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。     

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。     

蚜虫对杨属植物不同寄生部位的形态适应(英文)

为了明确取食相同植物不同部位和营不同虫瘿的蚜虫是否存在形态适应,论文以取食杨属Populus植物的10种蚜虫为研究对象,基于蚜虫喙末端、各足跗节和爪的形态测量数据,对122个克隆的形态变异通过一般的统计描述、典型变量分析(canonical variates analysis,CVA)以及聚类分析等方法进行了研究。结果显示,不同的蚜虫克隆间形态特征存在分异,与不同的虫瘿类型和取食部位相关。3个典型变量分析明显地区分了形成虫瘿和不形成虫瘿的蚜虫克隆,在叶片上形成真虫瘿和伪虫瘿的克隆以及不产生虫瘿的克隆,并形成明显的克隆簇。而用于分析的形态学特征,如喙末端、跗节和爪的测量值,其一般统计描述的差异也支持这些区分。蚜虫自然种群不同克隆簇的区分很好地对应了不同的取食部位和不同的虫瘿类型,且各簇的形态特征体现了各自的特点,表明了蚜虫对杨属植物已经形成了良好的形态适应。同时,也初步讨论了不同蚜虫克隆簇形态适应产生的原因。并建议在基于形态特征探讨昆虫的系统发育关系和进行传统分类时,必须考虑昆虫形态特征的适应性;在深入研究昆虫与寄主植物相互之间关系时,需要将各种形态特征综合考虑并关注其它的影响因素。     

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。     

没食子蜂与没食子

没食子为没食子蜂幼虫寄生在没食子树幼枝所产生的虫瘿(Gall),它是植物体受到昆虫的刺激而生成的不正常构造。此类昆虫在昆虫学上统称为“产瘿昆虫”或“虫瘿制造者”。没食子蜂是植食性昆虫(Phytophagous insect)中的一种产瘿昆虫。虫瘿的形状、位置常因造瘿昆虫的不同而各有特征。昆虫产卵于植物内,就在产卵的部位开始长出不寻常的生长组织来。昆虫卵在这异常的组织内孵化、成长。虫瘿随着幼虫的发育而膨大,幼虫以虫瘿所生出来的某些特别物质为食(通常昆虫很少吃虫瘿本身的组织),至羽化时,成虫始脱瘿而出。     

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.     

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。     

一种花瘿蚊(双翅目:瘿蚊科)与其寄主植物对萼猕猴桃Actinidia valvata的相互关系(英文)

猕猴桃属植物Actinidia spp,自然分布于中国的亚热带地区。对萼猕猴桃A.valvata的花芽受Pseudasphond ylia 瘿蚊属一未知种的寄生而形成花芽虫瘿,这种花芽瘿由于近年来在制药工业上的应用而受到重视。在中国中南地区研究对萼猕猴桃—瘿蚊的相互关系过程中,我们的记载表明该造瘿昆虫在一定情形下可能改变其寄主植物的雌雄异株之生殖模式。野外调查与实验证明寄主植物受寄生而形成虫瘿的比例很高。但虫瘿密度却于不同沟谷间,或同一沟谷内不同植株间有异。在二条沟谷内,92％和75％植株分别被寄生,而在第3条沟谷内没有植株受寄生。受寄生的雄性植株只产生虫瘿,而受寄生的雌性植株则产生正常果与虫瘿。有迹象显示当寄主植株有虫瘿形成时其正常果数量也更多。作者认为这可能是昆虫诱导功能上雌雄异株植物形成雄性异株雌雄同株之生殖模式的少数例子     

致瘿昆虫对寄主植物生理和代谢的影响

虫瘿是致瘿昆虫刺激植物后诱导形成的畸形结构,是研究植物与昆虫协同进化的理想材料,同时致瘿昆虫通常还是重要的农林害虫。因此,研究致瘿昆虫对寄主植物的影响,一方面可进一步揭示致瘿昆虫与植物的关系,有助于揭示成瘿植物生长的一般过程;另一方面,了解成瘿植物对致瘿昆虫的响应有助于筛选植物抗性指标、抗性基因、敏感基因等,为抗性育种提供理论基础。本文主要围绕致瘿昆虫对寄主植物光合作用、生理和代谢活动的影响等进行了综述。致瘿昆虫普遍引起寄主植物光合色素减少、光合速率降低,虫瘿内部组织中糖类、氨基酸类等初生代谢物质含量增加,虫瘿外部组织中酚类、黄酮类等非挥发性和萜类为主的挥发性次生代谢物质含量增加,寄主植物POD和SOD等保护酶活性增强,以及IAA, SA和JA等植物激素含量提高。现有研究资料显示,致瘿昆虫对寄主植物生理和代谢影响的研究仍处于初级阶段,其影响机制还需要进一步研究。     

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。     

A look into the invisible: ultraviolet-B sensitivity in an insect (Caliothrips phaseoli) revealed through a behavioural action spectrum

Caliothrips phaseoli, a phytophagous insect, detects and responds to solar ultraviolet-B radiation (UV-B; λ ≤ 315 nm) under field conditions. A highly specific mechanism must be present in the thrips visual system in order to detect this narrow band of solar radiation, which is at least 30 times less abundant than the UV-A (315–400 nm), to which many insects are sensitive. We constructed an action spectrum of thrips responses to light by studying their behavioural reactions to monochromatic irradiation under confinement conditions. Thrips were maximally sensitive to wavelengths between 290 and 330 nm; human-visible wavelengths (λ ≥ 400 nm) failed to elicit any response. All but six ommatidia of the thrips compound eye were highly fluorescent when exposed to UV-A of wavelengths longer than 330 nm. We hypothesized that the fluorescent compound acts as an internal filter, preventing radiation with λ > 330 nm from reaching the photoreceptor cells. Calculations based on the putative filter transmittance and a visual pigment template of λ_max = 360 nm produced a sensitivity spectrum that was strikingly similar to the action spectrum of UV-induced behavioural response. These results suggest that specific UV-B vision in thrips is achieved by a standard UV-A photoreceptor and a sharp cut-off internal filter that blocks longer UV wavelengths in the majority of the ommatidia.     

Insect cells as hosts for the expression of recombinant glycoproteins

Baculovirus-mediated expression in insect cells has become well-established for the production of recombinant glycoproteins. Its frequent use arises from the relative ease and speed with which a heterologous protein can be expressed on the laboratory scale and the high chance of obtaining a biologically active protein. In addition to Spodoptera frugiperda Sf9 cells, which are probably the most widely used insect cell line, other mainly lepidopteran cell lines are exploited for protein expression. Recombinant baculovirus is the usual vector for the expression of foreign genes but stable transfection of - especially dipteran - insect cells presents an interesting alternative. Insect cells can be grown on serum free media which is an advantage in terms of costs as well as of biosafety. For large scale culture, conditions have been developed which meet the special requirements of insect cells.With regard to protein folding and post-translational processing, insect cells are second only to mammalian cell lines. Evidence is presented that many processing events known in mammalian systems do also occur in insects. In this review, emphasis is laid, however, on protein glycosylation, particularly N-glycosylation, which in insects differs in many respects from that in mammals. For instance, truncated oligosaccharides containing just three or even only two mannose residues and sometimes fucose have been found on expressed proteins.These small structures can be explained by post-synthetic trimming reactions. Indeed, cell lines having a low level of N-acetyl--glucosaminidase, e.g. Estigmene acrea cells, produce N-glycans with non-reducing terminal N-acetylglucosamine residues. The Trichoplusia ni cell line TN-5B1-4 was even found to produce small amounts of galactose terminated N-glycans. However, there appears to be no significant sialylation of N-glycans in insect cells. Insect cells expressed glycoproteins may, though, be 1,3-fucosylated on the reducing-terminal GlcNAc residue. This type of fucosylation renders the N-glycans on one hand resistant to hydrolysis with PNGase F and on the other immunogenic. Even in the absence of 1,3-fucosylation, the truncated N-glycans of glycoproteins produced in insect cells constitute a barrier to their use as therapeutics. Attempts and strategies to mammalianise the N-glycosylation capacity of insect cells are discussed.     

Impact of urbanization on a gall-inhabiting Lepidoptera assemblage: the importance of reserves in urban areas

This paper examines the structure of a Lepidoptera assemblage in an urban environment in South Africa. The Lepidoptera inhabit fungus-induced galls on Acacia karroo. Habitat patches supporting the moth assemblage were sampled from rural, urban-reserve, suburban and city sites and the habitat quality at each of these sites was quantified. Gall occupancy, larval density and species richness were lowest at the most disturbed, city sites. Non-parametric multivariate techniques showed that the moth-assemblage structure did not differ significantly at rural and urban-reserve sites. Assemblage structure at the suburban sites was variable and appeared to be transitional in structure between the city assemblage and the rural and urban-reserve assemblages. Habitat quality variables however were weakly correlated with moth-assemblage structure. The contribution of urban reserves to the local sustainability of this Lepidoptera assemblage emphasizes the importance of maintaining green areas in and around cities.     

Insect diversity over 36 years at a protected Sierra Nevada (California) site: towards an evaluation of the insect apocalypse hypothesis

1. Recent authors have suggested that declines of insect abundance or diversity, documented first for particular insect taxa of high interest (e.g., butterflies, bees), may apply to insect diversity more generally. This has led to an urgent call for analysis of additional longitudinal datasets to examine trends in general insect diversity.
2. Here we present a dataset gathered from 1982 to 2018 by advanced undergraduate students and graduate students enrolled in a taxonomy course that involved collecting as many insect families as possible over a 5-week period at a high-elevation protected forested site in the Sierra Nevada, California, USA.
3. The data do not support any consistent gain or loss of family-level richness between 1982 and 2018 (no linear trend); a non-linear model suggested a possible small decrease in family-level richness collected between 1986 and 1990, followed by a gradual increase from 1990 to 2018. Neither weather variables nor collector experience or skill appeared to explain among-year variation in collected insect diversity.
4. We urge caution in attempting to draw conclusions from single-site, longitudinal datasets like this one; a definitive answer to the hypothesis of a broad, global decline of insect diversity will require the joint analysis of many datasets like the one we share here.

     

Plant characteristics determine insect borer assemblages on Protea species in the Cape Fynbos, and importance for conservation management

The influence of regional climate, biotope and host-plant variables on the frequency of occurrence of insect borers associated with infructescences of Protea species in the species-rich flora of the Cape Fynbos was investigated. Large samples of infructescences (n=1000) were collected on a seasonal basis and borers identified and quantified. Data were analysed using DECORANA and CANOCO so as to correlate environmental variables with borer occurrence. Distinct differences in frequency of occurrence of the various insect taxa were recorded on the various plant species studied. These differences were primarily accounted for by physical host-plant characteristics (infructescence and seed set variables), and secondarily, by biotope variables and climatic factors. Fynbos plant characteristics therefore play a major role in determining insect abundance. Plant diversity in the Fynbos is maintained by burning. These management burns, however, should not be applied too frequently or over areas large enough to extirpate any borer species. As these borers are excellent umbrellas for many other insects, their conservation covers Fynbos insect diversity in general.     

Effects of elevated temperature and carbon dioxide on the nutritional quality of leaves of oak (Quercus robur L.) as food for the Winter Moth (Operophtera brumata L.)

1. Pedunculate Oak trees were grown in ambient and elevated temperatures and CO₂. Leaves were fed to Winter Moth caterpillars reared either in constant conditions or with the trees (caged or on-tree).
2. Caterpillars in constant conditions ate the same mass and produced the same mass of faeces whether fed elevated or ambient temperature leaves. However, less was assimilated from elevated leaves, resulting in lighter pupae and fewer, lighter eggs.
3. Caterpillars in constant conditions ate more and produced more faeces when fed elevated CO₂ leaves than when fed ambient CO₂ leaves, but the mass assimilated and pupal mass were unchanged.
4. Caged caterpillars reared with the trees from which they were fed had constant pupal mass in all treatments, but pupated earlier at elevated temperature. Pupal mass was also unaffected when caterpillars fed on the trees.
5. Nitrogen was reduced in both elevated temperature and elevated CO₂ leaves. Increased fibre in the former prevented increased consumption and resulted in reduced pupal mass and fecundity. Reduced fibre in the latter allowed increased consumption, resulting in pupae of normal mass.
6. Despite the clear effect of nutrient quality, experiments rearing caterpillars and trees together suggest that anticipated climatic change will have no nutritional effect on Winter Moth development.     

Establishment and characterization of a cell line from embryos of the Indianmeal moth,Plodia interpunctella

A cell line, UMN-PIE-1181, initiated in November, 1981, from embryos of a malathion-resistant strain of Indianmeal moth, Plodia interpunctella, was in the 83rd passage on January 28, 1985. The line consists of single, small, fibroblastlike cells that are polyploid with chromosome numbers ranging from 56 to 180. Growth rate is dependent on seeding density, there being no growth at or below seeding densities of $\text{2 ×}\text{10}{}^5\text{5}\text{,}\text{ml}$; optimum growth requires a fetal bovine serum concentration of at least 5%. Twenty-nine isozymes were examined. Five enzymes from the cell lines resolved well and subsequently were compared to enzymes extracted from 4-day-old embryos and other life stages of the insects. Phosphomannose isomerase, malic enzyme, malate dehydrogenase, phosphoglucose isomerase, and glucose-6-phosphate dehydrogenase in extracts from the cultured cells and from the insects had identical patterns. Two bands for glutamate-oxalacetate transaminase, present in the cell line, were not observed in the tissue extracts. Furthermore, lactate dehydrogenase from the cultured cells appeared as four bands but was not detectable in any of the samples run from the various life stages of the insects.     

Some effects of CGA 72662 on larval development in the housefly,Musca domestica (L.)

Summary

Houseflies reared on artificial diet supplemented with a range of concentrations of CGA 72662 suffered severe developmental disruption at the larval stage. Death was preceded by the appearance of a range of cuticular lesions and abnormalities. These cuticular abnormalities have been observed under the light and electron microscopes.     

Locomotor control by the central complex in Drosophila-An analysis of the tay bridge mutant

Several aspects of locomotor control have been ascribed to the central complex of the insect brain; however, the role of distinct substructures of this complex is not well known. The tay bridge1 (tay1) mutant of Drosophila melanogaster was originally isolated on the basis of reduced walking speed and activity. In addition, tay1 is defective in the compensation of rotatory stimuli during walking and histologically, tay1 causes a mid-sagittal constriction of the protocerebral bridge, a constituent of the central complex. Cloning of the tay gene revealed that it encodes a novel protein with no significant homology to any known protein. To associate the behavioral phenotypes with the anatomical defect in the protocerebral bridge, we used different driver lines to express the tay cDNA in various neuronal subpopulations of the central brain in tay1-mutant flies. These experiments showed an association of the aberrant walking speed and activity with the structural defect in the protocerebral bridge. In contrast, the compensation of rotatory stimuli during walking was rescued without a restoration of the protocerebral bridge. The results of our differential rescue approach are supported by neuronal silencing experiments using conditional tetanus toxin expression in the same subset of neurons. These findings show for the first time that the walking speed and activity is controlled by different substructures of the central brain than the compensatory locomotion for rotatory stimuli.     

Insecticidal activity of Bacillus laterosporus

Strains of Bacillus laterosporus demonstrated pathogenic activity for second-instar larvae of the mosquito, Culex quinquefasciatus, but failed to demonstrate detectable pathogenicity against larvae of the cabbage looper, Trichoplusia ni. Of 29 strains of the bacterium screened, 16 displayed pathogenicity for mosquito larvae. One of the most pathogenic strains, NRS 590, also demonstrated pathogenic activity for larvae of the mosquito, Aedes aegypti, and for larvae of the black fly, Simulium vittatum. The pathogenicity for Culex larvae was associated with the cell mass rather than with the culture supernatant. A suspension of ultraviolet irradiation-killed cells demonstrated no loss in pathogenic activity, an indication that the pathogenicity is toxin mediated. The toxic substance produced by NRS 590 was found to be resistant to heating at 96°C for 10 min. The toxin was not associated with the heat-resistant, bacterial endospore or with the associated paraspore since a suspension consisting primarily of spores was not toxic to mosquito larvae. Toxic activity in stationary phase cells of NRS 590 was associated with the cell's particulate fraction rather than with the soluble fraction.