scholarly journals Uncovering the effects of Müllerian mimicry on the evolution of conspicuousness in colour patterns

2019 ◽  
Author(s):  
Ombeline Sculfort ◽  
Ludovic Maisonneuve ◽  
Marianne Elias ◽  
Thomas G. Aubier ◽  
Violaine Llaurens
Keyword(s):  
Predation Risk ◽  
Prey Species ◽  
Colour Pattern ◽  
Warning Coloration ◽  
Local Composition ◽  
Müllerian Mimicry ◽  
In The Wild ◽  
Mullerian Mimicry ◽  
Colour Patterns ◽  
Number Of Individuals

AbstractThe conspicuousness of colour pattern in defended species associates with a high detectability by predators, making its evolution puzzling. Müllerian mimicry, the convergence of warning coloration among defended prey species, is pervasive in communities of conspicuous prey, and mimicry switches, with mutant individuals having the same colour pattern as other co-mimetic species, may often associate with changes in conspicuousness. Yet, the implication of mimicry for the evolution of conspicuousness has not been considered. Here, we build a model describing the population dynamics of conspicuous defended prey to explore the invasion conditions of mutants that differ from other individuals by their conspicuousness. We assume that predation risk depends not only on the number of individuals sharing a given colour pattern within the population but also on the presence of co-mimetic species. We compare the evolutionary fates of mutant colour patterns (1) that are similar to the ancestral colour pattern and thus belong to the same mimicry ring (assemblage of co-mimetic species), or (2) that are different from the ancestral colour pattern and thus potentially belong to a distinct mimicry ring. Our analytical derivations show that (1) less conspicuous colour patterns are more likely to be selected within mimicry ring, and that (2) a mimicry switch lowering predation risk can promote the invasion of a more conspicuous colour pattern. We thus highlight that the variation in conspicuousness observed in the wild results not only from the characteristics of the colour pattern (detectability, salience) but also from the local composition of mimetic communities.

scholarly journals Risk of social colours in an agamid lizard: implications for the evolution of dynamic signals

2019 ◽  
Vol 15 (5) ◽  
pp. 20190207 ◽  
Author(s):  
Madhura S. Amdekar ◽  
Maria Thaker
Keyword(s):  
Natural Selection ◽  
Social Interactions ◽  
Predation Risk ◽  
Colour Pattern ◽  
Male Aggression ◽  
Visual Systems ◽  
In The Wild ◽  
Predation Costs ◽  
Colour Patterns ◽  
Ecological Cost

The forces of sexual and natural selection are typically invoked to explain variation in colour patterns of animals. Although the benefits of conspicuous colours for social signalling are well documented, evidence for their ecological cost, especially for dynamic colours, remains limited. We examined the riskiness of colour patterns of Psammophilus dorsalis , a species in which males express distinct colour combinations during social interactions. We first measured the conspicuousness of these colour patterns on different substrates based on the visual systems of conspecifics and predators (bird, snake, canid) and then quantified actual predation risk on these patterns using wax/polymer lizard models in the wild. The black and red male state exhibited during courtship was the most conspicuous to all visual systems, while the yellow and orange male aggression state and the brown female colour were least conspicuous. Models bearing the courtship colour pattern experienced the highest predator attacks, irrespective of the substrate they were placed on. Thus, social colours of males are not only conspicuous but also risky. Using physiological colours to shift in and out of conspicuous states may be an effective evolutionary solution to balance social signalling benefits with predation costs.

scholarly journals Unsupervised machine learning reveals mimicry complexes in bumblebees occur along a perceptual continuum

2019 ◽  
Vol 286 (1910) ◽  
pp. 20191501 ◽  
Author(s):  
Briana D. Ezray ◽  
Drew C. Wham ◽  
Carrie E. Hill ◽  
Heather M. Hines
Keyword(s):  
Machine Learning ◽  
Large Scale ◽  
Colour Pattern ◽  
Unsupervised Machine Learning ◽  
Transition Zones ◽  
Müllerian Mimicry ◽  
Active Selection ◽  
Mullerian Mimicry ◽  
Colour Patterns ◽  
Patterns And Processes

Müllerian mimicry theory states that frequency-dependent selection should favour geographical convergence of harmful species onto a shared colour pattern. As such, mimetic patterns are commonly circumscribed into discrete mimicry complexes, each containing a predominant phenotype. Outside a few examples in butterflies, the location of transition zones between mimicry complexes and the factors driving mimicry zones has rarely been examined. To infer the patterns and processes of Müllerian mimicry, we integrate large-scale data on the geographical distribution of colour patterns of social bumblebees across the contiguous United States and use these to quantify colour pattern mimicry using an innovative, unsupervised machine-learning approach based on computer vision. Our data suggest that bumblebees exhibit geographically clustered, but sometimes imperfect colour patterns, and that mimicry patterns gradually transition spatially rather than exhibit discrete boundaries. Additionally, examination of colour pattern transition zones of three comimicking, polymorphic species, where active selection is driving phenotype frequencies, revealed that their transition zones differ in location within a broad region of poor mimicry. Potential factors influencing mimicry transition zone dynamics are discussed.

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.

scholarly journals Müllerian mimicry in bumble bees is a transient continuum

2019 ◽  
Author(s):  
Briana D. Ezray ◽  
Drew C. Wham ◽  
Carrie Hill ◽  
Heather M. Hines
Keyword(s):  
United States ◽  
Large Scale ◽  
The United States ◽  
Bumble Bees ◽  
Colour Pattern ◽  
Transition Zones ◽  
Müllerian Mimicry ◽  
Active Selection ◽  
Mullerian Mimicry ◽  
Colour Patterns

AbstractMüllerian mimicry theory states that frequency dependent selection should favour geographic convergence of harmful species onto a shared colour pattern. As such, mimetic patterns are commonly circumscribed into discrete mimicry complexes each containing a predominant phenotype. Outside a few examples in butterflies, the location of transition zones between mimicry complexes and the factors driving them has rarely been examined. To infer the patterns and processes of Müllerian mimicry, we integrate large-scale data on the geographic distribution of colour patterns of all social bumble bees across the contiguous United States and use these to quantify colour pattern mimicry using an innovative machine learning approach based on computer vision and image recognition. Our data suggests that bumble bees exhibit a manifold of similar, but imperfect colour patterns, that continuously transition across the United States, supporting the idea that mimicry is not discrete. We propose that bumble bees are mimicking a perceptual colour pattern average that is evolutionarily transient. We examine three comimicking polymorphic species,Bombus flavifrons, B. melanopygus,andB. bifarius, where active selection is driving colour pattern frequencies and determine that their colour pattern transition zones differ in location and breadth within a broad region of poor mimicry. Furthermore, we explore factors driving these differences such as mimicry selection dynamics and climate.

scholarly journals Prey community structure affects how predators select for Müllerian mimicry

2012 ◽  
Vol 279 (1736) ◽  
pp. 2099-2105 ◽  
Author(s):  
Eira Ihalainen ◽  
Hannah M. Rowland ◽  
Michael P. Speed ◽  
Graeme D. Ruxton ◽  
Johanna Mappes
Keyword(s):  
Prey Species ◽  
Generalization Test ◽  
Parus Major ◽  
Warning Signal ◽  
Specific Model ◽  
Müllerian Mimicry ◽  
Effective Community ◽  
Mullerian Mimicry ◽  
Specialist Predators ◽  
Signal Accuracy

Müllerian mimicry describes the close resemblance between aposematic prey species; it is thought to be beneficial because sharing a warning signal decreases the mortality caused by sampling by inexperienced predators learning to avoid the signal. It has been hypothesized that selection for mimicry is strongest in multi-species prey communities where predators are more prone to misidentify the prey than in simple communities. In this study, wild great tits ( Parus major ) foraged from either simple (few prey appearances) or complex (several prey appearances) artificial prey communities where a specific model prey was always present. Owing to slower learning, the model did suffer higher mortality in complex communities when the birds were inexperienced. However, in a subsequent generalization test to potential mimics of the model prey (a continuum of signal accuracy), only birds that had foraged from simple communities selected against inaccurate mimics. Therefore, accurate mimicry is more likely to evolve in simple communities even though predator avoidance learning is slower in complex communities. For mimicry to evolve, prey species must have a common predator; the effective community consists of the predator's diet. In diverse environments, the limited diets of specialist predators could create ‘simple community pockets’ where accurate mimicry is selected for.

scholarly journals Mimics here and there, but not everywhere: Müllerian mimicry in Ceroglossus ground beetles?

2016 ◽  
Vol 12 (9) ◽  
pp. 20160429 ◽  
Author(s):  
Carlos P. Muñoz-Ramírez ◽  
Pierre-Paul Bitton ◽  
Stéphanie M. Doucet ◽  
Lacey L. Knowles
Keyword(s):  
Phylogenetic Signal ◽  
Ground Beetle ◽  
Intraspecific Diversity ◽  
Apparent Lack ◽  
Müllerian Mimicry ◽  
Geographical Regions ◽  
Mullerian Mimicry ◽  
Colour Patterns ◽  
Apparent Colour ◽  
Colour Morphs

The ground beetle genus Ceroglossus contains co-distributed species that show pronounced intraspecific diversity in the form of geographical colour morphs. While colour morphs among different species appear to match in some geographical regions, in others, there is little apparent colour matching. Mimicry is a potential explanation for covariation in colour patterns, but it is not clear whether the degree of sympatric colour matching is higher than expected by chance given the obvious mismatches among morphs in some regions. Here, we used reflectance spectrometry to quantify elytral coloration from the perspective of an avian predator to test whether colour similarity between species is, indeed, higher in sympatry. After finding no significant phylogenetic signal in the colour data, analyses showed strong statistical support for sympatric colour similarity between species despite the apparent lack of colour matching in some areas. We hypothesize Müllerian mimicry as the responsible mechanism for sympatric colour similarity in Ceroglossus and discuss potential explanations and future directions to elucidate why mimicry has not developed similar levels of interspecific colour resemblance across space.

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