Colour pattern modification by coldshock in Lepidoptera

Development ◽  
1984 ◽  
Vol 81 (1) ◽  
pp. 287-305
Author(s):  
H. Frederik Nijhout

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.

Development ◽  
1985 ◽  
Vol 86 (1) ◽  
pp. 191-203
Author(s):  
H. F. Nijhout

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.


2012 ◽  
Vol 279 (1749) ◽  
pp. 4907-4913 ◽  
Author(s):  
Richard M. Merrill ◽  
Richard W. R. Wallbank ◽  
Vanessa Bull ◽  
Patricio C. A. Salazar ◽  
James Mallet ◽  
...  

Adaptation to divergent ecological niches can result in speciation. Traits subject to disruptive selection that also contribute to non-random mating will facilitate speciation with gene flow. Such ‘magic’ or ‘multiple-effect’ traits may be widespread and important for generating biodiversity, but strong empirical evidence is still lacking. Although there is evidence that putative ecological traits are indeed involved in assortative mating, evidence that these same traits are under divergent selection is considerably weaker. Heliconius butterfly wing patterns are subject to positive frequency-dependent selection by predators, owing to aposematism and Müllerian mimicry, and divergent colour patterns are used by closely related species to recognize potential mates. The amenability of colour patterns to experimental manipulation, independent of other traits, presents an excellent opportunity to test their role during speciation. We conducted field experiments with artificial butterflies, designed to match natural butterflies with respect to avian vision. These were complemented with enclosure trials with live birds and real butterflies. Our experiments showed that hybrid colour-pattern phenotypes are attacked more frequently than parental forms. For the first time, we demonstrate disruptive ecological selection on a trait that also acts as a mating cue.


Development ◽  
1988 ◽  
Vol 102 (2) ◽  
pp. 377-385
Author(s):  
H.F. Nijhout ◽  
L.W. Grunert

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.


2019 ◽  
Author(s):  
Markus Moest ◽  
Steven M. Van Belleghem ◽  
Jennifer E. James ◽  
Camilo Salazar ◽  
Simon H. Martin ◽  
...  

AbstractNatural selection leaves distinct signatures in the genome that can reveal the targets and history of adaptive evolution. By analysing high-coverage genome sequence data from four major colour pattern loci sampled from nearly 600 individuals in 53 populations, we show pervasive selection on wing patterns across the Heliconius adaptive radiation. The strongest signatures correspond to loci with the greatest phenotypic effects, consistent with visual selection by predators, and are found in colour patterns with geographically restricted distributions. These recent sweeps are similar between co-mimics and indicate colour pattern turn-over events despite strong stabilizing selection. Using simulations we compare sweep signatures expected under classic hard sweeps with those resulting from adaptive introgression, an important aspect of mimicry evolution in Heliconius. Simulated recipient populations show a distinct ‘volcano’ pattern with peaks of increased genetic diversity around the selected target, consistent with patterns found in some populations. Our genomic data provide unprecedented insights into the recent history of selection across the Heliconius adaptive radiation.


2021 ◽  
Vol 288 (1946) ◽  
pp. 20203052
Author(s):  
Erika Páez ◽  
Janne K. Valkonen ◽  
Keith R. Willmott ◽  
Pável Matos-Maraví ◽  
Marianne Elias ◽  
...  

Most research on aposematism has focused on chemically defended prey, but the signalling difficulty of capture remains poorly explored. Similar to classical Batesian and Müllerian mimicry related to distastefulness, such ‘evasive aposematism' may also lead to convergence in warning colours, known as evasive mimicry. A prime candidate group for evasive mimicry areAdelphabutterflies, which are agile insects and show remarkable colour pattern convergence. We tested the ability of naive blue tits to learn to avoid and generalizeAdelphawing patterns associated with the difficulty of capture and compared their response to that of birds that learned to associate the same wing patterns with distastefulness. Birds learned to avoid all wing patterns tested and generalized their aversion to other prey to some extent, but learning was faster with evasive prey compared to distasteful prey. Our results on generalization agree with longstanding observations of striking convergence in wing colour patterns amongAdelphaspecies, since, in our experiments, perfect mimics of evasive and distasteful models were always protected during generalization and suffered the lowest attack rate. Moreover, generalization on evasive prey was broader compared to that on distasteful prey. Our results suggest that being hard to catch may deter predators at least as effectively as distastefulness. This study provides empirical evidence for evasive mimicry, a potentially widespread but poorly understood form of morphological convergence driven by predator selection.


2020 ◽  
Author(s):  
Erika Páez V ◽  
Janne K. Valkonen ◽  
Keith R. Willmott ◽  
Pável Matos-Maraví ◽  
Marianne Elias ◽  
...  

ABSTRACTMost research on aposematism has focused on chemically defended prey, but signalling difficulty of capture remains poorly explored. Similarly to classical Batesian and Müllerian mimicry related to distastefulness, such “evasive aposematism” may also lead to convergence in warning colours, known as evasive mimicry. A prime candidate group for evasive mimicry are Adelpha butterflies, which are agile insects and show remarkable colour pattern convergence. We tested the ability of naïve blue tits to learn to avoid and generalise Adelpha wing patterns associated with difficulty of capture, and compared their response to that of birds that learned to associate the same wing patterns with distastefulness. Birds learned to avoid all wing patterns tested, but learning was faster with evasive prey compared with distasteful prey. Birds generalised their learned avoidance from evasive models to imperfect mimics if the mimic shared colours with the model. Despite imperfect mimics gaining protection from bird’s generalisation, perfect mimics always had the best fitness, supporting selection for accurate mimicry. Faster avoidance learning and broader generalisation of evasive prey suggest that being hard to catch may deter predators at least as effectively as distastefulness. Our results provide empirical evidence for a potentially widespread alternative scenario, evasive mimicry, for the evolution of similar aposematic colour patterns.


Author(s):  
Danika L. Bannasch ◽  
Christopher B. Kaelin ◽  
Anna Letko ◽  
Robert Loechel ◽  
Petra Hug ◽  
...  

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.


Crustaceana ◽  
2019 ◽  
Vol 92 (7) ◽  
pp. 799-839 ◽  
Author(s):  
Akihiro Yoshikawa ◽  
Kazuho Ikeo ◽  
Junichi Imoto ◽  
Wachirah Jaingam ◽  
Lily Surayya Eka Putri ◽  
...  

Abstract Species of hermit crabs in the genus Clibanarius Dana, 1852 have adapted to various environments in the intertidal areas, including hard substrates and soft sediments. These species often bear a close morphological resemblance to each other, therefore, the colouration on the pereopods can be one of the reliable characteristics to distinguish the species. However, the evolutionary relationships among species with different colour patterns and relationships between colour patterns and habitat adaptation have not previously been investigated. Therefore, we reconstructed the phylogenetic relationships among 19 species of Clibanarius based on mitochondrial [12S rRNA, 16S rRNA and cytochrome oxidase I] and nuclear [histone H3] DNA markers. The results suggest that the striped and solid colour elements have evolved multiple times independently, with the ancestral colour pattern potentially being scattered, bright colour spots with a bright colour band. Our findings also suggest that evolutionary adaptation from hard substrates to mudflats and soft sediments may have occurred at least twice.


2021 ◽  
Vol 8 (6) ◽  
pp. 210308
Author(s):  
Collette Cook ◽  
Erin C. Powell ◽  
Kevin J. McGraw ◽  
Lisa A. Taylor

To avoid predation, many animals mimic behaviours and/or coloration of dangerous prey. Here we examine potential sex-specific mimicry in the jumping spider Habronattus pyrrithrix . Previous work proposed that males' conspicuous dorsal coloration paired with characteristic leg-waving (i.e. false antennation) imperfectly mimics hymenopteran insects (e.g. wasps and bees), affording protection to males during mate-searching and courtship. By contrast, less active females are cryptic and display less leg-waving. Here we test the hypothesis that sexually dimorphic dorsal colour patterns in H. pyrrithrix are most effective when paired with sex-specific behaviours. We manipulated spider dorsal coloration with makeup to model the opposite sex and exposed them to a larger salticid predator ( Phidippus californicus ). We predicted that males painted like females should suffer higher predation rates than sham-control males. Likewise, females painted like males should suffer higher predation rates than sham-control females. Contrary to expectations, spiders with male-like coloration were attacked more than those with female-like coloration, regardless of their actual sex. Moreover, males were more likely to be captured, and were captured sooner, than females (regardless of colour pattern). With these unexpected negative results, we discuss alternative functional hypotheses for H. pyrrithrix colours, as well as the evolution of defensive coloration generally.


2009 ◽  
Vol 91 (1) ◽  
pp. 39-46 ◽  
Author(s):  
R. M. SAWALHA ◽  
L. BELL ◽  
S. BROTHERSTONE ◽  
I. WHITE ◽  
A. J. WILSON ◽  
...  

SummarySusceptibility to scrapie is known to be associated with polymorphisms at the prion protein (PrP) gene, and this association is the basis of current selective programmes implemented to control scrapie in many countries. However, these programmes might have unintended consequences for other traits that might be associated withPrPgenotype. The objective of this study was to investigate the relationship betweenPrPgenotype and coat colour characteristics in two UK native sheep breeds valued for their distinctive coat colour patterns. Coat colour pattern, darkness and spotting andPrPgenotype records were available for 11 674 Badgerfaced Welsh Mountain and 2338 Shetland sheep. The data were analysed with a log–linear model using maximum likelihood. Results showed a strong significant association ofPrPgenotype with coat colour pattern in Badgerfaced Welsh Mountain and Shetland sheep and with the presence of white spotting in Shetland sheep. Animals with the ARR/ARR genotype (the most scrapie resistant) had higher odds of having a light dorsum and a dark abdomen than the reverse pattern. The implication of these associations is that selection to increase resistance to scrapie based only onPrPgenotype could result in change in morphological diversity and affect other associated traits such as fitness.


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