粘虫蛾复眼背、腹区视杆结构的差异

根据光学和电子显微镜的观察,粘虫蛾复眼背、腹区域的视杆结构具有以下主要差异:1)背方小眼视杆的长度短于腹方小眼视杆的长度。2)在横切面上,背方小眼视杆的中段近似方形。该段间细胞的视小杆为三角形,每个具有平行排列的微绒毛。整个视杆包含两个互相垂直的微绒毛轴。腹方小眼视杆的中段为风扇形。间细胞的视小杆为“V”字形,微绒毛排列不平行。3)背方小眼基细胞的视小杆几乎位于气管反光层远侧,而腹方小眼甚至延伸到气管反光层内。 在背方和腹方小眼视杆的内段,每个间细胞的微绒毛均平行,且排列在基细胞的大形视小杆周围。更深层,在其它细胞的轴突均已相继出现的水平上,基细胞的大形视小杆仍然可见。 最后,对形态上的特点,在功能上可能具有的一些意义也进行了初步讨论。     

栖境不同的两种跳甲复眼结构比较

栖息于荫暗隐蔽处的蛇莓跳甲(Altica fragariae)和向阳开阔地的萎陵跳甲(A.Ampelophaga)的复眼外部形态及小眼微细结构有如下相同特征：两复眼均比较小,呈“八”字型排列在头部近背方的两侧;每个小眼含有一个双凸面的角膜锥体、4个森氏细胞和7个小网膜细胞;2个主色素细胞及11-12个附色素细胞围绕在小眼的外缘;小网膜细胞和色素细胞内均有丰富色素颗粒,当光照强度发生变化时,小网膜细胞内的色素颗粒发生位移;在视杆中段横切面上,视杆由7个微绒毛呈平行排列的矩形视小杆组成,其中的6个视小杆互相连成一个近似六边形的框架,将另一个视小杆围在中央。两种跳甲复眼结构的主要差异有：蛇莓跳甲每个复眼大约仅有150个小眼,而萎陵跳甲约有2印个;复眼曲率半径前者只有后者的一半;视杆中段横切面上,视杆占整个小网膜面积的比率两虫分别为37%和25%,蛇莓跳甲高于萎陵跳甲。对以上形态结构特征可能具有的功能意义进行了初步讨论。     

棉铃虫蛾复眼的形态及显微结构

棉铃虫[Heliothis armigera(Hubner)]蛾复眼的外形约为椭球体绕长轴等切的2/5。最前和最后小眼之间的夹角约为150°,而最上和最下小眼之间的夹角约为180°,一个复眼大约包括8,900个小眼。每个小眼有一套由角膜、晶锥细胞及晶锥所组成的屈光器和分布在不同水平面上的7-9个小网膜细胞。其周围被6个次虹膜细胞所包围。两个明显可见的区域性差异为:1)复眼不同区域内小眼长度不等,背部区域最短,侧、后、腹和前各区域相继增加。2)背部区域视杆中段的横切面为矩形,其它区域的视杆为放射形。本文将小眼及其周围,从远端到基部分13个层次进行了结构上的描述。     

异色瓢虫显现变种复眼的形态、显微结构及其光暗条件下的适应性变化

复眼是昆虫的主要视觉器官,对于其寻找食物、配偶、栖息场所以及学习记忆等活动具有重要作用。本研究采用扫描电镜和石蜡切片技术对异色瓢虫显现变种Harmonia axyridis ab. conspicua复眼的外部形态和内部显微结构进行了观察。结果发现：(1)复眼近椭圆形,位于头部两侧,触角窝处有缺刻,小眼表面光滑平坦,无角膜乳突结构。其雌、雄成虫复眼的小眼数分别约为705和691;(2)复眼中心区域小眼呈六边形,排列紧密,边缘区域的小眼为不规则的四边形或五边形; (3)每个小眼由角膜、晶锥、8个小网膜细胞、视杆、基膜以及色素细胞组成。晶锥由4个晶锥细胞构成,8个小网膜细胞中6个位于边缘、2个位于中央;(4)暗条件下复眼显微结构存在明显差异：光适应条件下,色素颗粒主要分布在晶锥和视杆交界处的周围,周围视杆呈环形,内、外两侧均被色素颗粒包围;暗适应条件下,色素颗粒发生纵向移动,均匀地分布在晶锥和视杆的周围,周围视杆发生扭曲呈不规则的多角形,仅外侧有色素颗粒分布。结果表明,异色瓢虫显现变种的复眼属于并列复眼,可通过色素颗粒的纵向移动以及周围视杆扭曲变形等机制来适应外界明暗环境的变化。     

龟纹瓢虫成虫的复眼形态及其显微结构

利用光镜、组织切片法观察了龟纹瓢虫Propylaea japonica(Thunberg)成虫的复眼形态及其显微结构。结果如下:(1)头正前方观,复眼外形似半球,且后方稍向内合拢。每个复眼约包括630个小眼。(2)每个小眼是由1套屈光器(1个角膜和1个晶锥)、6至8个小网膜细胞及其特化产生的视杆和基细胞等几部分组成。晶体周围及小网膜色素细胞内均含有丰富的色素颗粒。(3)小眼整体纵切显示,其上、下段色素颗粒分布相对较多,中段分布较少。(4)明、暗适应状态对小眼的色素颗粒分布有影响,性别对其分布无明显影响。明适应状态下,其色素颗粒较均匀地分布于视杆两侧上下,暗适应状态时色素颗粒则主要分布在视杆部位的上侧,显示其具有一定的重叠眼性质;而在相同的明、暗适应状态下其雌、雄成虫复眼的色素颗粒分布间无明显差异。     

双斑蟋复眼和视叶的显微结构

【目的】为探索昆虫视觉信号处理的重要神经结构,详细观察和描述了直翅目(Orthoptera)蟋蟀科(Gryllidae)代表性昆虫双斑蟋Gryllus bimaculatus De Geer复眼和视叶的组织学结构特征。【方法】利用扫描电镜技术和组织学切片技术,观察分析了30只双斑蟋的复眼和视叶组织学结构。【结果】双斑蟋复眼约有3400个小眼,均为六边形结构,小眼间隙内分布有机械感受器——感觉毛和钟形感受器。每个小眼均由角膜、晶锥、感杆束、6个网膜细胞及基膜等构成。视叶呈两个扇形结构,由三大神经纤维网构成,分别为神经节层、外髓、内髓。【结论】双斑蟋复眼表面具有少量感觉毛和钟形感受器,每个小眼均由角膜、晶锥、感杆束、6个网膜细胞及基膜等构成,属并列像眼,视叶由三大神经纤维网构成。     

飞蝗复眼生理和结构上的节律变化

采用细胞内记录和光镜方法研究了飞蝗(Locusta migratoria)夜间和日间在暗适应和明适应状态下小网膜细胞角敏感度以及晶锥和小网膜细胞之间区域结构上的变化.结果表明小网膜细胞角敏感度的变化不仅仅由于晶锥周围主色素细胞色素颗粒的移动,而且也由于小眼感杆束结构上的节律变化.     

螺旋粉虱成虫的复眼形态及其内部结构

采用扫描电镜和组织切片法,观察了螺旋粉虱Aleurodicus dispersus Russell成虫复眼的形态及其显微结构。结果表明,螺旋粉虱复眼半球状,呈“∞”形分布于头部两侧,单个复眼约由253个小眼组成;各小眼面微凸,复眼中心区域小眼多为规则的六边形,密集排列似蜂窝状;近背区边缘小眼多为五边形或近圆形,小眼排列疏松,且少量相邻小眼的间距较大。雌、雄复眼小眼面积约为85μm2。单个小眼由角膜、晶体、网膜细胞及其特化产生的视杆和基细胞等几部分组成。晶体有四个晶锥细胞构成,晶体、视杆周围和色素细胞内均含有大量的色素颗粒。螺旋粉虱的复眼属于并置复眼。光、暗条件下,小眼的色素颗粒分布有所不同。光适应条件下,色素颗粒较均匀地分布于视杆上下两侧;暗适应状态下,色素颗粒则主要分布在视杆上侧和晶体下侧。而在相同的明、暗适应条件下,性别对色素颗粒的分布无显著影响。     

黑翅土白蚁有翅成虫复眼的形态结构

采用组织切片法光镜下观察黑翅土白蚁Odontotermes formosanus(Shiraki)有翅成虫的复眼形态结构及光、暗适应条件下色素颗粒移动的规律。结果如下:(1)头正前方观,复眼外部形态略呈圆形。(2)有翅成虫复眼类型属于并列像眼,每只复眼约由360个小眼组成。(3)每个小眼是由1套屈光器(1个角膜和1个晶锥)、小网膜色素细胞、视杆和基细胞等几部分组成。小网膜色素细胞内均含有丰富的色素颗粒。(4)在光适应条件状态下,屈光器及视杆周围的色素颗粒主要分布在视杆部位的上侧,暗度适应条件状态时则较均匀地分布于视杆两侧上下;性别对色素颗粒分布无明显影响。     

亲土苔蛾成虫复眼超微结构

【目的】重叠型眼在昆虫复眼演化中起着重要作用。本研究旨在阐明夜出型亲土苔蛾Manulea affineola复眼类型及结构特征,以期填补灯蛾亚科昆虫复眼研究的空白,扩充夜出型昆虫复眼的特征数据,为探讨重叠型眼的变异趋势及复眼演化提供依据。【方法】运用光学和透射电子显微技术观察亲土苔蛾成虫复眼的超微结构。【结果】亲土苔蛾成虫复眼具有一个透明区,由6个次级色素细胞的透明胞质构成。小眼具8个视网膜细胞,其中1个视网膜细胞较短,仅位于小眼基部。在透明区内,7个视网膜细胞聚集成一束,其远端与晶体束末端相接,但并不形成视杆。在透明区下方,这7个视网膜细胞形成一个中心融合的视杆。在复眼背缘区的小眼的视杆具有近似矩形的横截面,而其余小眼的视杆具多分支状截面。【结论】亲土苔蛾成虫复眼属于重叠型眼;复眼背缘区的矩形视杆很可能与昆虫的偏振敏感性有关。     

The compound eye of Parnara guttata (Insecta,Lepidoptera, Hesperiidae): Fine structure of the ommatidium

Summary The fine structure of an ommatidium of a skipper butterfly, Parnara guttata, has been studied using the electron microscope. Each ommatidium has nine retinula cells, which were classified into three groups: two distal, six medial and one basal retinula cells. The rhabdomeres of the distal retinula cells are localized in the distal part of the rhabdom, while those of the six medial retinula cells appear throughout most of the rhabdom. The rhabdomere of the basal retinula cell occupies only the basal part of the rhabdom. The rhabdomeres of four medial cells are constructed of parallel microvilli, while fan-like microvilli form the rhabdomeres of other two medial retinula cells. The distal and basal retinula cells have rhabdomeres consisting of both parallel and fan-like microvilli. This is the first time the construction of the rhabdomeres of the distal and basal retinula cells has been described in such fine detail for a skipper butterfly. Nine retinula cell axons of each ommatidium extend to the first neuropile of the optic lobe, the lamina ganglionaris. No difference was found in the number of retinula cells of an ommatidium or the shape of the rhabdom between the dorsal and ventral regions of the compound eye.     

Ultrastructure of the eye of a euphausiid crustacean

The compound eye of the Antarctic euphausiid Euphausia superba is a spherical clear zone eye. The dioptric system consists of a hexagonally-faceted cornea, two corneagenous cells, two crystalline cone cells which form the bipartite crystalline cone, and two accessory cone cells. The dioptric system of each ommatidium is separated from that of adjacent ommatidia by six distal pigment cells and a basement membrane. The proximal tip of the crystalline cone is cupped by the distal ends of the seven retinula cells whose nuclei are arranged in a staggered array slightly distal to the middle of the clear zone. In the distal half of the clear zone, each narrow retinula cell column is surrounded by large proximal extensions of the six distal pigment cells. The pigment cells narrow more proximally and terminate at the proximal basement membrane. A specialized axial channel complex extends from the crystalline cone through the clear zone, and is continuous with a conical refractive element which caps the distal end of the rhabdom. The rhabdom is fused, and made up of alternating highly birefringent layers of orthogonally-oriented microvilli. It is surrounded by a narrow extra-cellular space which is continuous with the distal refractive element and a second conical refractive element at the proximal end of the rhabdom.     

Larval and adult eye of the Western Rock Lobster (Panulirus longipes)

A number of differences exists between the compound eyes of larval and adult rock lobsters, Panulirus longipes. The larval eye more closely resembles the apposition type of compound eye, in which retinula cells and rhabdom lie immediately below the cone cells. The adult eye, on the other hand, is a typical clear-zone photoreceptor in which cones and retinula cell layers are separated by a wide transparent region. The rhabdom of the larval eye, if cut longitudinally, exhibits a "banded" structure over its entire length; in the adult the banded part is confined to the distal end, and the rhabdom is tiered. Both eyes have in common an eighth, distally-located retinula cell, which possesses orthogonally-oriented microvilli, and a peculiar lens-shaped "crystal", which appears to focus light onto the narrow column of the distal rhabdom. Migration of screening pigment on dark-light adaptation is accompanied by changes in sensitivity and resolution of the eye. Retinula cells belonging to one ommatidium do not arrange into one single bundle of axons, but interweave with axons of four neighbouring facets in an extraordinarily regular fashion.     

灰茶尺蠖成虫复眼的超微结构及其明暗适应中的变化

【目的】明确灰茶尺蠖Ectropis grisescens成虫复眼的超微结构及其明暗适应中的变化,探究其调光机制。【方法】采用超景深显微镜测定了灰茶尺蠖成虫复眼的小眼数量、间角、直径和曲率半径等外部参数,并通过组织切片、光学显微镜和透射电子显微镜等技术观察了复眼的内部超微结构;通过光学显微镜观察了灰茶尺蠖成虫复眼在明暗环境中分别适应2 h后晶锥结构及色素颗粒的位置变化。【结果】灰茶尺蠖成虫复眼呈半球形,雌、雄虫单个复眼分别有2 502±105和3 123±78个小眼。小眼自远端至近端由角膜、晶锥、透明区构成的屈光层和由15个视网膜细胞构成的感光层组成。2个初级色素细胞包裹着晶锥,自角膜近端延伸至视网膜细胞核区的远端;每个小眼外围由6个次级色素细胞围绕,自角膜近端延伸至基膜;在透明区内14个视网膜细胞聚集成束(非感杆束),远端与晶锥束末端连接,在感光层内形成闭合型感杆束,延伸至第15个视网膜细胞(基部视网膜细胞)。在明暗适应时,灰茶尺蠖复眼的晶锥细胞间出现开闭,色素颗粒进行纵向位移,以适应外界的光强度的变化。【结论】灰茶尺蠖成虫复眼属于重叠像眼,感杆束为“14+1”模式;屏蔽色素颗粒的移动是其复眼适应外界光强度变化的重要机制。     

Regional distribution of three ultrastructural retinula types in the retina of Cataglyphis bicolor Fabr. (Formicidae,Hymenoptera)

Summary The retina of Cataglyphis bicolor was investigated by electron microscopy. Three types of structurally distinct retinulae were found and mapped throughout the compound eye: Type I is composed of four unpigmented thin cells, four larger pigmented cells as well as a basal ninth cell. Its rhabdom possesses a round cross section and four microvilli directions. This type occupies most of the dorsal two-thirds of the retina. Type II consists of two thin cells, two intermediate cells and four large cells. A basal ninth cell is also present; the rhabdom is as in type I. Type II retinulae are located in the ventral third of the retina. Type III ommatidia are unique within the Hymenoptera: there are four large pigmented cells, four thinner unpigmented cells and a basal ninth cell. The rhabdom, however, has a dumb-bell shaped cross section; two small cells lie at its opposed extremities and the remaining six cells have mutually perpendicular microvilli orientations. This type of retinula is found at the dorso-medial eye margin. Serial sectioning in this region revealed a conical shaped rhabdom without any torsion along the longitudinal axis. The rhabdomere cross section was calculated from distal and proximal thin sections. Angular statistics were applied to the microvilli directions of all three ommatidial types to determine the degree of order. A possible functional significance of the structural specializations of the different eye regions is discussed.Supported by Swiss National Science Foundation, Grant No. 3.814.72 awarded to Prof. Dr. R. Wehner. This work is part of a Ph. D. thesis. I wish to thank Prof. Dr. R. Wehner for continuous support and my colleagues Dr. P. Duelli and Dr. E. Meyer for a fruitful collaboration     

双翅目昆虫复眼性特化光感受器的比较研究

雄性双翅目昆虫,包括家蝇Musca domestica、丽蝇Calliphora erythrocephala、华虻Tabanus mandarinus和憎黄虻Atylotus miser Szilady,其复眼性特化光感受器中央小网膜细胞R₇的分布从背区扩展到腹区。在雄性家蝇、华虻和憎黄虻复眼中,性特化光感受器中央小网膜细胞R₇的感杆延伸到基底膜,并同中央小网膜细胞R₈的感杆并列排列。但在雄性丽蝇复眼中,性特化光感受器中央小网膜细胞R₇的感杆不延伸到基底膜。在雌性双翅目昆虫复眼中,性特化光感受器中央小网膜细胞R₇仅仅分布在复眼的腹区,其数量比中央小网膜细胞R₈少得多。     

Fine structural description of the lateral ocellus of Craterostigmus tasmanianus Pocock, 1902 (Chilopoda: Craterostigmomorpha) and phylogenetic considerations

The lateral lens eye of adult Craterostigmus tasmanianus Pocock, 1902 (a centipede from Australia and New Zealand) was examined by light and electron microscopy. An elliptical, bipartite eye is located frontolaterally on either side of the head. The nearly circular posterior part of the eye is characterized by a plano-convex cornea, whereas no corneal elevation is visible in the crescentic anterior part. The so-called lateral ocellus appears cup-shaped in longitudinal section and includes a flattened corneal lens comprising a homogeneous and pigmentless epithelium of cornea-secreting cells. The retinula consists of two kinds of photoreceptive cells. The distribution of the distal retinula cells is highly irregular. Variable numbers of cells are grouped together in multilayered, thread-like unions extending from the ventral and dorsal margins into the center of the eye. Around their knob-like or bilobed apices the distal retinula cells give rise to fused polymorphic rhabdomeres. Both everse and inverse cells occur in the distal retinula. Smaller, club-shaped proximal retinula cells are present in the second (limited to the peripheral region) and proximal third of the eye, where they are arranged in dual cell units. In its apical region each unit produces a small, unidirectional rhabdom of interdigitating microvilli. All retinula cells are surrounded by numerous sheath cells. A thin basal lamina covers the whole eye cup, which, together with the distal part of the optic nerve, is wrapped by external pigment cells filled with granules of varying osmiophily. The eye of C. tasmanianus seemingly displays very high complexity compared to many other hitherto studied euarthropod eyes. Besides the complex arrangement of the entire retinula, the presence of a bipartite eye cup, intraocellar exocrine glands, inverse retinula cells, distal retinula cells with bilobed apices, separated pairs of proximal retinula cells, medio-retinal axon bundles, and the formation of a vertically partitioned, antler-like distal rhabdom represent apomorphies of the craterostigmomorph eye. These characters therefore collectively underline the separate position of the Craterostigmomorpha among pleurostigmophoran centipedes. The remaining retinal features of C. tasmanianus agree with those known from other chilopod eyes and, thus, may be considered plesiomorphies. Characters like the unicorneal eye cup, sheath cells, and proximal rhabdomeres with interdigitating microvilli were already present in the ground pattern of the Pleurostigmophora. Other retinal features were developed in the ancestral lineage of the Phylactometria (e.g., large elliptical eyes, external pigment cells, polygonal sculpturations on the corneal surface). The homology of all chilopod eyes (including Notostigmophora) is based principally on the possession of a dual type retinula.     

The Fine Structure of the Compound Eye of Tanais cavolinii Milne-Edwards (Crustacea: Tanaidacea)

Abstract The compound (apposition) eyes of Tanais cavolinii are not well developed: the number of ommatidia is small and there are certain irregularities in structure. The refractive components are formed by the cornea and the cone. The latter is built up by two cone cells. In addition, there are two accessory cone cells confined to the distal part of the cone. The eight pigmented retinular cells extend from the cornea to the basement membrane. Proximal to the cone, they form a fused continuous rhabdom, which in cross section has a rectangular outline. In the middle part of the rhabdom, the microvilli are arranged perpendicular to the long axis of the rhabdom when seen in cross section. The microvilli outside of this area can be arranged either parallel or perpendicular to the microvilli of the middle part. Other irregularities occur in the ommatidium, e.g. the position of the retinular cell nuclei, which are found at different levels. Extensions from the cone cells fuse and form a mesh proximal to the rhabdom. Between the mesh and basal lamina is a basal cell type enveloping the proximal parts of the retinular cells and their axons. These cells also form the basal lamina, which delimits the compound eye from the haemocoel. No special pigment cells are present in the compound eye of Tanais cavolinii.     

The Anostracan Rhabdom and the Basement Membrane. An Ultrastructural Study of the Artemia Compound Eye (Crustacea)

Abstract The ommatidia of the compound eyes of Artemia salina L. are normally composed of four crystalline cone cells containing glycogen. The cells are enveloped by two so-called “cellules épidermiques juxta-cristallines”. There are also six pigmented retinula cells, all contributing to the rhabdom. A peculiar feature of the Artemia crystalline cone cells is that their elongated parts, the so-called cone cell roots, widen and flatten proximally, forming interdigitating “endfeet”. The basement membrane thus consists of a cellular portion combined with the basal lamina. The main mass of the rhabdom of the Artemia eye is built up by five retinula cells, two contributing a smaller part. The microvilli are oriented in four directions, two being orthogonal. The sixth cell contributes on two small portions to the rhabdom in the distalmost and a more proximal position. The rest of it runs axon-like outside the omnatidium. Where the sixth cell wedges in, the direction of the microvilli is changed and has no orthogonal pattern. Two rhabdom types of compound eyes are distinguished: the decapod or banded or layered rhabdom: and the anostracan rhabdom with continuous rhabdomeres.