瓢虫的趋光性反应研究

以六斑月瓢虫Menochilus sexmaculata Fabricius和狭臀瓢虫Coccinella transversalis Fabricius为例,研究了瓢虫对不同光质(波长)的趋光性反应。在室内分别测定了六斑月瓢虫和狭臀瓢虫对5种发光二极管(LED)光波的趋性,以及在田间挂板(佳多)测定了瓢虫对色板的选择趋性。室内测定结果表明,瓢虫对黄色和白色LED光波的选择趋性显著高于与其它颜色;田间挂板试验表明,黄色对瓢虫的诱杀作用最强。综合分析,黄色对瓢虫有强烈的吸引作用,建议在使用黄板进行田间监测和防治时应考虑对天敌瓢虫的诱杀作用。     

Why do red and dark-coloured cars lure aquatic insects? The attraction of water insects to car paintwork explained by reflection-polarization signals

We reveal here the visual ecological reasons for the phenomenon that aquatic insects often land on red, black and dark-coloured cars. Monitoring the numbers of aquatic beetles and bugs attracted to shiny black, white, red and yellow horizontal plastic sheets, we found that red and black reflectors are equally highly attractive to water insects, while yellow and white reflectors are unattractive. The reflection-polarization patterns of black, white, red and yellow cars were measured in the red, green and blue parts of the spectrum. In the blue and green, the degree of linear polarization p of light reflected from red and black cars is high and the direction of polarization of light reflected from red and black car roofs, bonnets and boots is nearly horizontal. Thus, the horizontal surfaces of red and black cars are highly attractive to red-blind polarotactic water insects. The p of light reflected from the horizontal surfaces of yellow and white cars is low and its direction of polarization is usually not horizontal. Consequently, yellow and white cars are unattractive to polarotactic water insects. The visual deception of aquatic insects by cars can be explained solely by the reflection-polarizational characteristics of the car paintwork.     

Photomorphogenesis, photosynthesis, and seed yield of wheat plants grown under red light-emitting diodes (LEDs) with and without supplemental blue lighting

Red light-emitting diodes (LEDs) are a potential light sourcefor growing plants in spaceflight systems because of their safety,small mass and volume, wavelength specificity, and longevity.Despite these attractive features, red LEDs must satisfy requirementsfor plant photosynthesis and photomorphogenesis for successfulgrowth and seed yield. To determine the influence of galliumaluminium arsenide (GaAIAs) red LEDs on wheat photomorphogenesis,photosynthesis, and seed yield, wheat (Triticum aestivum L.,cv. ‘USU-Super Dwarf’) plants were grown under redLEDs and compared to plants grown under daylight fluorescent(white) lamps and red LEDs supplemented with either 1% or 10%blue light from blue fluorescent (BF) lamps. Compared to whitelight-grown plants, wheat grown under red LEDs alone demonstratedless main culm development during vegetative growth throughpreanthesis, while showing a longer flag leaf at 40 DAP andgreater main culm length at final harvest (70 DAP). As supplementalBF light was increased with red LEDs, shoot dry matter and netleaf photosynthesis rate increased. At final harvest, wheatgrown under red LEDs alone displayed fewer subtillers and alower seed yield compared to plants grown under white light.Wheat grown under red LEDs+10% BF light had comparable shootdry matter accumulation and seed yield relative to wheat grownunder white light. These results indicate that wheat can completeits life cycle under red LEDs alone, but larger plants and greateramounts of seed are produced in the presence of red LEDs supplementedwith a quantity of blue light. Key words: Triticum aestivum L., red light, blue light, subtillering, bioregenerative advanced life support     

Photomorphogenesis, photosynthesis, and seed yield of wheat plants grown under red light-emitting diodes (LEDs) with and without supplemental blue lighting

Red light-emitting diodes (LEDs) are a potential light source for growing plants in spaceflight systems because of their safety, small mass and volume, wavelength specificity, and longevity. Despite these attractive features, red LEDs must satisfy requirements for plant photosynthesis and photomorphogenesis for successful growth and seed yield. To determine the influence of gallium aluminium arsenide (GaAlAs) red LEDs on wheat photomorphogenesis, photosynthesis, and seed yield, wheat (Triticum aestivum L., cv. 'USU-Super Dwarf') plants were grown under red LEDs and compared to plants grown under daylight fluorescent (white) lamps and red LEDs supplemented with either 1% or 10% blue light from blue fluorescent (BF) lamps. Compared to white light-grown plants, wheat grown under red LEDs alone demonstrated less main culm development during vegetative growth through preanthesis, while showing a longer flag leaf at 40 DAP and greater main culm length at final harvest (70 DAP). As supplemental BF light was increased with red LEDs, shoot dry matter and net leaf photosynthesis rate increased. At final harvest, wheat grown under red LEDs alone displayed fewer subtillers and a lower seed yield compared to plants grown under white light. Wheat grown under red LEDs+10% BF light had comparable shoot dry matter accumulation and seed yield relative to wheat grown under white light. These results indicate that wheat can complete its life cycle under red LEDs alone, but larger plants and greater amounts of seed are produced in the presence of red LEDs supplemented with a quantity of blue light.     

An experimental test of a visual-based push–pull strategy for control of wood boring phytosanitary pests

1 International phytosanitary standards require mandatory fumigation for key wood boring beetle pests prior to export. Pressure to reduce the use of toxic fumigants has created a need for alternative control techniques.
2 A visual based push–pull strategy that exploits a differential attraction to yellow and ultra violet (UV) lights was tested for its efficacy at controlling Cerambycidae.
3 The relative attraction of four 'push' lighting treatments [two yellow (high and low-pressure Sodium), one white (metal halide) and a control (no light)] to beetles was assessed. Highly attractive UV 'pull' traps were compared with a paired control trap, the difference used as a measure of the UV traps attractiveness to residual beetles attracted by 'push' lights.
4 Trap catch beneath the two yellow 'push' lights was more similar to the control (no light) treatment than the white light for both species. Control 'push' lights had the highest average catch of Arhopalus ferus , whereas white light was least attractive. This finding was counter intuitive to expectations, and potential mechanisms are discussed. The white 'push' light was most attractive to Prionoplus reticularis.
5 Ultraviolet 'pull' traps were highly attractive to residual beetles drawn to yellow 'push' light treatments. Relative attraction to the UV 'pull' traps beneath control and white 'push' lights differed between species.
6 The results obtained suggest that a push–pull strategy combining yellow site lighting with UV kill traps could provide site specific control of wood borers. Future research should attempt large-scale trials that are subject to competing alternative stimuli at a wood processing site.     

Blue–green opponency and trichromatic vision in the greenhouse whitefly (Trialeurodes vaporariorum) explored using light emitting diodes

Visual orientation in the greenhouse whitefly (Trialeurodes vaporariorum Westwood, Hemiptera: Aleyrodidae) is the result of “wavelength‐specific behaviours.” Green–yellow elicits “settling behaviour” while ultraviolet (UV) radiation initiates “migratory behaviour.” The only available physiological study of the photoreceptors' spectral efficiency showed peaks in the green and the UV range and whitefly vision was said to be dichromatic so far. In order to study the visual behaviour of T. vaporariorum, 19 narrow‐bandwidth light emitting diodes (LEDs) covering the UV‐A and visible range were used in combination with light scattering acrylic glass screens in a small‐scale choice arena under greenhouse conditions. Multiple‐choice and dual‐choice assays were performed, resulting in LED‐based behavioural action spectra of settling (green) and migratory behaviour (UV). A potential inhibitory blue–green chromatic mechanism was studied by combining yellow with different bluish LEDs. Intensity dependencies were illustrated by changing LED intensities. Regarding the “settling response,” highest attraction was achieved by a green LED with a centroid wavelength of 550 nm, while a blue LED with 469 nm proved to be most inhibitory. Besides this inhibitory interaction, an intensity dependence was observed within the action spectrum in the green–yellow range. “Migratory behaviour” was elicited the most by the UV LED with the shortest available wavelength of 373 nm. The results provide compelling behavioural evidence for the presence of a green and a yet undescribed blue sensitive photoreceptor and a blue–green opponent mechanism. Furthermore, empirical colour choice models were built and receptor peaks were estimated around 510–520 nm (green), 480–490 nm (blue) and 340–370 nm (UV). Consequently, a trichromatic receptor setup is suggested for T. vaporariorum.     

光质对紫背天葵生长、次生代谢和抗氧化胁迫的影响

以紫背天葵为供试材料,采用LED灯精量调控光质和光强,研究相同光照强度(350±5 μmol·m^-2·s^-1)下,白光(W)、红光(R)、蓝光(B)、黄光(Y)、红蓝混合光(RB)、红蓝黄混合光(RBY)对紫背天葵生长、次生代谢和氧化胁迫抗性的影响.结果表明:与白光(W)相比,红光(R)能够显著促进紫背天葵植株的生长以及干物质和可溶性糖含量的积累;而蓝光(B)则抑制紫背天葵的生长;叶绿素含量在有色光处理下均显著降低;虽然红蓝黄混合光(RBY)未能显著提升紫背天葵的干物质含量,但总酚、类黄酮和花青素含量显著提升,这些还原态物质的积累有利于提高紫背天葵的抗氧化能力,在增强自身抗逆性的同时提升营养价值.本研究为光质调控紫背天葵的多样化生产提供了理论依据.     

不同波长光照对罗汉果光合及生长影响

罗汉果试管苗在不同波长的LED(半导体)蓝(475±5nm)、黄(585±5nm)、红(660±5nm)及普通日光灯下培养,25d后观测发现,其外观的优劣依次为:蓝光>白光>红光>黄光;植株重量:蓝光>红光>黄光>白光;蓝光和白光下的植株叶大、色绿,植株矮壮,侧芽多;红光和黄光下的植株叶小、色黄绿,植株高、细、弯曲、节间长。测定罗汉果成熟叶片的吸收光谱,发现在波长380~500nm及660~680nm处有较强吸收。不同的光质下测定成熟叶片光合速率,大小依次为:红光>蓝光>白光>黄光。上述的各项试验表明,蓝光对罗汉果幼苗生长发育最好;红光和蓝光为成熟叶片光合作用的最佳光源。     

Light emitting diode(LED)‐based trapping of the greenhouse whitefly (Trialeurodes vaporariorum)

Visual traps like yellow sticky card traps are used for monitoring and control of the greenhouse whitefly (Trialeurodes vaporariorum). However, reflected intensity (brightness) and hence, attractiveness depend on the ambient light conditions, and the colour (wavelength) might not fit with the sensitivity of whitefly photoreceptors. The use of light emitting diodes (LEDs) is a promising approach to increase the attractiveness, specificity and adaptability of visual traps. We constructed LED‐based visual traps equipped with blue and green high‐power LEDs and ultraviolet (UV) standard LEDs according to the putative spectral sensitivities of the insects' photoreceptors. In a series of small‐scale choice and no‐choice recapture experiments, the factors time of day as well as light intensity and light quality (colour) of LED traps were studied in terms of attractiveness compared to yellow traps without LEDs. Green LED traps (517 nm peak wavelength) were comparably attractive in no‐choice experiments but clearly preferred over yellow traps in all choice experiments. The time of day had a clear effect on the flight activity of the whiteflies and thereby on the trapping success. Blue LEDs (474 nm) suppressed the attractiveness of the light traps when combined with green LEDs suggesting that a yet undetected photoreceptor, sensitive for blue light, and an inhibiting interaction with the green receptor, might exist in T. vaporariorum. In choice experiments between LED traps emitting green light only or in combination with UV (368 nm), the green‐UV combination was preferred. In no‐choice night‐time experiments, UV LEDs considerably increased whitefly flight activity and efficacy of trapping. Most likely, the reason for the modifying effect of UV is the stimulating influence on flight activity. In conclusion, it seems that the use of green LEDs alone or in combination with UV LEDs could be an innovative option for improving attractiveness of visual traps.     

Responses of the blister beetle Hycleus apicicornis to visual stimuli

Insect attraction to host plants may be partly mediated by visual stimuli. In the present study, the responses of adult Hycleus apicicornis (Guér.) (Coleoptera: Meloidae) to plant models of different colours, different combinations of two colours, or three hues of blue of different shapes are compared. Single‐colour models comprised the colours sky blue, bright green, yellow, red, white and black. Sky blue (reflecting light in the 440–500 nm region) is the most attractive, followed by white, which reflects light over a broader range (400–700 nm). On landing on sky blue targets, beetles exhibit feeding behaviour immediately. When different hues of blue (of different shapes) are compared, sky blue is preferred over turquoise, followed by dark blue, indicating that H. apicicornis is more attracted to lighter hues of blue than to darker ones. No significant differences are found between the three shapes (circle, square and triangle) tested, suggesting that reflectance associated with colour could be a more important visual cue than shape for host location by H. apicicornis. The preference of H. apicicornis for sky blue can be exploited in designing an attractive trap for its management.     

Tuning the white light spectrum of light emitting diode lamps to reduce attraction of nocturnal arthropods

Artificial lighting allows humans to be active at night, but has many unintended consequences, including interference with ecological processes, disruption of circadian rhythms and increased exposure to insect vectors of diseases. Although ultraviolet and blue light are usually most attractive to arthropods, degree of attraction varies among orders. With a focus on future indoor lighting applications, we manipulated the spectrum of white lamps to investigate the influence of spectral composition on number of arthropods attracted. We compared numbers of arthropods captured at three customizable light-emitting diode (LED) lamps (3510, 2704 and 2728 K), two commercial LED lamps (2700 K), two commercial compact fluorescent lamps (CFLs; 2700 K) and a control. We configured the three custom LEDs to minimize invertebrate attraction based on published attraction curves for honeybees and moths. Lamps were placed with pan traps at an urban and two rural study sites in Los Angeles, California. For all invertebrate orders combined, our custom LED configurations were less attractive than the commercial LED lamps or CFLs of similar colour temperatures. Thus, adjusting spectral composition of white light to minimize attracting nocturnal arthropods is feasible; not all lights with the same colour temperature are equally attractive to arthropods.     

Light emitting diodes increase phenolics of buckwheat (Fagopyrum esculentum) sprouts

Abstract

Four types of light emitting diodes (LEDs) were used in three combinations (all blue [BBB], red: blue: far-red [RBFr]=4:1:1 and red: green: blue [RGB]=4:1:1) and seven irradiation cycles (12 h/12 h photoperiod, 1 Hz, 10 Hz, 100 Hz, 1 KHz, 10 KHz and 100 KHz) were applied to examine their effect on growth, stem color and phenolic compounds (homoorientin, orientin, rutin, vitexin and isovitexin) in buckwheat (Fagopyrum esculentum cv. Great Ruby) sprouts. With a few exceptions, among all the combinations and irradiation cycles of LEDs, the Great Ruby cultivar showed significant differences in total height and dry weight of sprouts. The study revealed that there was a direct effect of different combination and irradiation cycles of LEDs on sprout height and dry weight; and among the combinations, RBFr and BBB had more positive effect than RGB. Increasing irradiation cycles markedly decreased the red color of stalks of F. esculentum cv. Great Ruby sprouts, with no significant effect on leaf color. In sprouts, the rutin content of leaves and stalks was higher at 12 h photoperiod and the amount in leaves was 5–7% higher than that of stalks in all combinations and irradiation cycles of LEDs. Among polyphenols, the rutin content in stalks was 1.45–2.97 mg g^?1 dry weight and the maximum amount of rutin was obtained from RGB combination of LEDs. In leaves, higher amounts of homoorientin, orientin and vitexin+isovitexin were obtained from the RGB combination and there were significant differences between RGB and other two combinations of LEDs. On the other hand, in between the irradiation cycles used in the study, there were no significant differences for other polyphenols in leaves and stalks of buckwheat sprouts.     

Field studies on colour preferences of Ctenarytaina thysanura in Tasmanian boronia farms

Field tests on attraction of Ctenarytaina thysanura (Hemiptera: Psyllidae) adults to different coloured 30×30 cm sticky traps revealed a preference for yellow. Among the enamel colours tested, more psyllids were captured on yellow traps followed by green, then blue and least on red, cyan and magenta. Dilution of yellow enamel with 50% white (1Y: 1W) and 75% white (1Y: 3W) to produce yellow-white hues resulted in a significant decrease in psyllid capture indicating that the psyllids response to yellow was one of positive attraction and could suggest true colour discrimination. Reflectance spectra of painted surfaces of the enamel colours and also yellow to white hues indicated that psyllid capture rates were directly related to the proportion of light reflected in the 500–560 nm region. The biological basis of the observed C. thysanura response may be that yellow is the most intensely reflective colour in the general part of the spectrum for leaves which reflect most light in the 500–600 nm (peak 550 nm) range.     

Effect of light emitting diodes on the cultivation of Spirulina platensis using NPK‐10:26:26 complex fertilizer

NPK‐10:26:26 complex fertilizer based culture medium was studied for the mass production of Spirulina platensis using different light emitting diodes (LEDs). First, cultivation was carried out under white LED to formulate the optimum fertilizer loading for which Spirulina growth was maximized. Optimum composition for newly formulated fertilizer medium was NPK fertilizer ?0.76 g L^?1 and sodium bicarbonate ?10.0 g L^?1 and corresponding biomass productivity was found to be 76.67 mg L^?1 day^?1. The effect of different LEDs (for example, blue, white, red, green and yellow) on Spirulina growth kinetics and the accumulation of chlorophyll, protein and lipid content was determined using the optimum NPK fertilizer medium. Kinetic parameters (i.e., biomass productivity, maximum specific growth rate, maximum biomass concentration, nitrogen‐to‐biomass conversion factor and phosphorus‐to‐biomass conversion factor) and chlorophyll accumulation were affected by the use of different LEDs and follow the following trend: blue > white > red > green > yellow, whereas protein and lipid accumulation was almost independent of LEDs used. Elemental C, N, P and K concentrations were measured to find the effects of nutrients for the growth of Spirulina platensis. Physicochemical parameters (pH and conductivity) were also monitored during biomass growth under different LEDs. Finally, biomass growth using NPK‐10:26:26 fertilizer under different LEDs was compared with standard Zarrouk medium and better growth results were obtained using optimally formulated NPK‐10:26:26 fertilizer medium.     

Spectral preference and temporal modulation of photic orientation by Colorado potato beetle on a servosphere

The Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), is a diurnal insect that strongly relies on visual cues to guide its walk. In the present study, we investigated the orientation behavior of non‐diapausing walking CPB in response to emissive colors produced by light emitting diodes (LEDs) in a dual choice arena adapted to a servosphere, where the only illumination available came from the photo‐stimuli. Our results demonstrate that CPB show positive phototactic behavior when stimulated with different wavelengths of light; they preferred to orient towards white (420–775 nm), ultraviolet (UV) (351 nm), blue (472 nm), green (570 nm), yellow (585 nm), orange (590 nm), and red (660 nm) over darkness when both alternatives were offered, but no orientation responses were elicited by infrared (940 nm). Both males and females preferred yellow and green over other colors, but did not show any particular preference between them, thus correlating with their preference for wavelengths reflected by vegetation. Sexual differences were noted in that male CPB preferred white over either red or UV, whereas female CPB did not show any preferences when offered these colors. Female CPB preferred UV and blue over red, whereas males showed no preferences when these colors were offered. Colorado potato beetles turned at higher angles and performed more tortuous walks in complete darkness and when infrared vs. darkness were offered compared with the rest of the colored lights. Both sexes preferred continuous over pulsed yellow light. Colorado potato beetles subjected to pulsed yellow light showed a temporal alteration of their walking performance by walking less, slower, and turning at a higher rate. The results are discussed with regard to the role of color in the CPB attraction to host plants and conspecifics as well as the role of intermittent photic stimuli in their orientation behavior. The information provided here provides a basis for the improvement of trapping devices for detection and survey of incipient or invasive CPB, and development of alternate control strategies for this important pest of potatoes and other solanaceous crops.     

Ultraviolet and violet light: attractive orientation cues for the Indian meal moth, Plodia interpunctella

The Indian meal moth (IMM), Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), engages in long-distance or foraging flights in the twilight hours of the scotophase when blue light dominates the irradiance spectrum of the sky. We tested the hypothesis that IMM uses wavelengths of visible blue/violet light as orientation cues that trigger phototactic responses. In four-choice laboratory experiments, blue light (400–475 nm) was significantly more effective than green (475–600 nm), orange (575–700 nm), or red (590–800 nm) light in attracting males and mated females. In subsequent experiments that tested light emitting diodes (LEDs) emitting peak wavelengths in the blue/violet-light range, the 405-nm 'violet' LED was significantly more effective than the 435-, 450-, or 470-nm 'blue' LED in attracting males as well as virgin and mated females. In electroretinogram recordings, the 405-nm wavelength elicited significantly stronger receptor potentials from female and male eyes than the 350-nm (UV) wavelength, and in a behavioral experiment it significantly enhanced the known attractiveness of UV light. Equal attraction of IMMs to 405-nm LEDs at 600–700 µW/cm² with or without UV light, and significantly stronger attraction to a 405-nm LED than to a 350-nm LED at maximum light intensities, suggest that the deployment of violet instead of UV light could become one of several management tactics for control of IMMs.     

Blue Light Reception in Phycomyces: Red Light Sensitization in madC Mutants

Sporangiophores of the zygomycete fungus Phycomyces blakesleeanus are sensitive to near UV and blue light. The quantum effectiveness of yellow and red light is more than 6 orders of magnitude below that of near UV or blue light. Phototropism mutants with a defect in the gene madC are about 10⁶ times less sensitive to blue light than the wild type. These mutants respond, however, to yellow and red light when the long wavelength light is given simultaneously with actinic blue light. In the presence of yellow or red light the photogravitropic threshold of madC mutants is lowered about 100-fold though the yellow and the red light alone are phototropically ineffective. A step-up of the fluence rate of broad-band red light (> 600 nm) from 6 × 10^?3 to 6W m^?2 elicits, in mutant C 148 madC, a transient deceleration of the growth rate. The growth rate of the wild type is not affected by the same treatment. The results are interpreted in terms of a red light absorbing intermediate of the blue light photoreceptor of Phycomyces. The intermediate should be short-lived in the wild type and should accumulate in madC mutants.     

Effects of light quality on growth and development of protocorm-like bodies of <Emphasis Type="Italic">Dendrobium officinale</Emphasis> in vitro

The effect of light quality on protocorm-like bodies (PLBs) of Dendrobium officinale was investigated. PLBs of D. officinale were incubated under a number of different light conditions in vitro, namely: dark conditions; fluorescent white light (Fw); red light-emitting diodes (LEDs); blue LEDs; half red plus half blue [RB (1:1)] LEDs; 67% red plus 33% blue [RB (2:1)] LEDs; and 33% red plus 67% blue [RB (1:2)] LEDs. Growth parameters, number of shoots produced per PLB, chlorophyll concentration and carotenoid concentration were measured after 90 days culture. The percentage of PLBs producing shoots was 85% under blue LEDs. In contrast, the percentage of PLBs producing shoots was less than 60% under dark conditions, fluorescent white light and red LEDs. The number of shoots produced per PLB was more than 1.5 times greater under blue LEDs, RB (1:1) LEDs and RB (1:2) LEDs than those cultured under other light treatments [dark, Fw, red LEDs and RB (2:1)]. Chlorophyll and carotenoid concentrations were significantly higher under blue LEDs and different red plus blue LED ratios, compared to other light treatments (dark, Fw and red LEDs). Blue LEDs, Fw, and RB (1:2) LEDs produced higher dry matter accumulations of PLBs and shoots. This study suggests that blue LEDs or RB (1:2) LEDs could significantly promote the production of shoots by protocorm-like bodies of D. officinale and increase the dry matter of PLBs and the accumulation of shoot dry matter in vitro.     

ACCLIMATION OF THE PHOTOSYNTHETIC APPARATUS OF PALMARIA PALMATA (RHODOPHYTA) TO LIGHT QUALITIES THAT PREFERENTIALLY EXCITE PHOTOSYSTEM I OR PHOTOSYSTEM II1

Acclimation of the photosynthetic apparatus to light absorbed primarily by phycobilisomes (which transfer energy predominantly to photosystem II) or absorbed by chlorophyll a (mainly present in the antenna of photosystem I) was studied in the macroalga Palmaria palmata L. In addition, the influence of blue and yellow light, exciting chlorophyll a and phycobilisomes, respectively, ivas investigated. All results were compared to a white light control. Complementary chromatic adaptation in terms of an enhanced ratio of phycoerythrin to phycocyanin under green light conditions was observed. Red light (mainly absorbed by chlorophyll a) and green light (mainly absorbed by phycobilisomes) caused an increase of the antenna system, which was not preferentially excited. Yellow and blue light led to intermediate states comparable to each other and white light. Growth was reduced under all light qualities in comparison to white light, especially under conditions preferably exciting phycobilisomes (green light-adapted algae had a 58% lower growth rate compared to white light-adapted algae). Red and blue light-adapted algae showed maximal photosynthetic capacity with white light excitation and significantly lower values with green light excitation. In contrast, green and yellow light-adapted algae exhibited comparable photosynthetic capacities at all excitation wavelengths. Low-temperature fluorescence emission analysis showed an increase of photosystem II emission in red light-adapted algae and a decrease in green light-adapted algae. A small increase of photosystem I emission teas also found in green light-adapted algae, but this was much less than the photosystem II emission increase observed in red light-adapted algae (both compared to phycobilisome emission). Efficiency of energy transfer from phycobilisomes to photosystem II was higher in red than in green light-adapted algae. The opposite was found for the energy transfer efficiency from phycobilisomes to photosystem I. Zeaxanthin content increased in green and blue light-adapted algae compared to red, white, and yellow light-adapted algae. Results are discussed in comparison to published data on unicellular red algae and cyanobacteria.     

Effects of colours and synthetic odours on the attraction of Glossina pallidipes and G. morsitans morsitans to traps and screens

ABSTRACT. Glossina morsitans morsitans Westw. and G. pallidipes Aust. flying around and landing on coloured screens and traps were sampled using electrocuting nets. External colour affected both attractiveness and efficiency of traps, such that yellow and green traps were unattractive and inefficient; black and red, attractive and inefficient; white, moderately attractive, and very efficient; and blue traps, attractive and efficient. The order of attractiveness of coloured screens was similar to that for traps. Landing responses were generally strongest on black surfaces, and weakest on white, but the results for blue were variable. Carbon dioxide and acetone odours improved trap catches and also eliminated most catch differences between traps differently coloured on their outer surfaces. The relative performances of traps coloured differently on inside surfaces only were not affected significantly by these odours, and in all cases black or red target areas inside the trap were required for optimum trap performance. When acetone and 1-octen-3-ol odours were used, catches were improved but the relative performance of differently coloured traps and screens was not changed. There were no obvious species differences in colour responses although numbers of G. morsitans were too low for statistical comparisons.