auxin and cytokinin, which induce and maintain it. The induced defenses against aphid feeding are also compromised. The abnormal responsiveness to phytohormones is regarded as a new type of extended phenotype of gall-inducing insects.     

Changes in Clonal Poplar Leaf Chemistry Caused by Stem Galls Alter Herbivory and Leaf Litter Decomposition

Gall-inducing insects are highly specialized herbivores that modify the phenotype of their host plants. Beyond the direct manipulation of plant morphology and physiology in the immediate environment of the gall, there is also evidence of plant-mediated effects of gall-inducing insects on other species of the assemblages and ecosystem processes associated with the host plant. We analysed the impact of gall infestation by the aphid Pemphigus spirothecae on chemical leaf traits of clonal Lombardy poplars (Populus nigra var. italica) and the subsequent effects on intensity of herbivory and decomposition of leaves across five sites. We measured the herbivory of two feeding guilds: leaf-chewing insects that feed on the blade (e.g. caterpillars and sawfly larvae) and skeletonising insects that feed on the mesophyll of the leaves (e.g. larvae of beetles). Galled leaves had higher phenol (35%) and lower nitrogen and cholorophyll contents (35% respectively 37%) than non-galled leaves, and these differences were stronger in August than in June. Total herbivory intensity was 27% higher on galled than on non-galled leaves; damage by leaf chewers was on average 61% higher on gall infested leaves, whereas damage by skeletonising insects was on average 39% higher on non-galled leaves. After nine months the decomposition rate of galled leaf litter was 15% lower than that of non-galled leaf litter presumably because of the lower nitrogen content of the galled leaf litter. This indicated after-life effects of gall infestation on the decomposers. We found no evidence for galling x environment interactions.     

Anti-insect effects of the gall wall of Baizongia pistaciae [L.], a gall-inducing aphid on Pistacia palaestina Boiss

The Enemy hypothesis is a theoretical framework for understanding the adaptive nature of galls induced in host plants by insects. Contrary to other gall inducing insects, like Cynipids or sawflies, this hypothesis has not been studied for the gall aphids on pistachio trees in the Middle East. Galls on plants are supposed to protect their inducers from other organisms, including herbivores feeding on the host plant and possibly feeding on the gall tissue. Assuming that among aphid enemies there are numerous insects which have to perforate the gall wall to access the aphids inside, determining whether the gall wall has anti-insect properties should be one of the first steps in dealing with this hypothesis. In the present research using Baizongia pistaciae [L.], an aphid that creates perfectly closed galls in Pistacia palaestina Boiss, laboratory experiments were first conducted on a herbivore, the stored grain pest, Tribolium castaneum Herbst, to assess chemical anti-insect activities of the gall tissue, and an effort was made to understand why these properties do not harm the aphids inside the gall. Addition of fresh gall tissue to food reduced the population growth of flour beetles. Non-polar organic extracts had contact toxicity for larvae of these insects, and an impact on the feeding preferences of the adults. These results indicate chemical anti-insect activities of the gall tissue. The research also reveals that the permeability of the gall wall to non-polar volatile compounds is important to the survival of the aphids inside the gall cavity. These findings do not allow us to reject the Enemy hypothesis in the gall-inducing aphids/Pistacia trees interactions.     

Feeding by Hessian Fly (Mayetiola destructor [Say]) Larvae on Wheat Increases Levels of Fatty Acids and Indole-3-Acetic Acid but not Hormones Involved in Plant-Defense Signaling

Gall-inducing insects exert a unique level of control over the physiology of their host plants. This control can extend to host–plant defenses so that some, if not most, gall-inducing species appear to avoid or modify host plant defenses to effect production of their gall. Included among gall insects is Hessian fly (Mayetiola destructor [Say], Diptera: Cecidomyiidae), a damaging pest of wheat (Triticum aestivum L.) and an emerging model system for studying plant–insect interactions. We studied the dynamics of some defense-related phytohormones and associated fatty acids during feeding of first instar Hessian fly larvae on a susceptible variety of wheat. We found that Hessian fly larvae significantly elevated in their host plants’ levels of linolenic and linoleic acids, fatty acids that may be nutritionally beneficial. Hessian fly larvae also elevated levels of indole-3-acetic acid (IAA), a phytohormone hypothesized to be involved in gall formation, but not the defense-related hormones jasmonic (JA) and salicylic acids. Moreover, we detected in Hessian fly-infested plants a significant negative relationship between IAA and JA that was not present in control plants. Our results suggest that Hessian fly larvae may induce nutritionally beneficial changes while concomitantly altering phytohormone levels, possibly to facilitate plant-defense avoidance.     

Gall insects can avoid and alter indirect plant defenses

Parasitic species can dramatically alter host traits. Some of these parasite-induced changes can be considered adaptive manipulations that benefit the parasites. Gall-inducing insects are parasites well known for their ability to alter host-plant morphology and physiology, including the distribution of plant defensive compounds. Here it was investigated whether gall-inducing species alter indirect plant defenses, involving the release of volatile compounds that are attractive to foraging natural enemies. Using field and factorial laboratory experiments, volatile production by goldenrod (Solidago altissima) plants was examined in response to attack by two gall-inducing species, the tephritid fly Eurosta solidaginis and the gelechiid moth Gnorimoschema gallaesolidaginis, as well as the meadow spittlebug, Philaenus spumarius, and the generalist caterpillar Heliothis virescens. Heliothis virescens elicited strong indirect defensive responses from S. altissima, but the gall-inducing species and spittlebugs did not. More significantly, infestation by E. solidaginis appeared to suppress volatile responses to subsequent attack by the generalist caterpillar. The extensive control that E. solidaginis apparently exerts over host-plant defense responses may reduce the predation risk for the gall inducer and the subsequent herbivore, and could influence community-level dynamics, including the distribution of herbivorous insect species associated with S. altissima parasitized by E. solidaginis.     

The impact of kleptoparasitic invasions on the evolution of gall-size in social and solitary Australian Acacia thrips

Many species of gall-inducing Acacia thrips are attacked by kleptoparasitic thrips who enter the gall, destroy the occupants, and then use the gall for producing their own offspring. The hypothesis tested here is that pressure exerted by ldeptoparasites （genus Koptothrips） not only provoked the evolution of soldiers in the gall-inducing clade, but have also influenced the evolution of gall size and morphology. Various size dimensions of invaded galls were compared to those of uninvaded galls using data from six gall-inducing species and their kleptoparasites. For the non-social gall-inducing species （K. ellobus and K. nicholsoni） invaded galls showed no significant size differences from galls that had not been invaded. For the four social gall-inducingspecies （K. habrus, K. intermedius, K. waterhousei and K. morrisi） invaded galls were significantly narrower and/or shorter than uninvaded galls. Galls of social species that had not been invaded and contained adult soldiers were significantly larger than galls where soldiers were still at a larval stage, suggesting that gall size is related to gall age in these species. An hypothesis is proposed that links the timing of invasion by kleptoparasites to size of the host gall： induction of a smaller gall by host founders will reduce the period of vulnerability to invasion （before soldiers become adults） for social thrips by allowing foundresses in these smaller galls to begin laying soldierdestined eggs relatively sooner.