Spectral sensitivity of photoreceptors in insect compound eyes: Comparison of species and methods

Summary Three different methods were used to determine the spectral sensitivity of retinula cells in the compound eyes of three species of hymenopteran insects (Apis mellifera, Melipona quadrifasciata, Osmia rufa). The conventional flash method gives the least reliable results. Sensitivity is extremely sensitive to small fluctuations of the resting potential and long lasting changes induced by preceding test flashes. The ramp method, which speeds up a spectral scan to about 1 min and keeps effective illumination constant at every flash, determines S() much more reliably. The best results are obtained with the spectral scan method, which provides the experimenter with aS() function of high spectral resolution within 20 s. Using this method we demonstrate that the high observed variability inS() of individual receptors is the result of the inadequacy of the flash method, which was the only method used in earlier studies.Double microelectrode experiments and variations of the stimulus conditions reveal that field potentials and return flow of electric current produced by activated neighboring cells have no effect in the bee eye. We conclude that the model of Shaw (1975, 1981) of current flow in the locust and fly eye does not apply to the bee eye. Very rare recordings (about 1%) of UV receptors with hyperpolarizing responses to long wavelength light are interpreted as having a synaptic inhibitory connection to green receptors.The improvement of spectral measurements of single receptors allows us for the first time to model the spectral input to a color-coding network with great precision.     

草地贪夜蛾和其它五种重要鳞翅目害虫蛹的形态特征比较

【目的】田间草地贪夜蛾Spodopterafrugiperda(J.E.Smith)蛹与斜纹夜蛾Spodopteralitura Fabricius、甜菜夜蛾Spodoptera exigua(Hübner)、粘虫Mythimna separata(Walker)、棉铃虫Helicoverpa armigera(Hübner)和亚洲玉米螟Ostrinia furnacalis 5种重要鳞翅目害虫蛹容易混淆。明确草地贪夜蛾与其它5种重要的鳞翅目害虫蛹的形态差异,为田间鳞翅目害虫蛹的准确鉴别和田间调查提供依据。【方法】采用体式显微镜拍照观察并分析草地贪夜蛾蛹、斜纹夜蛾蛹、甜菜夜蛾蛹、粘虫蛹、棉铃虫蛹和亚洲玉米螟蛹的外部形态特征,根据相关特征差异编制了区分草地贪夜蛾与此5种鳞翅目害虫的检索表和快速区分表。【结果】草地贪夜蛾蛹主要特征为中足末端到达下颚末端之前,触角末端到达中足末端之前;中胸背板前缘略直;第4-7腹节背面前缘着生多行粗点刻;腹部末端臀棘上着生1对基部分开呈八字形的刺。草地贪夜蛾蛹腹部末端臀棘部位与其它5种害虫均不相同,辅以附肢位置、中胸背板前缘线和腹部点刻等特征可以准确将其与斜纹夜蛾、甜菜夜蛾、粘虫、棉铃虫和亚洲玉米螟的蛹区分。斜纹夜蛾中胸背板前缘线和臀棘上的刺与草地贪夜蛾有异;甜菜夜蛾下颚与中足位置及臀棘上的刺与草地贪夜蛾有异;粘虫腹部点刻和臀棘上的刺与草地贪夜蛾有异;棉铃虫触角末端位置和腹部末端的刺与草地贪夜蛾有异;亚洲玉米螟腹足遗迹和臀棘上的刺与草地贪夜蛾有异。【结论】根据蛹的结构特征,可以区分草地贪夜蛾与斜纹夜蛾、甜菜夜蛾、粘虫、棉铃虫和亚洲玉米螟等害虫的蛹。     

Development of the compound eyes of dragonflies (Odonata). III. Adult compound eyes

The distribution of ommatidial diameters and interommatidial angles, as determined by measuring the angles between the optic axes of adjacent ommatidia, are mapped across the surface of the compound eyes of a variety of species selected for different adult behaviors, developmental histories, and taxonomic positions. The size of the visual fields, prey capture foveas, foveas composed of large dorsal ommatidia, and other specializations in the numbers of ommatidia that view various directions in the visual field are discussed in relation to adult behavior. Advanced species have less resemblance between their larval and adult eyes than primitive species. In contrast to their larvae, adults increase the monocular resolution of each eye at the expense of binocular vision. Most species have foveas which view in approximately the anterior direction, instead of in a region of binocular overlap, and many species have foveal bands which view along the horizon. Some advanced perching species, which approach their prey and other odonates from below, have an additional vertical foveal band that views along a vertical plane from the anterior direction to a more dorsal direction. The most unusual foveal band is seen in active flying species. The large dorsal ommatidia of the migratory Anax junius, which cover approximately one third of the eye surface, view a narrow region of the visual field that extends along a plane from the most lateral direction of one eye to a dorsal direction, and continues without interruption to the most lateral direction of the other eye.     

Larval polytene chromosomes of black flies (Simulium) from Thailand. I. Comparison among five species in the subgenus Gomphostilbia enderlein

Larval polytene chromosome maps of Simulium (G.) asakoae and S. (G.) sp. g in the ceylonicum-group and S. (G.) angulistylum, S. (G.) decuplum and S. (G.) siamense in the batoense-group of the subgenus Gomphostilbia from Thailand are presented. These species have three pairs of chromosomes (2n = 6). Light stained centromeric bands were observed in the chromosomes of S. (G.) asakoae, S. (G.) sp. g, S. (G.) decuplum and S. (G.) siamense, whereas heavy dark centromeric bands were present in S. (G.) angulistylum. The best distinguishing character of Simulium species in the subgenus Gomphostilbia is the position of the nucleolar organizer in the short arm of chromosome I. The Ring of Balbiani and the double bubble are located in chromosome arm IIS in all species except for S. (G.) angulistylum, which showed these cytological markers in chromosome arm IIIS. A low chromosomal polymorphism was recorded in all species except for S. (G.) sp. g, which exhibited a standard polytene chromosome. Inversion polymorphisms found in this study conformed to Hardy–Weinberg equilibrium and were not associated with sex. These species have different specific markers and banding patterns although homologous banding sequences were found in chromosome arm IIS in S. (G.) asakoae, S. (G.) sp. g, S. (G.) decuplum and S. (G.) siamense and chromosome arm IIIS in S. (G.) angulistylum. Our results showed no evidence of a sibling species complex within any taxon.     

Relationships between five species ofLolium (Poaceae)

Morphological analysis and electrophoresis of seed proteins of fiveLolium species disclosed that they form two distinct groups corresponding to those recognized from compatibility data.Lolium temulentum andL. remotum of the self-pollinated group were shown to be distinct but closely related species. Morphological intergradation and high similarities between protein profiles ofL. perenne, L. multiflorum andL. rigidum (cross-pollinated species) suggest little genetic differentiation between these taxa. This implies that treatment at the infraspecific level might better accomodate the data.     

The characterization of microsporidian isolates (Nosematidae: Nosema) from five important lepidopteran pests in Taiwan

Microsporidian isolates from five lepidopteran pests-Spodoptera litura, Spodoptera exigua, Helicoverpa armigera, Plutella xylostella, and Pieris spp.-were compared by spore morphology, infectivity to S. litura, Western-blot banding patterns, the sequences of small subunit rRNA gene (SSUrRNA sequence), and random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR). All the isolates could infect experimentally and multiply in the larvae of S. litura. The S. exigua isolate showed the highest virulence to the larvae of S. litura while the P. xylostella isolate showed the lowest. No significant differences either in spore morphology or in SSUrRNA sequences of these isolates were found. The SSUrRNA sequences of these isolates confirmed they are members of the genus Nosema. Based on the result of Western-blot hybridization with the rabbit anti-Nosema spodopterae spore antiserum, three serotypes could be distinguished: N. spodopterae (S. litura isolate) and Pi. spp. isolate; S. exigua and H. armigera isolates; and P. xylostella isolate. The amplicons of RAPD-PCR with 60 primers yielded clear patterns that were selected and used for identification and also for phylogenic analysis of these five isolates. Based on analysis by the computer, isolates could be clearly divided into three groups that were coincident with the serotypes; therefore we suggest that N. spodopterae and isolates of Pi. spp., S. exigua, and H. armigera are more closely related in phylogenesis. In addition, in the amplification with the Nosema bombycis specific primer set, only DNAs from P. xylostella isolate and N. bombycis yielded amplicons. Therefore, we suggest that four isolates, excluding the P. xylostella isolate, are N. spodopterae, and the taxonomic position of P. xylostella isolate needs to be elucidated.     

Comparison of five strains of a parthenogenetic species,Macrotrachela quadricornifera (Rotifera,Bdelloidea)

Five clonal populations belonging to the parthenogenetic species Macrotrachela quadricornifera were analyzed electrophoretically. The populations stemmed from samples collected from different environments paired geographically: water bodies (C, P, F) and terrestrial mosses (Ml, M2). The six enzymes considered were: leucine amino peptidase (LAP), arginine phosphokinase (APK), glucose phosphate isomerase (PGI), and esterases (EST) and malic enzyme (ME). The results are interpreted under the assumption that bdelloid rotifers have a diploid chromosome set. A genetic interpretation of the banding patterns was attempted. A relatively high degree of enzymatic polymorphism among the strains was found. Only 27% of alleles are shared by all strains. The relationship among the strains was examined by single-link cluster analysis: we can distinguish moss and water populations, regardless of their geographic origins, and in accord with the results of a life-history traits study on the same strains. The differences in life-history parameters among the five strains may be due not only to phenotypic plasticity induced by the environment, but to real genetic divergence.     

Development of the compound eyes of dragonflies (Odonata). II. Development of the larval compound eyes

The development of the compound eye was analyzed by marking individual ommatidia and by studying naturally occurring pigment band patterns. New ommatidia are added to the eye along its anterior margin. This changes the directions of view of the older ommatidia with the greatest change occurring in the fovea. New ommatidia are added to the fovea medially, and old ones are removed laterally as their interommatidial angles and directions of view in the visual field change. Over one-third of the aeshnid ommatidia are foveal during at least one of the early larval instars, and are then used for peripheral vision later in development. The design of each ommatidium is a compromise so that it is adapted for all stages of development, but sometimes better adapted for one instar than for others. Factors which are balanced for best vision are lens diameter, facet admission function, interommatidial angle, and inclination of the optic axis to the eye surface. Ommatidia are described in terms of these factors throughout their life history, from initial differentiation anteriorly, through passage through the fovea, to their final relatively posterior location.     

Chromosomal characterisation of five lepidopteran cell lines of Malacosoma disstria (Lasiocampidae) and Christoneura fumiferana (Tortricidae).

Chromosome number and morphology have been examined in four established cell lines (Md63, Md66, Md108, and Md109) of the forest tent caterpillar, Malacosoma disstria Hübner, and one (Cf124) of the spruce budworm, Choristoneura fumiferana (Clemens). Chromosome number distributions of Md63 (mode = 112) Md108 (mode = 103), Md109 (mode= 103), and Cf124 (mode = 110) overlap sufficiently to prevent identification of individual lines by number alone. However, Md66 is exceptional in possessing a modal number of 157. One large chromosome occurs in cells of all lines. The presence of this chromosome, the lack of any distinct polyploid series among chromosome numbers encountered, and the general inverse relationship between number and size of chromosomes, suggest that the high level of heteroploidy characteristic of these and other lepidopteran cell lines reflects not only a possible polyploid origin but also extensive chromosomal rearrangement and fragmentation. Tolerance for such change is attributed to the holokinetic organisation of lepidopteran chromosomes. A distinct heteropycnotic body is present in about 10% of Cf124 cell nuclei, and can be used as a marker for this line. This body may represent the sex chromatin normally encountered in somatic cells of female C. fumiferana.     

五种啮齿类动物mtDNA蛋白编码基因序列变化的比较

目的利用本实验室测定的中国地鼠、金黄地鼠和GenBank中田鼠、小鼠、大鼠的线粒体全基因组序列,比较分析五种啮齿类动物的mtDNA蛋白编码基因序列的变异,探讨其分子进化关系。方法将五种动物各自的13个蛋白编码基因分别连接成一个序列,用DNAstar-EditSeq分析软件计算每个序列的碱基长度和组成,计算蛋白编码基因的碱基和氨基酸的差异。以人为外群,基于连接在一起的13个蛋白编码基因的氨基酸序列,用MEGA4.0软件通过最大简约性法(MP)和非加权成对平均数法(UPGMA)构建进化树。结果在五种啮齿动物的13个蛋白基因序列中,A、T、C、G碱基的平均含量为32.4%、29.6%、26.2%和11.9%,中国地鼠mtDNA各蛋白编码序列以及其编码的氨基酸序列与其他物种相比,与金黄地鼠的相应序列差异最小,与大鼠mtDNA各蛋白编码序列以及其编码的氨基酸序列差异较大。分子进化树也显示中国地鼠和金黄地鼠的亲缘关系最近,与小鼠、大鼠存在的差异相对大。结论五种动物的碱基组成的百分比中显示G的相对缺乏,相互之间的进化关系与传统的分类地位基本吻合。     

Phenolics of five yam (dioscorea) species

Cyanidin-3-glucoside, (+)-catechin and the procyanidin dimers ‘B-1’ and ‘B-3’ were identified as phenolic constituents of Dioscorea alata tubers, and strong evidence for the presence of a procyanidin trimer and a tetramer was found. The quantity of (+)-catechin and relative proportions of the procyanidin dimers were determined in 10 cultivars of five of the main edible yam species.     

Serological studies on five species of Pseudococcidae (Homoptera)

Abstract. Populations of Planococcus cini, Planococcus ficus, Pseudococcus obscurus, Pseudococcus calceolanae and Pseudococcus longispinus were selected for immunoelectrophoretic tests from which correlation and distance coefficients were calculated. Cluster analysis of serological data allowed construction of a dendrogram in which the phylogenetic relationships among the five species are presented. The conclusions were found to be in agreement with modern views on taxonomic interrelations among the five species based on female and male morphology. The recent separation of Planococcus citn' and Planococcus ficus as independent species is emphasized.     

Application of high-resolution DNA melting for genotyping in lepidopteran non-model species: Ostrinia furnacalis (Crambidae)

Development of an ideal marker system facilitates a better understanding of the genetic diversity in lepidopteran non-model organisms, which have abundant species, but relatively limited genomic resources. Single nucleotide polymorphisms (SNPs) discovered within single-copy genes have proved to be desired markers, but SNP genotyping by current techniques remain laborious and expensive. High resolution melting (HRM) curve analysis represents a simple, rapid and inexpensive genotyping method that is primarily confined to clinical and diagnostic studies. In this study, we evaluated the potential of HRM analysis for SNP genotyping in the lepidopteran non-model species Ostrinia furnacalis (Crambidae). Small amplicon and unlabeled probe assays were developed for the SNPs, which were identified in 30 females of O. furnacalis from 3 different populations by our direct sequencing. Both assays were then applied to genotype 90 unknown female DNA by prior mixing with known wild-type DNA. The genotyping results were compared with those that were obtained using bi-directional sequencing analysis. Our results demonstrated the efficiency and reliability of the HRM assays. HRM has the potential to provide simple, cost-effective genotyping assays and facilitates genotyping studies in any non-model lepidopteran species of interest.     

Supernumerary segments in five species of grasshoppers (Orthoptera: Acridoidea)

Supernumerary segments have been observed in five species of grasshoppers: Calliptamus barbarus, Oedipoda fuscocincta, Acrotylus insubricus, Omocestus raymondi and Chorthippus ariasi. In four cases they are located in the S-chromosomes, but in A. insubricus they are carried by the megameric pair (M₉). In C. barbarus and O. fuscocincta we have observed non-homologous association during diplotene between the extra segments and the X-chromosome. The supernumerary segments of these two species are distally located. However, in anaphase-I the unequal bivalents divide reductionally in 30% and 20% of the cells, respectively. Finally, the supernumerary segments of C. barbarus do not produce any effect on mean chiasma frequency, but they decrease significantly the between-cell variance of chiasmata in males carrying them.     

5种松属树种光合功能及叶绿素快相荧光动力学特征比较

以松属5种代表树种日本五针松、华山松、白皮松、油松和赤松为研究对象,比较了它们针叶的形态特征、光合速率和叶绿素快相荧光动力学方面的异同.结果表明:5种松树的针叶形态特征存在显著差异,油松的针叶长度和密度最大;白皮松的叶绿素含量最高;但赤松的光合速率最大,日本五针松的光合速率最小.5种松树针叶的光合速率与气孔导度呈正相关.5种松树的叶绿素快速荧光诱导动力学曲线的差异主要表现在J相和I相.尽管5种松树光系统Ⅱ(PSⅡ)最大光化学效率(Fv/Fm)、潜在光化学活性(Fv/Fo)以及到达最大荧光所需的时间(Tfm)差异不显著,但日本五针松的反应中心关闭净速率dV/dto和dVG/dto以及J相和I相的相对可变荧光强度(Vj和Vi)显著大于其他4种松树,能量分配比率Ψo、φEo、φRo显著低于其他4种松树.这可能与日本五针松的质体醌库大小(Sm)、质体醌库还原速率(Sm/Tfm)和质体醌A(QA)的周转次数(N)最小有关.日本五针松的性能指数PI(ABS/CSo/CSm)和光合驱动力(DF)均显著低于其他4种松树,而赤松PI和DF最高.其中PI(Cso)和PI(CSm)与5种松树的净光合速率呈显著正相关,可以作为评价松树光合能力的荧光指标.     

Comparison of five cladoceran species in short- and long-term copper exposure

The study was carried out to assess the effect of both short-and long-term copper exposure on five cladoceran species differing in body size and habitat, i.e. Daphnia magna, D. pulex, D. galeata, Bosmina longirostris, and Chydorus sphaericus. The species-specific 48 h EC₅₀ values for fed neonates were used to determine the chronic exposure levels (52% and 65% of the EC₅₀ values). The experiment was run at two food levels. Long-term copper exposure retarded growth in each of the species studied. However, the copper treatments did not affect the clutch sizes of the experimental animals. At a low food level, copper exposure increased mortality in every species studied. The intrinsic rate of increase, r, was reduced in the copper-exposed populations. The sensitivity to copper was higher in the small lake species, compared to D. magna and D. pulex that are commonly used in standard toxicity tests. Of the species studied, B. longirostris had the highest sensitivity to both acute and chronic copper stress. The different sensitivities of the species studied are discussed in an ecological context.     

Cytogenetic analysis of five Hypostomus species (Siluriformes, Loricariidae)

In this work, we analyzed the karyotypes of five Hypostomus species. Hypostomus cf. heraldoi, from the Mogi-Gua?u River, had 2n = 72 chromosomes, with a nucleolar organizer region (NOR) in one chromosomal pair. Hypostomus regani, from the Mogi-Gua?u River had 2n = 72 chromosomes with NORs in two chromosomal pairs. Hypostomus sp., from the Mogi-Gua?u River basin, had 2n = 68 chromosomes, with NORs in two chromosomal pairs. Hypostomus aff. agna, from Cavalo Stream, had 2n = 74 chromosomes with NORs in two chromosomal pairs. Hypostomus cf. topavae, from Carrapato Stream, had 2n = 80 chromosomes, with NORs in two chromosomal pairs. Hypostomus species showed marked diversity in the karyotypic formula, which suggested the occurrence of several Robertsonian rearrangements and pericentric inversions during the evolutionary history of this genus. This hypothesis was supported by the occurrence of a large number of uniarmed chromosomes and multiple NORs in a terminal position in most species and may be a derived condition in the Loricariidae.