scholarly journals Visual signal evolution along complementary color axes in four bird lineages

Biology Open ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. bio052316
Author(s):  
Anand Krishnan ◽  
Avehi Singh ◽  
Krishnapriya Tamma
Keyword(s):  
Color Space ◽  
The Body ◽  
Color Variation ◽  
Visual Signals ◽  
Visual Signal ◽  
Chromatic Contrast ◽  
Present Evidence ◽  
Complementary Color ◽  
Line Passing ◽  
Species Specific

ABSTRACTAvian color patterns function in varied behavioral contexts, most being produced by only a handful of mechanisms including feather nanostructures and pigments. Within a clade, colors may not occupy the entire available space, and incorporating complementary colors may increase the contrast and efficacy of visual signals. Here, we describe plumage patterns in four ecologically and phylogenetically diverse bird families to test whether they possess complementary colors. We present evidence that plumage colors in each clade cluster along a line in tetrachromatic color space. Additionally, we present evidence that in three of these clades, this line contains colors on opposite sides of a line passing through the achromatic point (putatively complementary colors, presenting higher chromatic contrast). Finally, interspecific color variation over at least some regions of the body is not constrained by phylogenetic relatedness. By describing plumage patterns in four diverse lineages, we add to the growing body of literature suggesting that the diversity of bird visual signals is constrained. Further, we tentatively hypothesize that in at least some clades possessing bright colors, species-specific plumage patterns may evolve by swapping the distributions of a complementary color pair. Further research on other bird clades may help confirm whether these patterns are general across bird families.

scholarly journals Visual signal evolution along complementary color axes in four bird lineages

2019 ◽  
Author(s):  
Anand Krishnan ◽  
Avehi Singh ◽  
Krishnapriya Tamma
Keyword(s):  
Color Space ◽  
Dietary Factors ◽  
The Body ◽  
Color Variation ◽  
Visual Signals ◽  
Visual Signal ◽  
Relative Role ◽  
Chromatic Contrast ◽  
Present Evidence ◽  
Complementary Color

AbstractAnimal color patterns function in varied behavioral contexts including recognition, camouflage and even thermoregulation. The diversity of visual signals may be constrained by various factors, for example, dietary factors, and the composition of ambient environmental light (sensory drive). How have high-contrast and diverse signals evolved within these constraints? In four bird lineages, we present evidence that plumage colors cluster along a line in tetrachromatic color space. Additionally, we present evidence that this line represents complementary colors, which are defined as opposite sides of a line passing through the achromatic point (putatively for higher chromatic contrast). Finally, we present evidence that interspecific color variation over at least some regions of the body is not constrained by phylogenetic relatedness. Thus, we hypothesize that species-specific plumage patterns within these bird lineages evolve by swapping the distributions of a complementary color pair (or dark and light patches in one group, putatively representing an achromatic complementary axis). The relative role of chromatic and achromatic contrasts in discrimination may depend on the environment that each species inhabits.

scholarly journals How to colour a flower: on the optical principles of flower coloration

2016 ◽  
Vol 283 (1830) ◽  
pp. 20160429 ◽  
Author(s):  
Casper J. van der Kooi ◽  
J. Theo M. Elzenga ◽  
Marten Staal ◽  
Doekele G. Stavenga
Keyword(s):  
Optical Model ◽  
Systematic Approach ◽  
Species Differences ◽  
Flower Colour ◽  
Insect Vision ◽  
Visual Signals ◽  
Visual Signal ◽  
Selective Absorption ◽  
Chromatic Contrast ◽  
Selective Pressures

The coloration of flowers is due to the wavelength-selective absorption by pigments of light backscattered by structures inside the petals. We investigated the optical properties of flowers using (micro)spectrophotometry and anatomical methods. To assess the contribution of different structures to the overall visual signal of flowers, we used an optical model, where a petal is considered as a stack of differently pigmented and structured layers and we interpreted the visual signals of the model petals with insect vision models. We show that the reflectance depends, in addition to the pigmentation, on the petal's thickness and the inhomogeneity of its interior. We find large between-species differences in floral pigments, pigment concentration and localization, as well as floral interior structure. The fractions of reflected and transmitted light are remarkably similar between the studied species, suggesting common selective pressures of pollinator visual systems. Our optical model highlights that pigment localization crucially determines the efficiency of pigmentary filtering and thereby the chromatic contrast and saturation of the visual signal. The strongest visual signal occurs with deposition of pigments only on the side of viewing. Our systematic approach and optical modelling open new perspectives on the virtues of flower colour.

Androgen receptor modulates multimodal displays in the Bornean rock frog (Staurois parvus)

2021 ◽  
Author(s):  
Sarah M Smith ◽  
Amelia R Eigerman ◽  
Kerry M LeCure ◽  
Eseza Kironde ◽  
Auxenia Grace Privett-Mendoza ◽  
...  
Keyword(s):  
The Body ◽  
Visual Signals ◽  
Visual Signal ◽  
Dependent Manner ◽  
Adult Males ◽  
Physiological Basis ◽  
Temporal Properties ◽  
Signal Production ◽  
Vocal Signaling

Abstract Multimodal communication is common in the animal kingdom. It occurs when animals display by stimulating two or more receiver sensory systems, and often arises when selection favors multiple ways to send messages to conspecifics. Mechanisms of multimodal display behavior are poorly understood, particularly with respect to how animals coordinate the production of different signals. One important question is whether all components in a multimodal display share an underlying physiological basis, or whether different components are regulated independently. We investigated the influence of androgen receptors (AR) on the production of both visual and vocal signal components in the multimodal display repertoire of the Bornean rock frog (Staurois parvus). To assess the role of AR in signal production, we treated reproductively active adult males with the antiandrogen flutamide and measured the performance of each signal in the multimodal display. Our results show that blocking AR inhibited the production of multiple visual signals, including a conspicuous visual signal known as the “foot flag,” which is produced by rotating the hind limb above the body. However, flutamide treatment caused no measurable change in vocal signaling behavior, or in the frequency or fine temporal properties of males’ calls. Our study therefore suggests that activation of AR is not a physiological prerequisite to the coordination of multiple signals, in that it either does not regulate all signaling behaviors in a male’s display repertoire or it does so only in a context-dependent manner.

What's hot and what's not: defining torpor in free-ranging birds and mammals

2001 ◽  
Vol 79 (10) ◽  
pp. 1885-1890 ◽  
Author(s):  
Robert MR Barclay ◽  
Cori L Lausen ◽  
Lydia Hollis
Keyword(s):  
Body Temperature ◽  
The Body ◽  
Temperature Sensitive ◽  
The Past ◽  
Data Loggers ◽  
Temperature Thresholds ◽  
Radio Transmitters ◽  
Species Specific ◽  
Free Ranging ◽  
Lowered Body

With the development of small implantable data loggers and externally attached temperature-sensitive radio transmitters, increasing attention is being paid to determining the thermoregulatory strategies of free-ranging birds and mammals. One of the constraints of such studies is that without a direct measure of metabolic rate, it is difficult to determine the significance of lowered body temperatures. We surveyed the literature and found that many different definitions have been used to discriminate torpor from normothermy. Many studies use arbitrary temperature thresholds without regard for the normothermic body temperature of the individuals or species involved. This variation makes comparison among studies difficult and means that ecologically and energetically significant small reductions in body temperature may be overlooked. We suggest that normothermic body temperature for each individual animal should be determined and that torpor be defined as occurring when the body temperature drops below that level. When individuals' active temperatures are not available, a species-specific value should be used. Of greater value, however, are the depth and duration of torpor bouts. We suggest several advantages of this definition over those used in the past.

scholarly journals Possible mechanisms of anosognosia: a defect in self–awareness

1998 ◽  
Vol 353 (1377) ◽  
pp. 1903-1909 ◽  
Author(s):  
◽  
K. M. Heilman ◽  
A. M. Barrett ◽  
J. C. Adair
Keyword(s):  
Population Study ◽  
Sensory Feedback ◽  
Large Population ◽  
The Body ◽  
Spatial Neglect ◽  
Self Awareness ◽  
Knowledge Of Results ◽  
Present Evidence ◽  
Sensory Deficits ◽  
Parallel Processes

Anosognosia of hemiplegia is of interest for both pragmatic and theoretical reasons. We discuss several neuropsychological theories that have been proposed to explain this deficit. Although for psychological reasons people might deny deficits, the denial hypothesis cannot account for the hemispheric asymmetries associated with this disorder and cannot explain why some patients might deny one deficit and recognize another equally disabling deficit. There is some evidence that faulty feedback from sensory deficits, spatial neglect and asomatognosia might be responsible for anosognosia in some patients. However, these feedback hypotheses cannot account for anosognosia in all patients. Although the hemispheric disconnection hypothesis is appealing, disconnection is probably only a rare cause of this disorder. The feedforward intentional theory of anosognosia suggests that the discovery of weakness is dependent on attempted action and some patients might have anosognosia because they do not attempt to move. We present evidence that supports this theory. The presence of one mechanism of anosognosia, however, does not preclude the possibility that other mechanisms might also be working to produce this disorder. Although a large population study needs to be performed, we suspect that anosognosia might be caused by several of the mechanisms that we have discussed. On the basis of the studies of impaired corporeal self–awareness that we have reviewed, we can infer that normal self–awareness is dependent on several parallel processes. One must have sensory feedback and the ability to attend to both one's body and the space where parts of the body may be positioned or acting. One must develop a representation of the body, and this representation must be continuously modified by expectations (feedforward) and knowledge of results (feedback).

Number of Neoblasts in the Intact Body of Euplanaria torva and Dendrocoelum lacteum

Development ◽  
1961 ◽  
Vol 9 (1) ◽  
pp. 167-172
Author(s):  
Agnes Brøndsted ◽  
H. V. Brøndsted
Keyword(s):  
The Body ◽  
Regeneration Ability ◽  
Characteristic Variation ◽  
Species Specific ◽  
Regeneration Blastema

The regeneration, blastema in planarians is constituted by the totipotent neoblasts which migrate to the wound (Dubois, 1949). The rate of regeneration, measured by appearance of eyes in the blastema, shows a characteristic variation throughout the planarian body, thus constituting a static, time-graded regeneration field (Brøndsted, 1946). We do not know the mechanism underlying this species-specific feature. Neither do we know why some species, e.g. Dendrocoelum lacteum, are able to regenerate a head only from the part of the body lying anteriorly to the pharynx, whereas other species, e.g. Euplanaria torva, can regenerate a head from almost every part of the body. A possible explanation might be the number of available neoblasts. This idea was formulated by Curtis & Schulze (1934). They claim that in Procotyla fluviatilis, a species closely related to D. lacteum, the inability to regenerate a head from parts behind the pharynx is due to scarcity of neoblasts, as compared with species with greater regeneration ability.

scholarly journals Six-Month Color Stability Assessment of Two Calcium Silicate-Based Cements Used in Regenerative Endodontic Procedures

2019 ◽  
Vol 10 (1) ◽  
pp. 14 ◽  
Author(s):  
Paulo Palma ◽  
Joana Marques ◽  
Rui Falacho ◽  
Eder Correia ◽  
Alexandra Vinagre ◽  
...  
Keyword(s):  
Calcium Silicate ◽  
Saline Solution ◽  
Color Space ◽  
Mineral Trioxide Aggregate ◽  
Color Stability ◽  
Color Variation ◽  
Color Measurement ◽  
Suitable Alternative ◽  
Significance Level ◽  
Over Time

Aim: The purpose of the present study is to assess the color stability of two calcium silicate-based cements (CSCs) used in regenerative endodontic procedures (REPs). Methods: A total of 40 acrylic single-rooted transparent teeth, with immature apex, were used. Root canals were filled up to 3 mm below the level of the cementoenamel junction, with either saline solution (Mineral Trioxide Aggregate (MTA)/saline and Biodentine/saline) or blood (MTA/blood and Biodentine/blood). Subsequently, ProRoot MTA® or BiodentineTM was placed in the root canal to create a cervical barrier. Color measurement was carried out at four different evaluation periods (3 h, 72 h, 7 days, and 6 months). Shade analysis within the L* a* b* color space was performed and color variation (∆E) calculated. The significance level for statistical analysis was set at p < 0.05. Results: The four groups showed a significant decrease in L* values over time. The ΔE value increased over time for all groups but was not statistically significant for the Biodentine/blood group. Two-way ANOVA showed no interaction between the CSC and treatment (contact with saline solution or blood). CSC used was the factor responsible for ΔE over time, inducing statistically significant color variations from T3H to T7D (p = 0.04) and T3H to T6M (p < 0.01). After 6 months, MTA/saline had 5.08 (p = 0.001) higher ΔE than Biodentine/Saline and the MTA/blood had 3.65 (p = 0.009) higher than Biodentine/blood. Conclusions: After 6 months, regardless of blood exposure, Biodentine exhibits superior color stability compared to MTA. Biodentine might be a suitable alternative to MTA as a cervical barrier material in REPs.

Species-specific patterns of the use of burrows of Upogebia Leach, 1814 (Decapoda: Gebiidea: Upogebiidae) by the symbiotic alpheid shrimps Stenalpheops anacanthus Miya, 1997 and Athanas japonicus Kubo, 1936 (Decapoda: Caridea: Alpheidae) as revealed by laboratory quantification

2020 ◽  
Author(s):  
Yumi Henmi ◽  
Gyo Itani
Keyword(s):  
Evolutionary Biology ◽  
Evolutionary History ◽  
The Body ◽  
Symbiotic Relationship ◽  
Use Patterns ◽  
Species Specific ◽  
Burrow Use ◽  
First Time ◽  
The Relationship ◽  
Observation Period

Abstract Many alpheid shrimps live symbiotically on the body surface or inside the bodies of other invertebrates, while others use burrows made by other animals. The burrow symbiosis of alpheid shrimps is poorly studied in the context of ecology, probably because the cryptic infaunal nature of the relationship is hard to observe. The limited knowledge of the pattern of burrow use by alpheid shrimps leaves a gap in our understanding of their evolutionary history. We described and compared the behavior of Stenalpheops anacanthus  Miya, 1997 and Athanas japonicus  Kubo, 1936, two alpheid species living symbiotically in the burrows of the same host, Upogebia yokoyai  Makarov, 1938. We found that both alpheid species used U. yokoyai burrows in aquaria, but their burrow use patterns were quite different. The average time taken for S. anacanthus to enter the burrow for the first time was much shorter (1 min) than that of A. japonicus (13 min). Subsequently, S. anacanthus made longer use of the burrow (80% of the observation period) than A. japonicus (49%). The tail-first exit frequency, which may indicate a sudden expulsion from the burrow by the host, was more frequent in A. japonicus (25%) than in S. anacanthus (7%). Such differences could be attributed to the nature of the symbiotic relationship, obligate in S. anacanthus but facultative in A. japonicus. Because of the diversity of symbiotic lifestyles, there is considerable potential to study the ecology and evolutionary biology of burrow-symbiotic alpheids further.

scholarly journals Skin color variation: A study on Eastern and North East India

2019 ◽  
Vol 10 (3) ◽  
pp. 13-16
Author(s):  
Sumit Maitra ◽  
Diptendu Chatterjee ◽  
Arup Ratan Bandyopadhyay
Keyword(s):  
Ethnic Groups ◽  
Skin Color ◽  
Skin Pigmentation ◽  
Color Space ◽  
Color Variation ◽  
Phenotypic Traits ◽  
North East India ◽  
North East ◽  
Wide Range ◽  
Significant Difference

Background: Skin pigmentation is one of the most variable phenotypic traits and most noticeable of human polymorphisms. Skin pigmentation in humans is largely determined by the quantity and distribution of the pigment melanin. The literature review on skin color variation revealed a few works on skin pigmentation variation has been conducted in India from Southern, Western and Northern part. Aims and Objectives: To best of the knowledge, the present discourse is the first attempt to understand skin color variation from Eastern and North Eastern part of India among three populations. Materials and Methods: The present study consisted of 312 participants from Chakma and Tripuri groups of Tripura, North East India, and participants from Bengalee Hindu caste population from West Bengal. Skin color was measured by Konica Minolta CR-10 spectrophotometer which measures and quantifies the colors with a 3D color space (CIELAB) color space created by 3 axes. All the skin color measurements from each participant were taken from unexposed (underarm) left and right to get a mean and exposed (forehead) to sunlight. Results: The distribution of skin color variation among the three populations demonstrated significant (p<0.05) difference in lightness for unexposed and exposed indicating lightness in unexposed area. Furthermore, the present study revealed significant difference (p<0.05) in skin color among the ethnic groups across the body location and all three attributes (lightness, redness and yellowness). Conclusion: Generally, skin color variation may be elucidated by two main factors: individual differences in lightness and yellowness and by and large due to ethnicity, where diversity in redness is due to primarily due to different body locations. Variation in lightness have more characteristic probability. The present study first time reports the wide range of quantitative skin color variation among the three ethnic groups from Eastern and North East India and highest yellowness (b*) among the population from North East India.

The colouration and its behavioural significance in the corkwing wrasse, Crenilabrus melops

1974 ◽  
Vol 54 (4) ◽  
pp. 925-938 ◽  
Author(s):  
G. W. Potts
Keyword(s):  
Functional Significance ◽  
Mature Male ◽  
The Body ◽  
Visual Signals ◽  
Male Courtship ◽  
Male And Female ◽  
Vertical Bars ◽  
Mature Fish ◽  
Colour Patterns ◽  
Behavioural Significance

The colour patterns of the corkwing wrasse Crenilabrus melops and the functional significance of these patterns has been described. The resting colours of the fish are described for juveniles, mature males and mature females. These colour patterns assist in making the fish less conspicuous in their natural environment. Agonist behaviour is characterized by the development of a series of vertical bars on the body together with ritualized lateral and frontal displays in aggressive, and a head-up submissive posture in fright situations. Most aggressive behaviour is associated with the territorial activity of the mature male. Courtship and spawning activities involve a complex series of visual signals that synchronize the roles played by the male and female. The differences in colouration between juvenile and mature fish and the changes any individual can display have wrongly lead earlier authors to split C. melops into different species or varieties.

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