Spectral transmission through the cuticle of the American cockroach,Periplaneta americana

Small pieces of cuticle were removed from the following areas of the cockroach, P. americana, to determine the relative transmittance qualities across the visible and infrared regions of the spectrum: wing tip; abdominal tergite and sternite; light and dark pigmented areas of the pronotum; vertex; two pairs of wing tips plus underlying tergite. The transmittance across the spectral areas investigated showed significant differences in μW/cm² between the cuticular areas assayed. A single wing tip possessed high transmittance qualities whereas the vertex and lesser pigmented cuticle showed considerably lower per cent transmission.     

Phenotypic variation in adult morphology and pupal colour within and among families of the speckled wood butterfly Pararge aegeria

Abstract .1. Larvae from eggs of fifteen wild-caught speckled wood females were reared individually under common conditions (LD 18:6 h and 17 °C) in the laboratory.
2. Pupal colour (green or brown) and the following adult morphological variables that are known or assumed to be related to behavioural variation (thermoregulation, flight, crypsis) were studied: size, relative thorax mass, area of yellow patches on the dorsal forewing, size of submarginal eyespots on the dorsal hindwing, colour of the dorsal thorax, dorsal basal wing, and dorsal distal wing.
3. The results of the breeding experiment indicate significant differences in adult morphological traits among families, sexes, and pupal colour types.
4. All adult morphological variables (except spot size and thorax colouration) differed significantly among families, suggesting genetic variation underlying the phenotypic variation. Heritabilities for these features were intermediate (0.38) to high (> 1).
5. Apart from known aspects (e.g. size), novel aspects of the sexual dimorphism were found: females had paler thoraxes than males, which relates to higher abundance of fur on the thorax and hence to thermoregulatory differences.
6. Green pupae produced larger individuals with a larger relative thorax mass than brown pupae. Green pupae produced adults with a paler basal wing colour in females, but not in males. These relationships are novel and suggest a trade-off between juvenile and adult investment.     

长尾管蚜蝇Eristalis tenax体色变异的研究

通过对长尾管蚜蝇体色变异的研究,发现该种蚜蝇在体色变异方面有如下特点：（1）腹部色斑的变异形式多样,种群中以浅色者为主,深色的个体比例较少;腹部色斑变异表现出明显的性别差异,雄性变异形式比雌性丰富;（2）后足腿节颜色变异呈现出一定的连续性,从主要呈黑色（肉眼观察）到黄褐色;且这种变化与性别无关;（3）翅上暗色云斑的变化仅有2种形式,种群中具暗色云斑者占大多数;云斑的有无与性别无关;（4）体色变异与发生季节、海拔无关.     

夏块菌与青刚栎形成外生菌根形态变化的研究

夏块菌（Tuber aestivum）是一种具有较高经济价值的菌根食用菌。对夏块菌与青刚栎（Cycloba-lanopsis glauca）在形成菌根过程中不同阶段的菌根形态变化进行了研究,结果显示：用夏块菌孢子液接种青刚栎苗后,第14天起开始形成淡乳色的外生菌根,外延菌丝刚毛状;第一至第二个月可形成黄褐色、褐色外生菌根,外延菌丝刚毛或羊毛状。外生菌根为单根,长1～4mm,直径150～250μm。菌套厚12～20μm,平坦或自菌根延伸出刚毛状菌丝,外延菌丝束黄绿色;哈替氏网菌丝直径1～1.5μm。菌根老化后变暗褐或萎缩。外延菌丝束呈黄绿色是夏块菌菌根区别于其它块菌菌根最重要的形态特征。     

Interactions of green or red light with blue light on the dark closure of Albizzia pinnules

The interactions of green or red light with blue light on the dark closing of Albizzia julibrissin Durazz. pinnules have been investigated. Irradiations at 430, 450 and 470 nm progressively delay dark closing with increasing photon fluence rates. Red or green light alone has no effect. However, when the blue fluence rate is low, both red and green light interact with it and increase the delaying effect of the blue light. When the blue fluence rate is high, green light interacts with it to negate some of the effectiveness of the blue light, while red light has no effect. This is similar to results obtained previously with far-red light. It is suggested that the same unidentified photoreceptor is operating in both the far-red and blue regions. The results also indicate the presence of a blue-only absorbing photoreceptor whose action is increased by phytochrome.     

Effects of light quality on the physiology and the ecology of planktonic green sulfur bacteria in lakes

The effect of light quality on the selection of natural populations of Green Sulfur Bacteria (Chlorobiaceae) is considered to be a classic factor in the determination of their ecological niches. From the comparison among phototrophic bacterial populations of lakes, it is shown that brown and green pigmented groups of Chlorobiaceae have a differential distribution depending on depth. Statistical analyses prove that green species, which dominate at shallow oxic/anoxic boundaries, are correlated to light spectra enriched in long wavelengths, while brown ones are found when light spectra are enriched in the central region of the spectrum, as in deeper lake layers. Physiological experiments have been made withChlorobium limicola andC. phaeobacteroides cultures placed under different light quality conditions, in order to verify these hypotheses made on a field data basis. Results show that red and white light has more positive effects on the green bacterium than on the brown. Blue and green light illuminations have opposite consequences. Therefore, the effect of shallow depths and Chromatiaceae shading—which also increases the proportion of long wavelengths in light spectra—benefits the bacteriochlorophyll-based strategies of green species. On the other hand, the carotenoid-based strategies of brown ones are favored by the light climates usually dominant at greater depths. Thus, brown species are considered to be singular adaptations of Chlorobiaceae to depth, where bacteriochlorophyll light-harvesting is strongly limited by light quality.     

纽绵蚧跳小蜂在蚧虫体内发育的形态观察(膜翅目:跳小蜂科)

通过解剖皱大球坚蚧Eulecanium kuwanai Kanda雌成虫, 对寄生在其内的纽绵蚧跳小蜂Encyrtus sasakii Ishii的各个虫期的形态特征进行了观察比较,并做了显微拍照。结果显示,纽绵蚧跳小蜂一年发生一代,以蛹在寄主体内越冬。除虫体由龄期引起的个体差异外,纽绵蚧跳小蜂的一、二龄幼虫腹部末端都具有长形通气柄,到第三、四龄期其通气柄变为尾囊状构造。成虫期的雌性小蜂中胸小盾片为黄色,前翅淡烟色并有一个暗斑,上密生黑色粗毛;雄性的为黑色,前翅色淡,无暗斑。     

Fine structural analysis of the thoracic longitudinal stripes of Zaprionus vittiger (Diptera)

The structure of the longitudinal zebra stripes on the thorax of adult Zaprionus vittiger has been investigated by light-, polarization-, transmission electron-, and scanning electron microscopy. Each stripe consists of a central white stripe of about 50 μm width and two lateral dark brown stripes about 30 μm wide. Three different types of trichomes occur: Very long bent trichomes of the grooved-type, long bent trichomes of the crested-type, and short straight trichomes. The central white stripe contains neither bristle organs nor short straight trichomes but carries many long bent trichomes most of which are of the grooved type, contain two cavities and polarize the light in the polarization microscope. The dark brown stripes carry bristle organs and many trichomes of the short and straight-type. Bent trichomes of the crested-type are found on the whole zebra stripe at about equal frequencies; they contain no cavities and do not polarize the light. The cuticle of the dark stripes is underlain by pigment cells. It is suggested that the pigment granules in the epidermal cells cause the dark color of the dark brown stripes, whereas the form and structure of the bent grooved type trichomes cause the white color of the central stripe.     

Description and identification of two new diseases of guariroba palm (Syagrus oleraceae) in Brazil

Guariroba is a palm species native to central Brazil. Seedlings of guariroba with leaf spots of unknown aetiology were found in Patos de Minas, Minas Gerais, Brazil. The leaf spots were manifest as two different symptom types: the first lesion type consisted of necrotic spots with a rounded to elongate shape, with a light colour and dark edges; the second lesion type had a rounded shape, was dark brown in colour with a light brown edge. The objective of this study was to elucidate the aetiology of both diseases. The likely causal agents were isolated and Koch's postulate fulfilled. Subsequently, the ITS region of rDNA from both micro‐organisms were amplified and sequenced. According to the morphological characteristics and molecular analyses, the fungal species were identified as Pestalotiopsis adusta (causing necrotic spots with a rounded to elongate shape, with a light colour and dark edges), and Alternaria tenuissima (causing lesions with a rounded shape, dark brown in colour with a light brown edge). Identification of the causal organisms of these two diseases will help guide management approaches that might be tested to reduce impact of the disease on Guariroba, including the use of fungicides and cultural approaches.     

Absorption of visible spectrum radiation by the wing membranes of living pteropodid bats

The wing membranes of bats present a large surface area upon which radiation might be taken up, increasing heat load to the animals. This, combined with the high amount of heat produced during flight, has been advanced as one hypothesis explaining the fact that bats are almost exclusively nocturnal. The proportion of short-wave (visible) radiation absorbed by bat wing membrane has previously been measured at between 0.7 and 0.92. These measurements were made on pieces of membrane taken from the wings of dead, mainly insectivorous bats from temperate regions. Here we examined the amount of light transmitted through and reflected off the wing membranes of four species of live pteropodid bats. There were significant differences in wing reflection between species. At 0.68, the average proportion of light absorbed into the wing membranes was lower than previously reported. This might be because we worked with live animals or because ours were tropical bats which are routinely exposed to tropical sun when roosting. Variation in wing tension strongly affected light absorption. It was predicted that the relaxed state of wing membrane through part of the wing beat cycle would increase the absorption of light into the wings of day-flying bats. The proportion of light absorbed into wings was shown to be an important factor in the heat balance of hypothetical bats flying during the day. Our results raise the predicted temperature at which bats flying during the day might experience hyperthermia by approximately 2 °C and suggest that variation in albedo of wings between species may make some species more susceptible to overheating than others. Accepted: 6 December 1998     

中国安徽瘦腹水虻一新种记述(双翅目,水虻科,瘦腹水虻亚科)

记述了安徽黄山风景名胜区瘦腹水虻属Sargus Fabricius,17981新种,黄山瘦腹水虻Sargus huangshanensis sp.nov.。详细描述了其形态特征,并绘制了其主要鉴别特征图,所有标本均保存在贵州大学昆虫研究所。     

Photosynthesis of Marine Macroalgae from Antarctica: Light and Temperature Requirements

The photosynthetic performance of macroalgae isolated in Antarctica was studied in the laboratory. Species investigated were the brown algae Himantothallus grandifolius, Desmarestia anceps, Ascoseira mirabilis, the red algae Palmaria decipiens, Iridaea cordata, Gigartina skottsbergii, and the green algae Enteromorpha bulbosa, Acrosiphonia arcta, Ulothrix subflaccida and U. implexa. Unialgal cultures of the brown and red algae were maintained at 0°C, the green algae were cultivated at 10°C. I_K values were between 18 and 53 μmol m^?2 s^?1 characteristic or low light adapted algae. Only the two Ulothrix species showed higher I_K values between 70 and 74 μmol m^?2 s^?1. Photosynthesis compensated dark respiration at very low photon fluence rates between 1.6 and 10.6 μmol m^?2 s^?1. Values of α were high: between 0.4 and 1.1 μmol O₂ g^?1 FW h^?1 (μmol m^?2 s^?1)^?1 in the brown and red algae and between 2.1 and 4.9 μmol O₂ g^?1 FW h^?1 (μmol m^?2 s^?1)^?1 in the green algal species. At 0°C P_max values of the brown and red algae ranged from 6.8 to 19.1 μmol O₂ g^?1 FW h^?1 and were similarly high or higher than those of comparable Arctic-cold temperate species. Optimum temperatures for photosynthesis were 5 to 10°C in A. mirabilis, 10°C in H. grandifolius, 15°C in G. skottsbergii and 20°C or higher in D. anceps and I. cordata. P: R ratios strongly decreased in most brown and red algae with increasing temperatures due to different Q₁₀ values for photosynthesis (1.4 to 2.5) and dark respiration (2.5 to 4.1). These features indicate considerable physiological adaptation to the prevailing low light conditions and temperatures of Antarctic waters. In this respect the lower depth distribution limits and the northern distribution boundaries of these species partly depend on the physiological properties described here.     

Effects of light on pigment development in the echiuran worm, Bonellia viridis

In rhe echiuran Bonellia viridis the green pigment first develops in the gastrula, before the formation of the trochal rings, and the trochophores acquire a deep green pigmentation before hatching. Eggs that were cultured under continuous illumination (2000–4000 lx) did not develop any green pigment, and although the trochophores hatched normally, they lacked pigment entirely. The unpigmented trochophores that were kept under continuous illumination developed into unpigmented males and females. The far-blue (380–400 nm) and red (620–640 nm) regions were more effective in preventing pigment development than the blue, green and yellow regions of the spectrum. Illumination of the eggs before the gastrula stage did not affect the development of pigment when these were subsequently returned to the dark. When unpigmented trochophores, that had been cultured in the light, were placed in the dark they acquired a slight pigmentation, but this was much less intense than that of trochophores that had been cultured in the dark throughout. Pigmented trochophores were more vulnerable to high light intensities than unpigmented ones.     

Histology,ultrastructure, and pigmentation in the horny scales of growing crocodilians

Alibardi L. 2011. Histology, ultrastructure, and pigmentation in the horny scales of growing crocodilians. —Acta Zoologica (Stockholm) 92 : 187–200. The present morphological study describes the color of hatchling, juvenile, and adult crocodilian skin and the origin of its pigmentation. In situ hybridization and immunostaining indicate that crocodilian scales grow as an expansion of the proliferating epidermis of the hinge region that form thin lateral rings. In more central areas of growing scales, new epidermal layers contribute to increase the thickness of the stratum corneum. The dark pigmentation and color pattern derive from the different distribution of epidermal and dermal chromatophores. The more intensely pigmented stripes, irregular patches and dot‐like spots, especially numerous in dorsal scales, derive from the incorporation of the eumelanosomes of epidermal melanocytes in differentiating beta cells of the epidermis. Dermal melanophores, mainly localized in the loose upper part of the dermis, also contribute to the formation of the dark or gray background of crocodilian scales. The eumelanosomes of dermal melanophores determine the darkening of the skin pattern in association with the epidermal melanocytes. Iridophores are infrequent, while xantophores are present in the species analyzed with a sparse distribution in the superficial dermis among melanophores. The presence of xantophores and of the few iridophores in areas where epidermal melanocytes are absent appear to determine the brown or the light yellow‐orange background observed among the darker regions of crocodilian scales.     

Morphometrical evolution in a Drosophila clade: the Drosophila obscura group

Five morphometrical traits (wing and thorax length, ovariole number, and thoracic and female abdomen pigmentation) were investigated in laboratory stocks of 20 species belonging to the Drosophila obscura group (subgenus Sophophora). These species originated from four biogeographical regions and represent all five of the presently recognized, taxonomic subgroups. Size‐related traits (wing and thorax length) were highly variable across species, and interspecific variation explained more than 90% of total variability. In both traditional and phylogenetic analyses, wing size was positively correlated with latitude of origin. These interspecific correlations were however notably weaker than those for intraspecific correlations. Wing/thorax ratio, which may be related to flight capacity, showed little variation. Ovariole number was highly variable (range 27–53) both within and between species, and was positively correlated with the wing/thorax ratio, suggesting that species with relatively large ovaries have relatively low wing loading. Although many species are completely dark, 11 had some regions of light coloration. A light thorax with a median darkening was observed in six species. A variable pigmentation of abdominal tergites, in females only, was found in nine species, belonging to three subgroups only. With respect to both molecular phylogeny and morphometrical evolution, the D. obscura subgroup is probably now the best investigated clade in Drosophila.     

Influence of ambient light on the evolution of colour signals: comparative analysis of a Neotropical rainforest bird community

Rainforests offer two contrasted light environments: a bright canopy rich in blue and UV and a dark understorey, rich in green and orange. Therefore, natural selection for crypsis should favour dark brown signals in understorey and bright green signals in canopy, whereas sexual selection for conspicuousness should favour bright yellow‐red signals in understorey and dark blue and UV signals in canopy. Using spectrometry and comparative analyses, we examined the relationship between ambient light and colour signals in a bird community of French Guiana. It appears that brightness and hue are mostly naturally selected, while UV content of plumage is more likely sexually selected. At each height, both sexes present similar coloration but males display more conspicuous sexually selected patterns than females. These results show that ambient light drives the evolution of colour signals at community scale, and should be considered when studying signalling in other communities and light‐contrasted ecosystems.     

Ficus rubiginosa 'variegata', a chlorophyll-deficient chimera with mosaic patterns created by cell divisions from the outer meristematic layer

BACKGROUND AND AIMS: Sections leaves of Ficus rubiginosa 'Variegata' show that it is a chimera with a chlorophyll deficiency in the second layer of the leaf meristem (GWG structure). Like other Ficus species, it has a multiseriate epidermis on the adaxial and abaxial sides of the leaf, formed by periclinal cell divisions as well as anticlinal divisions. The upper and lower laminae of the leaf often exhibit small dark and light green patches of tissue overlying internal leaf tissue. METHODS: The distribution of chlorophyll in transverse sections of typical leaves was determined by fluorescence microscopy. KEY RESULTS: Patches of dark and light green tissue which arise in the otherwise colourless palisade and spongy mesophyll tissue in the entire leaf are due to further cell divisions arising from the bundle sheath which is associated with major vascular bundles or from the green multiseriate epidermis. Leaves produced in winter exhibit more patches of green tissue than leaves which expand in mid-summer. Many leaves produced in summer have no spotting and appear like a typical GWG chimera. There is a strong relationship between the number of patches on the adaxial side of leaves and the number on the abaxial side, showing that the cell division in upper and lower layers of leaves is strongly coordinated. In both winter and summer, there are fewer patches on the abaxial side of leaves compared with the adaxial side, indicating that periclinal and anticlinal cell divisions from the outer meristematic layer are less frequent in the lower layers of leaf tissue. Most of the patches are small (<1 mm in longest dimension) and thus the cell divisions which form them occur late in leaf development. Leaves which exhibit large patches generally have them on both sides of the leaves. CONCLUSION: In this cultivar, the outer meristematic layer appears to form vascular bundle sheaths and associated internal leaf tissue in the entire leaf lamina.     

Interactions of environmental factors influencing pupal coloration in swallowtail butterfly Papilio xuthus

The swallowtail butterfly Papilio xuthus Linné [Lepidoptera: Papilionidae] exhibits pupal protective color polyphenism. Interactions of various environmental factors on pupal coloration were analyzed in non-diapausing individuals. Under sufficient light (200lux), most pupating larvae became green pupae when the surface of the pupation site was smooth, while they became brown when the surface was rough. Tactile signals are the positive environmental factors causing induction of the brown pupal coloration. In dark boxes, the induction of the brown pupal coloration was easily induced even on a smooth surface, suggesting that light suppresses induction of brown coloration. Different colors of pupation sites did not affect pupal coloration under sufficient light. Environmental factors received during a critical period both before girdling and after girdling affected pupal coloration. When tactile signals received from rough surfaces reach threshold levels during pupation, brown pupal coloration is determined. Larvae reared under a daily periodicity of natural light formed a girdle at midnight, subsequently, the prepupae received strong daylight the following day. Under natural light most larvae produced brown pupae on rough surfaces and green pupae on smooth surfaces.     

The effect of colour of the substrate on the landing and oviposition behaviour of the cabbage root fly

Field and laboratory experiments were made in order to understand the relation between the spectral characteristic of a substrate and its attractiveness for Delia radicum (L.) (Diptera: Anthomyiidae) flies to land or oviposit. Landing females preferred substrates with high reflectance of green and particularly of yellow wavelengths, but substrates with a high proportion of the blue and green reflectance simultaneously (light blue and white) were also very attractive. Unattractive substrates had either low reflectance across the whole insect-visible spectrum (dark blue) or increased reflectance only in orange or red region of the spectrum (red) or a large proportion of UV reflectance (aluminium). Landing males were most attracted to the substrates with the highest total reflection. Oviposition attractiveness of a substrate grew with an increase in the proportion of reflectance in the blue and a decrease in the green regions of the spectrum. In addition, the oviposition attractiveness increased with increasing total reflection and contrast with the background, and decreased with a high proportion of UV reflectance.     

Color pattern formation on the wing of the butterfly Pieris rapae. 1. Cautery induced alteration of scale color and delay of arrangement formation

Experimental approaches to color pattern formation of lepidopteran insects have been made exclusively by analyzing pattern alterations in adult wings induced by operations. We microcauterized the presumptive black region of the dorsal forewing of the butterfly Pieris rapae and analyzed not only the resultant color pattern in the adult wing but also the cell behavior in the pupal wing epidermis around the injury. Cautery induced color alterations were as follows: (i) cautery up to 49.5 h after pupation resulted in white regions appearing within the black region while later cauteries induced larger white regions; (ii) cautery between 50 and 59.5 h resulted in the white regions induced by the cauteries being dramatically decreased; (iii) cautery after 60 h resulted in white regions that had almost disappeared. The examination of the cell behavior in the pupal wing epidermis after cauteries showed that the row formation of scale precursor cells was delayed. This delayed area varied with the time of cautery, in the same manner as that in the induced white area in the adult wing ((i) – (iii) above). The relationship between scale color alteration and the developmental delay of the scale row formation is discussed.