scholarly journals III. Studies in colour changes of fish. - Part II. —An analysis of the colour patterns of the dab. - Part III. —The action of nicotin and adrenalin in the dab. - Part IV. —The action of caffeine in the dab, and a theory of the control of colour changes in fish

1927 ◽  
Vol 215 (421-430) ◽  
pp. 177-200 ◽  
Keyword(s):  
The Body ◽  
Colour Pattern ◽  
Complete Analysis ◽  
Morphological Variations ◽  
Differential Reaction ◽  
Flat Fish ◽  
Colour Changes ◽  
Morphological Differences ◽  
Colour Patterns ◽  
The Many

In the course of investigations on the action of certain drugs on the colour of the dab, it became increasingly evident that not only should a microscopic examination be made of the results, but that apart from a complete analysis of the colour pattern of the fish, such an examination would be unintelligible. I am not aware that any such analysis has been made of so complicated a colour scheme. Abolin (see List of Papers, p. 198) has analysed the colour pattern of the minnow, and in a previous paper I have pointed out that the barring on the minnow is partly due to physiological differences and partly to morphological variations. Sumner has also given a description of the patterns on certain flat-fish, but his observations were purely macroscopic. The main problem which has presented itself in this field is this :—Do all the chromatophores on the skin expand and contract synchronously and to the same degree? In other words: Are the various colour phases and manifestations of markings due to morphological differences alone? Sumner, as the result of researches carried out on flat-fish, has come to the conclusion that the many variations of colour, pattern and shade cannot be altogether explained by the assumption of a synchronous reaction of all the chromatophores, and that there must be some differential reaction of the chromatophores situated on the markings. Hogben is opposed to this view and thinks that, as “the extent of melanophore expansion in response to the intensity of a uniform background displays a very subtle gradation, it is not unlikely that the effect of a variegated background is simply to reproduce throughout the body a state of melanophore response, which renders more or less apparent a pattern dependent wholly on the numerical distribution of the melanophores in different areas.” In the present research this problem has been approached by a study of the reactions of the dab to uniform backgrounds, to ascertain the extent of the “subtle gradation” and to supply the necessary data for the further discussion of this problem.

scholarly journals Locomotor mimicry in Heliconius butterflies: contrast analyses of flight morphology and kinematics

1999 ◽  
Vol 354 (1380) ◽  
pp. 203-214 ◽  
Author(s):  
Robert B. Srygley
Keyword(s):  
Wing Length ◽  
Beat Frequency ◽  
Warning Signal ◽  
Wing Shape ◽  
The Body ◽  
Colour Pattern ◽  
Müllerian Mimicry ◽  
Flight Morphology ◽  
Mullerian Mimicry ◽  
Colour Patterns

Müllerian mimicry is a mutualism involving the evolutionary convergence of colour patterns of prey on a warning signal to predators. Behavioural mimicry presumably adds complexity to the signal and makes it more difficult for Batesian mimics to parasitize it. To date, no one has quantified behavioural mimicry in Müllerian mimicry groups. However, morphological similarities among members of mimicry groups suggested that pitching oscillations of the body and wing–beat frequency (WBF) might converge with colour pattern. I compared the morphology and kinematics of four Heliconius species, which comprised two mimicry pairs. Because the mimics arose from two distinct lineages, the relative contributions of mimicry and phylogeny to variation in the species' morphologies and kinematics were examined. The positions of the centre of body mass and centre of wing mass and wing shape diverged among species within lineages, and converged among species within mimicry groups. WBF converged within mimicry groups, and it was coupled with body pitching frequency. However, body–pitching frequency was too variable to distinguish mimicry groups. Convergence in WBF may be due, at least in part, to biomechanical consequences of similarities in wing length, wing shape or the centre of wing mass among co–mimics. Nevertheless, convergence in WBF among passion–vine butterflies serves as the first evidence of behavioural mimicry in a mutualistic context.

Ontogenetic changes in the ventral colouration of post metamorphic Elachistocleis haroi Pereyra, Akmentins, Laufer, Vaira, 2013 (Anura: Microhylidae)

2020 ◽  
Vol 41 (2) ◽  
pp. 191-200
Author(s):  
Diego Bueno-Villafañe ◽  
Andrea Caballlero-Gini ◽  
Marcela Ferreira ◽  
Flavia Netto ◽  
Danilo Fernández Ríos ◽  
...  
Keyword(s):  
Colour Change ◽  
Colour Pattern ◽  
Ecological Significance ◽  
Ontogenetic Changes ◽  
Stages Of Development ◽  
Reversible Process ◽  
Yellow Colour ◽  
Sexual Display ◽  
Colour Patterns ◽  
The Many

Abstract Ontogenetic colour change (OCC) is defined as the progressive and non-reversible process of changes in colouration of organisms associated with their development. Among the many vertebrate groups, amphibians are particularly impressive for their strikingly wide variety of colours, colour patterns, and signals, whose evolutionary and ecological significance have been poorly studied. Elachistocleis comprises 18 species currently separated into two main groups based on their ventral colour pattern: one immaculate and the other with specks and/or colour patches. Elachistocleis haroi is a small-sized species within the immaculate venter group, distributed in the Yungas and Dry Chaco ecoregions from which little information is known. In a comprehensive sampling of post-metamorphic individuals of E. haroi at different stages of development we identified a significant variation in ventral colour pattern, which could denote a progressive filling of yellow colour according to an ontogenetic pattern. To test this hypothesis, we analysed 39 post-metamorphic individuals of E. haroi at different stages of development with imaging procedures. We found that yellow spots and their intensity are significantly related to snout-vent length, as major expansion of colour on the sides, gular region and male chest, as almost no development on the belly. We briefly discuss our findings in relation to sexual display and predation avoidance. To our knowledge, this is the first analysis of post-metamorphic OCC in ventral colouration in the genus Elachistocleis.

Observations on Phases of the Red-Winged Locust in Northern Rhodesia

1934 ◽  
Vol 25 (1) ◽  
pp. 101-128 ◽  
Author(s):  
A. P. G. Michelmore ◽  
W. Allan
Keyword(s):  
Young Adults ◽  
Young Adult ◽  
Relative Size ◽  
The Body ◽  
Colour Pattern ◽  
Brown Pigment ◽  
Red Pigment ◽  
Colour Changes ◽  
Purple Coloration ◽  
Dark Coloration

Summary1. The egg, vermiform larva, and the nymphal stages of ph. gregaria are described. It is shown that six stages occur, or seven instars including the vermiform larva. These stages can be distinguished by (a) the number of antennal joints, (b) the degree of backward prolongation of the pronotum, (c) the differentiation of the terminal abdominal structures. Measurements of the pronotum and femur served to distinguish the stages in material from the same swarm, but the absolute measurements cannot be used to distinguish material from different sources.2. The colour pattern of ph. dissocians is analysed, and colour changes are indicated as divergences from the gregaria pattern. Forms of ph. dissocians observed in the field are grouped into several types the relationships of which are illustrated, and the environmental factors which produce them are discussed.3. Hoppers believed to be of ph. congregans could not be distinguished from certain forms of ph. dissocians.4. Cage experiments in which hoppers were reared under varying degrees of crowding are described. It is strongly indicated that activity which is induced by crowding influences the development of gregaria colouring. The green colouring of dissocians hoppers appears to be associated with high humidity conditions and the presence of green food. Other colours of dissocians hoppers are conditioned by those of the environment.5. An aberrant pallid type of hopper is described and its origin is ascribed to the effects of parasitism by Nematodes and possibly also by Dipterous larvae.6. Certain inferences regarding the processes in the formation of the colour pattern are inferred from a consideration of the effects of parasitism and of dissocians producing factors.7. The colourings of young adults of ph. gregaria a few days after the ultimate moult and of types taken from large swarms in August are described. It is shown that colour changes occur gradually in the field, the conspicuous pattern of light and dark coloration of the young adult being obscured and finally hidden by the development of a bright red pigmentation.8. The colouring of young adults of ph. dissocians is described. These show a pattern of light and dark coloration similar to that of the young adult of ph. gregaria, from which it is indistinguishable, immediately after the ultimate moult. In ph. transiens no marked colour change takes place throughout the life of the individual except the development of a purple coloration on the hind wings.9. Factors influencing adult colouring are discussed. Adults crowded in cages and derived from hoppers reared under crowded conditions did not undergo the colour changes observed in the field. Material taken from large swarms in the field and showing some development of swarm colouring were maintained under crowded and uncrowded conditions. The red pigment of the body changed to a dark brown in both cases. Under uncrowded conditions no further change took place except a conspicuous development of purple coloration on the hind wings in all individuals. Under crowded conditions the brown pigment spread, its final distribution resembling that of the red pigment in later swarm types from the field, but the red colouring of the hind wings was developed only to a very slight extent in a few individuals. In the case of individuals isolated completely the swarm colouring was lost entirely.10. It is inferred that swarm colouring in the adult is associated with crowding and possibly with activity and that development of the red and purple coloration on the hind wings in gregaria and transiens is affected by different factors and possibly differs in composition.11. Biometrical data obtained from a variety of types is tabulated and discussed. Material varied from types taken from very large and dense swarms to what might be described as “solitaria beginning to congregate.”12. It is shown that certain measurable characters, especially the relative size of the sexes, the degree of development of the femur in relation to the wing, and the relative length and degree of constriction of the pronotum differ greatly in gregaria and transiens types and may be used to distinguish them.13. In the case of material from very large and dense swarms and from very small loose swarms no differences in the characters on which the types could readily be distinguished were observed. It may be that these small groups were derived from larger swarms.14. Interesting aberrations occur in the case of a swarm believed to have been one of the earliest to migrate any considerable distance after the commencement of swarming. The quantity of material was insufficient to permit of very reliable comparison but it would appear that in these forms the pronotum of the female was generally not shortened or constricted to the same extent as in extreme gregaria, although the construction of the pronotum of the male approximated fairly closely to that of more extreme gregaria

scholarly journals HIGH-RESOLUTION CHARACTERIZATION OF MALE ORNAMENTATION AND REEVALUATION OF SEX LINKAGE IN GUPPIES

2020 ◽  
Author(s):  
Jake Morris ◽  
Iulia Darolti ◽  
Wouter van der Bijl ◽  
Judith E. Mank
Keyword(s):  
High Resolution ◽  
Natural Populations ◽  
Colour Pattern ◽  
Sexually Dimorphic ◽  
Animal Colouration ◽  
In The Wild ◽  
Colour Changes ◽  
Colour Patterns ◽  
Male Ornaments

AbstractColouration plays a key role in the ecology of many species, influencing how an organism interacts with its environment, other species and conspecifics. Guppies are sexually dimorphic, with males displaying sexually selected colouration resulting from female preference. Previous work has suggested that much of guppy colour pattern variation is Y-linked. However, it remains unclear how many individual colour patterns are Y-linked in natural populations as much of the previous work has focused on phenotypes either not found in the wild, or aggregate measures such as total colour area. Moreover, ornaments have traditionally been identified and delineated by hand, and computational methods now make it possible to extract pixels and identify ornaments more automatedly, reducing the potential for human bias. Here we developed a pipeline for automated ornament identification and high-resolution image analysis of male guppy colour patterns and applied it to a multigenerational pedigree. Our results show that loci controlling the presence or absence of individual male ornaments in our population are not predominantly Y-linked. However, we find that ornaments of similar colour are not independent of each other, and modifier loci that affect whole animal colouration appear to be at least partially Y-linked. Considering these results, Y-linkage of individual ornaments may not be important in driving colour changes in natural populations of guppies, or in expansions of the non-recombining Y region, while Y-linked modifier loci that affect aggregate traits may well play an important role.

scholarly journals High-resolution characterization of male ornamentation and re-evaluation of sex linkage in guppies

2020 ◽  
Vol 287 (1937) ◽  
pp. 20201677
Author(s):  
Jake Morris ◽  
Iulia Darolti ◽  
Wouter van der Bijl ◽  
Judith E. Mank
Keyword(s):  
High Resolution ◽  
Natural Populations ◽  
Colour Pattern ◽  
Sexually Dimorphic ◽  
In The Wild ◽  
Colour Changes ◽  
Colour Patterns ◽  
Male Ornaments ◽  
Automated Methods

Coloration plays a key role in the ecology of many species, influencing how an organism interacts with its environment, other species and conspecifics. Guppies are sexually dimorphic, with males displaying sexually selected coloration resulting from female preference. Previous work has suggested that much of guppy colour pattern variation is Y-linked. However, it remains unclear how many individual colour patterns are Y-linked in natural populations as much of the previous work has focused on phenotypes either not found in the wild, or aggregate measures such as total colour area. Moreover, ornaments have traditionally been identified and delineated by hand, and computational methods now make it possible to extract pixels and identify ornaments with automated methods, reducing the potential for human bias. Here we developed a pipeline for semi-automated ornament identification and high-resolution image analysis of male guppy colour patterns and applied it to a multigenerational pedigree. Our results show that loci controlling the presence or the absence of individual male ornaments in our population are not predominantly Y-linked. However, we find that ornaments of similar colour are not independent of each other, and modifier loci that affect whole animal coloration appear to be at least partially Y-linked. Considering these results, Y-linkage of individual ornaments may not be important in driving colour changes in natural populations of guppies, or in expansions of the non-recombining Y region, while Y-linked modifier loci that affect aggregate traits may well play an important role.

Representing utility and deploying the body

2020 ◽  
Vol 43 ◽  
Author(s):  
David Spurrett
Keyword(s):  
Functional Activity ◽  
Degrees Of Freedom ◽  
The Body ◽  
Target Article ◽  
Processing Demands ◽  
The Many

Abstract Comprehensive accounts of resource-rational attempts to maximise utility shouldn't ignore the demands of constructing utility representations. This can be onerous when, as in humans, there are many rewarding modalities. Another thing best not ignored is the processing demands of making functional activity out of the many degrees of freedom of a body. The target article is almost silent on both.

Gender determination of caucasoid hair using image analysis

1993 ◽  
Vol 51 ◽  
pp. 216-217
Author(s):  
T.B. Ball ◽  
W.M. Hess
Keyword(s):  
Image Analysis ◽  
Cross Sections ◽  
Scalp Hair ◽  
The Body ◽  
Equivalent Diameter ◽  
Cross Sectional ◽  
Hair Samples ◽  
Length Width ◽  
Morphological Differences

It has been demonstrated that cross sections of bundles of hair can be effectively studied using image analysis. These studies can help to elucidate morphological differences of hair from one region of the body to another. The purpose of the present investigation was to use image analysis to determine whether morphological differences could be demonstrated between male and female human Caucasian terminal scalp hair.Hair samples were taken from the back of the head from 18 caucasoid males and 13 caucasoid females (Figs. 1-2). Bundles of 50 hairs were processed for cross-sectional examination and then analyzed using Prism Image Analysis software on a Macintosh llci computer. Twenty morphological parameters of size and shape were evaluated for each hair cross-section. The size parameters evaluated were area, convex area, perimeter, convex perimeter, length, breadth, fiber length, width, equivalent diameter, and inscribed radius. The shape parameters considered were formfactor, roundness, convexity, solidity, compactness, aspect ratio, elongation, curl, and fractal dimension.

scholarly journals From Abbott Thayer to the present day: what have we learned about the function of countershading?

2008 ◽  
Vol 364 (1516) ◽  
pp. 519-527 ◽  
Author(s):  
Hannah M Rowland
Keyword(s):  
Empirical Work ◽  
Quantitative Measure ◽  
Convincing Evidence ◽  
Colour Pattern ◽  
Protective Effects ◽  
Empirical Testing ◽  
Background Matching ◽  
Visual Characteristics ◽  
Subjective Evidence ◽  
The Many

Of the many visual characteristics of animals, countershading (darker pigmentation on those surfaces exposed to the most lighting) is one of the most common, and paradoxically one of the least well understood. Countershading has been hypothesized to reduce the detectability of prey to visually hunting predators, and while the function of a countershaded colour pattern was proposed over 100 years ago, the field has progressed slowly; convincing evidence for the protective effects of countershading has only recently emerged. Several mechanisms have been invoked for the concealing function of countershading and are discussed in this review, but the actual mechanisms by which countershading functions to reduce attacks by predators lack firm empirical testing. While there is some subjective evidence that countershaded animals match the background on which they rest, no quantitative measure of background matching has been published for countershaded animals; I now present the first such results. Most studies also fail to consider plausible alternative explanations for the colour pattern, such as protection from UV or abrasion, and thermoregulation. This paper examines the evidence to support each of these possible explanations for countershading and discusses the need for future empirical work.

scholarly journals Dog colour patterns explained by modular promoters of ancient canid origin

2021 ◽  
Author(s):  
Danika L. Bannasch ◽  
Christopher B. Kaelin ◽  
Anna Letko ◽  
Robert Loechel ◽  
Petra Hug ◽  
...  
Keyword(s):  
Colour Pattern ◽  
Hair Cycle ◽  
Temporal And Spatial Distribution ◽  
Multiple Alleles ◽  
Haplotype Combination ◽  
Regulatory Modules ◽  
Regulatory Module ◽  
Temporal And Spatial ◽  
Selection For ◽  
Colour Patterns

AbstractDistinctive colour patterns in dogs are an integral component of canine diversity. Colour pattern differences are thought to have arisen from mutation and artificial selection during and after domestication from wolves but important gaps remain in understanding how these patterns evolved and are genetically controlled. In other mammals, variation at the ASIP gene controls both the temporal and spatial distribution of yellow and black pigments. Here, we identify independent regulatory modules for ventral and hair cycle ASIP expression, and we characterize their action and evolutionary origin. Structural variants define multiple alleles for each regulatory module and are combined in different ways to explain five distinctive dog colour patterns. Phylogenetic analysis reveals that the haplotype combination for one of these patterns is shared with Arctic white wolves and that its hair cycle-specific module probably originated from an extinct canid that diverged from grey wolves more than 2 million years ago. Natural selection for a lighter coat during the Pleistocene provided the genetic framework for widespread colour variation in dogs and wolves.

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