scholarly journals Eyespot colour pattern determination by serial induction in fish: Mechanistic convergence with butterfly eyespots

2012 ◽  
Vol 2 (1) ◽  
Author(s):  
Yoshikazu Ohno ◽  
Joji M. Otaki
Keyword(s):  
Colour Pattern ◽  
Pattern Determination

Cautery-induced colour patterns in Precis coenia (Lepidoptera: Nymphalidae)

Development ◽  
1985 ◽  
Vol 86 (1) ◽  
pp. 191-203
Author(s):  
H. F. Nijhout
Keyword(s):  
Computer Simulations ◽  
Hind Wing ◽  
Wing Surface ◽  
Colour Pattern ◽  
Physiological Conditions ◽  
Classical Work ◽  
Pattern Determination ◽  
Colour Patterns ◽  
Experimental Findings ◽  
Precis Coenia

Cautery of the dorsal hind wing in the butterfly, Precis coenia, induces the formation of a concentric colour pattern around the site of injury. The induced pattern is identical in pigmentation to the eyespots that normally develop on this wing surface. This response to cautery also occurs, though much less dramatically, on the ventral forewing. In addition to the peculiar response to cautery, the dorsal hindwing of Precis also develops a series of unique pattern aberrations in response to coldshock. These consist of irregular elongation of the anterior eyespot along the proximodistal axis of the wing. In the most dramatic aberrations the eyespot field covers the entire anterior half of the wing surface. An analysis is presented that attempts to reconcile the effects of cautery on the Precis hindwing with the very different morphological effects of cautery on the colour pattern of Ephestia kühniella, described by Kühn & Von Engelhardt. Computer simulations reveal that the finding presented in this paper, as well as the classical work on Ephestia, can both be explained by assuming that the site of cautery becomes a sink for one of the morphogens involved in colour pattern determination. The experimental findings furthermore indicate that minor perturbations of the wing epidermis can evoke the physiological conditions that attend normal eyespot determination. It is shown that this interpretation also helps to explain the unusual pattern modifications following coldshock.

scholarly journals Colour pattern regulation after surgery on the wing disks of Precis coenia (Lepidoptera: Nymphalidae)

Development ◽  
1988 ◽  
Vol 102 (2) ◽  
pp. 377-385
Author(s):  
H.F. Nijhout ◽  
L.W. Grunert
Keyword(s):  
Colour Pattern ◽  
Central Field ◽  
Wing Margin ◽  
Cut Edge ◽  
Wing Disk ◽  
Developmental Disturbances ◽  
Pattern Determination ◽  
Precis Coenia ◽  
Pattern Regulation

Partial ablations were done in situ on the imaginal disks of the hindwing in larvae of Precis coenia at ages between 2 and 9 days prior to pupation. While there was no regeneration of the wing lamina, the cut edge developed normal marginal scales and a marginal colour pattern if the ablation was done more than 3–5 days prior to pupation. The response of elements of the marginal colour pattern to partial ablation of the wing disk indicates that the wing margin has an important role in colour pattern determination and appears to act as a sink for a pattern-inducing signal. While the elements of the marginal colour pattern regulate to the shape and position of the new wing margin, the eyespots changed their shape and size but not their position upon partial ablation of the wing disk. When a cut was positioned near one of the dorsal eyespots, the outer rings of the eyespot opened up so that its central field became contiguous with the new margin. The behaviour of the dorsal eyespots of the hindwing in response to ablation of the wing disk, as well as to other developmental disturbances, appears to be the reverse of those on the forewing and ventral hindwing. We conclude that the central field of a dorsal eyespot and the wing margin share similar controlling properties with respect to pattern, and that both appear to act as sinks or as the inverse of the sources of pattern-inducing signal found in the eyespots of the forewing.

Colour pattern modification by coldshock in Lepidoptera

Development ◽  
1984 ◽  
Vol 81 (1) ◽  
pp. 287-305
Author(s):  
H. Frederik Nijhout
Keyword(s):  
Colour Pattern ◽  
Gradient System ◽  
Experimental Animals ◽  
Vanessa Cardui ◽  
Adult Wing ◽  
Wing Patterns ◽  
Pattern Determination ◽  
Colour Patterns ◽  
Precis Coenia ◽  
Morphological Series

When young pupae of Vanessa cardui, V. virginiensis and Precis coenia (Lepidoptera: Nymphalidae) are exposed to severe coldshock many develop aberrant adult wing patterns. For each species, a synchronous cohort of experimental animals always develops a broad range of aberrant pattern morphologies but these can always be arranged in a single unbranched morphological series. When such phenotypic series are compared, between species and between wing surfaces within a species (each wing surface usually bears a different colour pattern), many parallel modifications and trends become evident. These parallelisms reveal certain homologies of pattern elements and suggest that a common physiology underlies the development of a considerable diversity of normal and aberrant colour patterns. The case is made that the phenotypic series produced may represent either a series of sequential stages in colour pattern determination or, a series of quantitatively different ‘interpretations’ of an established gradient system. Colour pattern morphoclines reveal which patterns are developmentally ‘adjacent’ to one another and may therefore prove useful in elucidating the evolution of patterns.

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.

Morphology and diet of two sympatric colubrid snakes, Chironius flavolineatus and Chironius quadricarinatus (Serpentes: Colubridae)

2008 ◽  
Vol 29 (2) ◽  
pp. 149-160 ◽  
Author(s):  
Otavio Augusto Vuolo Marques ◽  
Ronaldo Fernandes ◽  
Roberta Richard Pinto
Keyword(s):  
Foraging Behaviour ◽  
Sexual Size Dimorphism ◽  
Sympatric Species ◽  
Colour Pattern ◽  
Ontogenetic Variation ◽  
Brazilian Cerrado ◽  
Size Dimorphism ◽  
Snake Species ◽  
Dietary Ecology ◽  
Arboreal Habit

Abstract The morphometry and diet of two sympatric species of Chironius (C. flavolineatus and C. quadricarinatus) from Brazilian Cerrado are described. The two snake species differ in external morphology, as Chironius flavolineatus was the largest species (body, tail and eyes) whereas C. quadricarinatus the heaviest. Each species also showed marked sexual size dimorphism. In terms of dietary ecology, both species feed exclusively on frogs with a heavy preference for hylids and may have tendency to eat small items, as noticed in other colubrine species. These two snake species showed a brownish colour pattern and exhibited no ontogenetic variation, suggesting that juveniles and adults use similar substrates. Chironius flavolineatus and C. quadricarinatus present a semi-arboreal habit, with active foraging behaviour, feeding in the ground most of time. Chironius flavolineatus uses higher vegetation for resting and, based on morphological results, seems to be more arboreal than C. quadricarinatus.

scholarly journals Spots and stripes: ecology and colour pattern evolution in butterflyfishes

2013 ◽  
Vol 280 (1757) ◽  
pp. 20122730 ◽  
Author(s):  
Jennifer L. Kelley ◽  
John L. Fitzpatrick ◽  
Sami Merilaita
Keyword(s):  
Colour Pattern

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.

A new species of smooth-skinned Spinomantis frog (Anura: Mantellidae) from south-eastern Madagascar

Zootaxa ◽  
2017 ◽  
Vol 4317 (2) ◽  
pp. 379
Author(s):  
MIGUEL VENCES ◽  
JÖRN KÖHLER ◽  
FRANK GLAW
Keyword(s):  
National Park ◽  
Type Specimen ◽  
High Elevation ◽  
Type Locality ◽  
Colour Pattern ◽  
Molecular Evidence ◽  
Rrna Gene ◽  
Reciprocal Monophyly ◽  
South Eastern ◽  
Candidate Species

We present molecular evidence for the presence of two species morphologically similar to Spinomantis bertini in Andohahela National Park, south-eastern Madagascar, differing by 5.5−6.3% pairwise DNA sequence divergences in the mitochondrial 16S rRNA gene. One of these was observed at higher elevations of ca. 1650 m above sea level, whereas the other was found at lower elevations of ca. 715 m a.s.l., close to the type locality of S. bertini (Isaka-Ivondro), and in one other location (Andreoky, ca. 1050 a.s.l.). We herein assign these low- to mid-elevation specimens to S. bertini based on their occurrence near the type locality and general agreement in colour pattern with the type specimen of Gephyromantis bertini Guibé, 1947. The high-elevation form is described as Spinomantis beckei sp. nov. based on its molecular divergence and reciprocal monophyly with respect to S. bertini, lower expression of greenish dorsal colour and less distinct frenal stripe. Based on a comparison of published call descriptions for S. bertini and our recordings of S. beckei, we hypothesize that S. bertini has a lower note repetition rate in advertisement calls. Molecular data suggest that the S. bertini species complex is more diverse than previously recognized, with at least two more candidate species identified: S. sp. Ca7 from Ranomafana National Park, and a newly identified candidate species S. sp. Ca12 from Pic d’Ivohibe Special Reserve. 

A possible function of the caudal spot in characid fishes

1977 ◽  
Vol 55 (7) ◽  
pp. 1063-1066 ◽  
Author(s):  
J. D. McPhail
Keyword(s):  
The Body ◽  
Colour Pattern ◽  
Selective Basis ◽  
The Difference

The suggestion that caudal pigment spots in fishes can act as deflection marks is tested experimentally. Fish with artificial caudal spots escape predators more often than the same species without spots, but the difference was not significant (0.1 < p < 0.2). However in fish captured, the place on the body where the fish was seized was shifted posteriorly by the presence of a spot (p < 0.01). Although the results are equivocal, they do suggest a possible selective basis for convergence in colour pattern in small characid fishes.

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