The interaction of innate and imposed colour perception: a behavioural approach

Nile tilapia were raised from eggs to 2 months of age under a coloured light regime (violet, blue, green, yellow, and red) and then tested for colour preference in a multiple chamber maze with different colour options. Fish were observed individually during three days at 8, 11, 14, and 17 h, every 2 min for 20 min and the visit frequency in each compartment was analyzed. Young Nile tilapia kept under yellow and red light showed preference for yellow and red, respectively. Fish held under violet, blue, and green light did not show any colour preference or avoidance. These results imply that environmental colour affects colour preference of Nile tilapia, possibly due to light-dependent shift of visual pigments in the retina, indicating that colour preference is not an innate response. This conclusion reinforces the idea that environmental colour modulates fish physiological and behavioural processes.     

Effect of colour of drugs: systematic review of perceived effect of drugs and of their effectiveness.

OBJECTIVE: To assess the impact of the colour of a drug''s formulation on its perceived effect and its effectiveness and to examine whether antidepressant drugs available in the Netherlands are different in colour from hypnotic, sedative, and anxiolytic drugs. DESIGN: Systematic review of 12 published studies. Six studies examined the perceived action of different coloured drugs and six the influence of the colour of a drug on its effectiveness. The colours of samples of 49 drugs affecting the central nervous system were assessed using a colour atlas. MAIN OUTCOME MEASURES: Perceived stimulant action versus perceived depressant action of colour of drugs; the trials that assessed the effect of drugs in different colours were done in patients with different diseases and had different outcome measures. RESULTS: The studies on perceived action of coloured drugs showed that red, yellow, and orange are associated with a stimulant effect, while blue and green are related to a tranquillising effect. The trials that assessed the impact of the colour of drugs on their effectiveness showed inconsistent differences between colours. The quality of the methods of these trials was variable. Hypnotic, sedative, and anxiolytic drugs were more likely than antidepressants to be green, blue, or purple. CONCLUSIONS: Colours affect the perceived action of a drug and seem to influence the effectiveness of a drug. Moreover, a relation exists between the colouring of drugs that affect the central nervous system and the indications for which they are used. Research contributing to a better understanding of the effect of the colour of drugs is warranted.     

颜色对梨小食心虫产卵选择性的影响

梨小食心虫(Grapholitha molesta Busck)是一种重要的果树害虫,早春产卵喜在桃嫩梢叶上,为探明寄主颜色在其产卵选择中的作用,利用彩色卡纸模拟寄主颜色,室内比较了红、粉红、浅粉、橙黄、深黄、浅黄、青绿、深绿、浅绿、蓝、紫、褐色等12种不同颜色基质对其成虫产卵选择性的影响。结果发现:基质颜色对梨小食心虫的产卵选择性有显著影响,其产卵偏嗜浅黄和浅绿色,白色和黑色参比时其产卵选择率分别依次为68.9%、63.8%和64.1%、65.5%,蓝和浅粉色则表现一定的拒避作用,白色和黑色参比时其产卵选择率分别依次为47.7%、40.4%和47.2%、42.7%,且参比色对其产卵选择性影响差异显著。基质颜色对其产卵量亦有显著性影响,无论黑或白色参比,黄、绿颜色上的产卵量均较多,尤其是深黄、深绿和青绿色。基质颜色对1—7日龄梨小食心虫成虫的产卵选择性均有显著影响。白色参比时,2、3日龄蛾对浅绿和浅黄色的产卵选择率显著高于其他颜色;黑色参比时,2日龄时明显偏嗜浅绿色(79.7%),6日龄时明显偏嗜浅黄色(74.8%)。表明寄主颜色在梨小食心虫产卵场所选择中具有重要作用,为其卵期监测和防控中颜色应用乃至进一步揭示其产卵寄主选择机理提供了依据和参考。     

Air pollution fades the plumage of the Great Tit

1. Great Tits ( Parus major ) derive the carotenoid pigments for their yellow plumage via the prey items in their diet. Air pollution is known to affect the abundance of many forest insects, e.g. green caterpillars, which are an important source of food and pigments for tits. This study investigates whether air pollutants indirectly affected the intensity of the yellow colour in P. major plumage via the reduced access to carotenoid sources.
2. The intensity of the yellow colour in the plumage of P. major nestlings was scored and the relative abundance of green herbivorous larvae in territories around a polluting copper smelter in SW Finland was simultaneously measured.
3. Both the intensity of yellow colour in nestling plumage and caterpillar abundance increased with increasing distance from the pollution source. The colour intensity correlated significantly with the density of green herbivorous larvae in a territory.
4. Parus major nestlings were significantly heavier at distant sites than close to the pollution source which suggests that the future survival probability of pale nestlings may be lowered.
5. Young birds, after their first moult, were studied for the relationships between condition, size and plumage colour by the means of ptilochronology. The plumage colour intensity did not correlate with the size corrected width of the growth bars in fifth rectrix (condition at moult) but was correlated positively with the length of the rectrix (size).
6. The implications of colour change for survival and mate choice are discussed.     

Effects of ambient colour on colour preference and growth of juvenile rainbow trout Oncorhynchus mykiss (Walbaum)

Colour preference of individual juvenile rainbow trout Oncorhynchus mykiss was tested at 1 and 12° C, and also at 12° C after a 42 day growth experiment under white, blue, green, yellow or red ambient colour. All experiments were carried out under controlled laboratory conditions and the preference was assessed by the location of the fish in a preference tank with four chambers. Rainbow trout showed a preference for blue and green at 1° C and for green at 12° C. After the growth experiment the fish reared in blue tanks preferred blue and green but green was the most preferred colour for the fish reared in green, yellow and red tanks. Yellow and especially red chambers were avoided, irrespective of the ambient colour during the growth trial. The final mass of fish reared in the red aquaria was significantly smaller than that of the fish in green tanks. In addition, when the data of the preference tests were correlated with the data of the growth experiment using mean values of the four tested colours, a very good linear relationship was observed between the preference ( i.e. visit frequency in coloured compartments) and growth rate as well as food intake. When considering the results both from the preference and growth trials it is suggested that green is the best environmental colour for rearing juvenile rainbow trout while rearing in a red environment cannot be recommended.     

Monoamines and acetyl-cholinesterase in the pineal gland and habenula of the ferret

Summary A histochemical method for demonstrating amines by fluorescence showed that the pinealocytes of the ferret contained a high concentration of a yellow fluorophore (probably 5-HT). Numerous green-fluorescent (noradrenaline-containing) nerve fibres occurred around intrapineal blood vessels, between pinealocytes and in the N. conarii (which entered the gland caudally). A collection of neuron-like cells (the pineal ganglion) lay, surrounded by a meshwork of nerve fibres, in the posterior part of the pineal. Neither the cells nor the fibres of the pineal ganglion contained monoamines, but both showed the presence of acetyl-cholinesterase which otherwise was found in the pineal only in fibres which stretched from the ganglion towards the cranial pole of the gland. The medial habenular nucleus showed a remarkable perivascular green fluorescence not seen in the lateral habenular nucleus nor anywhere else in the adjacent diencephalon and brain stem. The cells and fibres of this nucleus also contained much acetyl-cholinesterase.Bilateral superior cervical ganglionectomy, or treating animals with reserpine, removed the green fluorescence from both pineal nerve fibres and the habenula. Ganglionectomy also resulted in a progressive alteration in the colour of the parenchymal fluorescence from yellow to green; the original yellow colour was restored by treating ganglionectomised animals with nialamide (a monoamine oxidase inhibitor). L-Dopa, 5-hydroxytryptophan or nialamide, alone or in combination, had no effect on the fluorescence of the nerve fibres or cells of the pineal, or on the habenula.These results are related to previous findings that pinealectomy or ganglionectomy prevents the acceleration by artificial light of oestrus in ferrets.     

Inheritance of fruit-coat colours in Trichosanthes anguina Linn.

Summary In Trichosanthes anguina Linn. (Cucurbitaceae), reciprocal crosses among three naturally occurring fruit-coat colour varieties (deep green, green and white) and two yellow fruit-coat colour mutants isolated in the M₁ generation showed that a multiple allelic series control the fruit-coat colours. In the F₂ generation the fruit-coat colours segregated in a monohybrid ratio with deep green dominant over green, yellow and white, green dominant over yellow and white, and yellow dominant over white. Two yellow fruit-coat colour mutants used in this study were isolated from X-ray- and EMS-treated populations of a white fruit-coat colour variety.     

The effect of temperature upon intensity of colour in the coronas of cut blooms of narcissus var. Soleil d'Or

Cut blooms of narcissus Soleil d'Or were subjected to constant temperatures ranging from 1.2° C. to 18.3° C. both in darkness and under illumination. The rate of opening of successive florets, the rate and final degree of colour development of the corona and subsequent display life were observed. Opening was negligible at 1.2° C. and 38 days were taken to open to five florets at 4.5° C. Full opening occurred in 4 days at 15.6° C. The change of colour of the corona from yellow to orange was negligible at 15.6° C, but final intensity of orange colour increased with decreasing temperatures. Temperature affected colour development both of opened and unopened florets, and after treatment at low temperature colour continued to develop when the blooms were removed to 18.3° C. The period of low-temperature treatment giving maximum colour development was 8 days. Artificial illumination of intensity 200 ft.-candles had little effect at 18.3° C. but it increased orange colouring at the lower temperatures. Increased orange colour whether at intermediate or low temperature was shown to be associated with a slight increase in the concentration of the total carotenoids, but more especially with greatly increased content of β-carotene which constituted approximately 10–20% of the total carotenoids.     

Taking care of patients--does it matter whether the physician is a woman?

Researchers have recently begun to compare male and female physicians'' attitudes toward patients, medical knowledge, and practice styles. Although women start medical school with more "humanistic views," the conservative effect of medical socialization on both male and female students attenuates these differences. While some studies suggested that men are more scientifically knowledgeable, recent studies showed no significant differences in physicians'' medical knowledge. Male and female physicians also had comparable diagnostic and therapeutic behavior. In the intimate world of physicians and patients, however, there were notable differences. Women physicians seemed better able to communicate sensitivity and caring to patients, which may account for the common perception that women are more caring and empathic physicians. Medical educators may wish to study more closely female physicians'' communication styles to identify these behaviors and inculcate them into all physicians.     

Analysing spectral data: comparison and application of two techniques

This study compares two different methods of condensing complex spectral data into interpretable indices or metrics of colour. Colour spectra were measured on standardized Munsell colour paint chips and estimates of the three fundamental components of colour (brightness, chroma and hue) were generated using principal component analysis (PCA) and segment classification (SC). We tested the accuracy of these techniques for generating colour component estimates from spectral data in four different 'colour classes' (red/orange, yellow/ green, green/blue, and blue/purple) and in an aggregate data set containing all measured spectra. We conclude that both analysis techniques will generally provide more information than more conventional colour assessment techniques. Neither technique was superior under all conditions; appropriateness of each technique depends on the system under study. Efficacy of both techniques depends on the variability present in the data set; greater variance in colour tends to reduce overall resolution. An application of tfiese techniques is also presented in which we characterize sex-specific differences in colour between different populations of the poecilliid fish, Limia perugia.     

On the histochemical differences of aldehyd-fuchsin positive material in the fibres of the hypothalamo-hypophyseal tract of Rana temporaria

Summary Using a modified Alcian blue/Alcian yellow method, differences in stainability in the fibres of the preoptic-hypophyseal tract of Rana temporaria were observed. Near the preoptic nucleus most of the fibres stained yellow, in the tract the fibres stained lightgreen or showed green inclusions on a yellow background, whereas at the fibre-endings a colour switch to blue-green was found. This colour switch was the most pronounced in the neural lobe, where the neurosecretion stained blue-green, whereas in the fibre-endings in the outer zone of the median eminence a colour switch to green was noticed.The results can best be explained with the assumption that a modification or transformation of the neurosecretion occurs during its transport from the preoptic nucleus to the fibre-endings.Literature related to this hypothesis is discussed.     

Apostasy and selection for crypsis in the marine snail Littoraria filosa: an explanation for a balanced colour polymorphism

The marine snail, Littoraria filosa, is polymorphic for shell colour, with yellow, brown, and pink morphs that correspond in both appearance and frequency to the predominant background colours of its habitat. Previous research on this polymorphism has found indirect evidence of apostatic selection and selection for crypsis by unknown agents, probably crabs, and direct evidence of selection for crypsis by the parasitoid fly Sarcophaga megafilosia. In the present study, we report on field experiments to investigate whether S. megafilosia and shell‐crushing predators exert apostatic selection on L. filosa. For S. megafilosia, seven experimental treatments containing yellow and brown snails in the proportions of 0.1, 0.2, 0.4, 0.5, 0.6, 0.8, and 0.9 of each colour were established on mangrove trees and used to separately quantify the proportions of each colour attacked on grey/brown trunks and yellow/green leaves. The results obtained confirmed an earlier finding of selection for crypsis, but only showed slight, but significant, anti‐apostatic selection by S. megafilosia. For shell‐crushing predators, seven experimental treatments containing yellow and brown snails in the proportions of 0.08, 0.17, 0.33, 0.50, 0.66, 0.83, and 0.92 were established on two types of trees that differed in their background proportions of brown and green: (1) trees which had been pruned of approximately 90% of their foliage and (2) unpruned trees. The results obtained showed both selection for crypsis and apostatic selection. Furthermore, a selectively neutral frequency for yellow L. filosa was found for each background, and was less on pruned trees than unpruned ones (and vice versa for brown L. filosa), which can therefore account for the maintenance of a colour polymorphism where the proportions of each morph tend to resemble and correspond in frequency to the colours of the background. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 62–71.     

Suitability of different fluorescent powders for mass-marking the Chrysomelid, Diabrotica virgifera virgifera LeConte

Abstract:  The Western Corn Rootworm, Diabrotica virgifera virgifera LeConte (Col., Chrysomelidae), is an invasive alien pest of maize, Zea mays , in Europe. The suitability of 14 fluorescent powders for mass-marking the adults was studied in laboratory and in field cages. The visual discrimination between remaining spots of each colour on the beetles was investigated under ultraviolet (UV) light, as well as their retention time and the influences of those colours on the beetle survival and flight take-off response. The two best recognizable orange colours (i.e. of Radiant Colour and of Fiesta Colours Swada) were proposed for field experiments in first priority, followed by an orange and a yellow (both Magruder Colour), another yellow (Fiesta) and a pink (Radiant), as all did not affect beetle survival and flight take-off response and were recognizable under UV light for at least 10 days in the field. In contrast, the colours yellow and green (Radiant), red and blue (Magruder), yellow (Ciba Geigy) and pink (Fiesta) were unsuitable, because they either quickly disappeared from the beetles or adversely affected beetle survival or flight take-off response. For mass releases with differently marked beetles, only the use of a single orange colour together with a single yellow colour or the use of a pink colour together with a yellow colour can be used since few spots can clearly be discriminated from each other under UV light.     

Impact of patient care appraisal on physician behaviour in the office setting

The effect of patient care appraisal on physicians'' management of patients'' problems was assessed. Sixteen family physicians were involved. The eight in the experimental group helped in the selection of two of the five disease conditions to be audited and in the generation of optimal criteria of care for two of the conditions. Participation in the generation of optimal criteria was followed by a significant improvement in the physicians'' behaviour, but involvement in the selection of the conditions to be audited caused no change. The patient care appraisal did not lead to significant improvement of physicians'' management of the conditions. In a second analysis, in which only essential criteria of care were considered, the physicians who participated in the patient care appraisal significantly improved their management of patients'' problems. However, participation in the selection of the conditions and in the generation of the criteria of care had no effect on their performance. Patient care appraisal is an effective tool in continuing medical education and leads to improvement in the quality of care, provided the process focuses on essential criteria of care.     

Understanding physicians' response to AIDS.

Attempts to comprehend physicians'' extreme reaction to AIDS (acquired immune deficiency syndrome) have met with great difficulty since the disease brings into question traditional norms and assumptions. As the medical profession struggles to develop guidelines and policies to help it deal with this disease, it can draw on very little systematic research on the effect of AIDS on physicians'' attitudes and practices. We suggest a framework developed from the literature on physicians'' and society''s response to other disorders that would provide a basis for organizing the ever-increasing amount of information on physicians and AIDS and would guide systematic research aimed at understanding and predicting physicians'' participation in the prevention and management of AIDS. Within this framework we consider how characteristics of the disease, elements of the health care system and physicians'' attitudes interact to influence clinical and personal practices. AIDS had led to new delineations of physicians'' responsibility, modification of prevailing beliefs about physician autonomy and thus a redefinition of the role of the physician in North America.     

Antibiotics: no panacea.

Indicator conditions were used to evaluate the quality of 686 episodes of care provided in two emergency departments and in five family physicians'' offices. Overall, the care was considered adequate in 53% of the emergency department cases and in 40% of the cases dealt with in family physicians'' offices, the difference being significant (P less than 0.01). Referrals were very common in both settings, and when quality was assessed solely on the basis of the care actually given by the primary-care providers the difference between the two settings disappeared. Half the observed deficiencies in care related to failure to document the findings from history-taking and physical examination. From these and earlier findings we conclude that the emergency department can be an appropriate setting for the care of nontraumatic illness.     

The influence of density on frequency-dependent selection by wild birds feeding on artificial prey

Previous work has demonstrated frequency-dependent selection by wild garden birds when feeding on green and brown pastry ''baits''. When the density of baits is low, the common colour is eaten disproportionately more than the rare colour (apostatic selection), and when the density is very high, the rare colour is eaten disproportionately more than the common (anti-apostatic selection). We explored the relationship between frequency-dependent predation and density in an experiment at 16 separate sites, using four levels of density and two frequencies of green and brown. Analysis of estimates of log-relative risk ratios showed little evidence for frequency-independent selection, but frequency-dependent selection changed gradually from apostatic at low density to anti-apostatic at high density. The validity of these conclusions in terms of individual bird behaviour was confirmed by Monte-Carlo simulations. We thus conclude that selection by wild birds feeding on green and brown artificial prey is frequency dependent, and that the strength and direction of this selection changes with prey density in a gradual and predictable manner.     

Relevance of visual and olfactory cues for host location in the mustard leaf beetle Phaedon cochleariae

The relevance of visual and olfactory cues for host‐plant location is investigated in males and females of the oligophagous mustard leaf beetle Phaedon cochleariae Fabricius (Coleoptera: Chrysomelidae). Different objects are offered in a walking arena and the behaviour of beetles is observed. Beetles orient toward vertically or horizontally striped black and white pattern independent of stripe orientation. The results suggest that contrast facilitates orientation in the field, whereas the pattern itself may be less important for host location in dense vegetation. The response to green and yellow objects is tested to investigate discrimination abilities between young (green) and mature (yellow) leaves. Beetles prefer green over yellow independent of material (cardboard or leaves of Nasturtium officinale R. Br., Brassicaceae). Preference behaviour tested in a dual‐choice contact assay coincides with visual preferences, where adults prefer young, more nutritious leaves for feeding and oviposition. Furthermore, females discriminate between visual cues of green leaves and green cardboard, whereas males do not, indicating that females are more sensitive in colour discrimination. Differences in colour wavelength influence the choice of beetle behaviour more strongly than differences in intensity. Both sexes of P. cochleariae prefer volatiles of the host plant N. officinale, whereas only females respond to the main volatile compound 2‐phenylethyl isothiocyanate. Given a choice between visual and olfactory cues, males orientate towards the colour cues, whereas females do not show any preferences. In males, visual cues may thus override olfactory cues, whereas, in females, both are equally important, which may reflect different ecological requirements and/or physiological abilities.     

An investigation of colour discrimination with horses (Equus caballus)

The ability of four horses (Equus caballus) to discriminate coloured (three shades of blue, green, red, and yellow) from grey (neutral density) stimuli, produced by back projected lighting filters, was investigated in a two response forced-choice procedure. Pushes of the lever in front of a coloured screen were occasionally reinforced, pushes of the lever in front of a grey screen were never reinforced. Each colour shade was randomly paired with a grey that was brighter, one that was dimmer, and one that approximately matched the colour in terms of brightness. Each horse experienced the colours in a different order, a new colour was started after 85% correct responses over five consecutive sessions or if accuracy showed no trend over sessions. All horses reached the 85% correct with blue versus grey, three horses did so with both yellow and green versus grey. All were above chance with red versus grey but none reached criterion. Further analysis showed the wavelengths of the green stimuli used overlapped with the yellow. The results are consistent with histological and behavioural studies that suggest that horses are dichromatic. They differ from some earlier data in that they indicate horses can discriminate yellow and blue, but that they may have deficiencies in discriminating red and green.     

Pollen competition between morphs in a pollen‐color dimorphic herb and the loss of phenotypic polymorphism within populations

Flower color polymorphism is relatively uncommon in natural flowering plants, suggesting that maintenance of different color morphs within populations is difficult. To address the selective mechanisms shaping pollen‐color dimorphism, pollinator preferences and reproductive performance were studied over three years in Epimedium pubescens in which some populations had plants with either green or yellow pollen (and anthers). Visitation rate and pollen removal and receipt by the bee pollinator (Andrena emeishanica) did not differ between the two color morphs. Compared to the green morph, siring success of the yellow morph's pollen was lower, but that of mixtures of pollen from green and yellow morphs was lowest. This difference, corresponding to in vivo and ex vivo experiments on pollen performance, indicated that pollen germination, rather than tube growth, of the green morph was higher than that of the yellow morph and was seriously constrained in both morphs if a pollen competitor was present. A rare green morph may invade a yellow‐morph population, but the coexistence of pollen color variants is complicated by the reduced siring success of mixed pollinations. Potential pollen competition between morphs may have discouraged the maintenance of multiple phenotypes within populations, a cryptic mechanism of competitive exclusion.