Search results for "EVOLUTION"
showing 10 items of 11096 documents
Transparency reduces predator detection in mimetic clearwing butterflies
2019
International audience; Predation is an important selective pressure and some prey have evolved conspicuous warning signals that advertise unpalatability (i.e. aposematism) as an antipredator defence. Conspicuous colour patterns have been shown effective as warning signals, by promoting predator learning and memory. Unexpectedly, some butterfly species from the unpalatable tribe Ithomiini possess transparent wings, a feature rare on land but common in water, known to reduce predator detection.We tested if transparency of butterfly wings was associated with decreased detectability by predators, by comparing four butterfly species exhibiting different degrees of transparency, ranging from ful…
Safety in Numbers: How Color Morph Frequency Affects Predation Risk in an Aposematic Moth
2021
Polymorphic warning signals in aposematic systems are enigmatic because predator learning should favor the most common form, creating positive frequency-dependent survival. However, many populations exhibit variation in warning signals. There are various selective mechanisms that can counter positive frequency-dependent selection and lead to temporal or spatial warning signal diversification. Examining these mechanisms and their effects requires first confirming whether the most common morphs are favored at both local and regional scales. Empirical examples of this are uncommon and often include potentially confounding factors, such as a lack of knowledge of predator identity and behavior. …
The Effect of Predator Population Dynamics on Batesian Mimicry Complexes.
2022
Understanding Batesian mimicry is a classic problem in evolutionary biology. In Batesian mimicry, a defended species (the model) is mimicked by an undefended species (the mimic). Prior theories have emphasized the role of predator behavior and learning as well as evolution in model-mimic complexes but have not examined the role of population dynamics in potentially governing the relative abundances and even persistence of model-mimic systems. Here, we examined the effect of the population dynamics of predators and alternative prey on the prevalence of warning-signaling prey composed of models and mimics. Using optimal foraging theory and signal detection theory, we found that the inclusion …
Heterozygote advantage and pleiotropy contribute to intraspecific color trait variability
2022
The persistence of intrapopulation phenotypic variation typically requires some form of balancing selection because drift and directional selection eventually erode genetic variation. Heterozygote advantage remains a classic explanation for the maintenance of genetic variation in the face of selection. However, examples of heterozygote advantage, other than those associated with disease resistance, are rather uncommon. Across most of its distribution, males of the aposematic moth Arctia plantaginis have two hindwing phenotypes determined by a heritable one locus-two allele polymorphism (genotypes: WW/Wy = white morph, yy = yellow morph). Using genotyped moths, we show that the presence of o…
Predator-Induced Plasticity on Warning Signal and Larval Life-History Traits of the Aposematic Wood Tiger Moth, Arctia plantaginis
2021
Correction Frontiers in Ecology and Evolution Volume 9 Article Number 737651 DOI 10.3389/fevo.2021.737651 Published JUL 29 2021 Predator-induced plasticity in life-history and antipredator traits during the larval period has been extensively studied in organisms with complex life-histories. However, it is unclear whether different levels of predation could induce warning signals in aposematic organisms. Here, we investigated whether predator-simulated handling affects warning coloration and life-history traits in the aposematic wood tiger moth larva, Arctia plantaginis. As juveniles, a larger orange patch on an otherwise black body signifies a more efficient warning signal against predators…
Sole coloration as an unusual aposematic signal in a Neotropical toad
2019
Many animals have evolved remarkable strategies to avoid predation. In diurnal, toxic harlequin toads (Atelopus) from the Amazon basin, we find a unique colour signal. Some Atelopus populations have striking red soles of the hands and feet, visible only when walking. When stationary, the toads are hard to detect despite their yellow-black dorsal coloration. Consequently, they switch between high and low conspicuousness. Interestingly, some populations lack the extra colour display of the soles. We found comprehensive support that the red coloration can act as an aposematic signal directed towards potential predators: red soles are significantly more conspicuous than soles lacking red colora…
Evolution of signal diversity: predator-prey interactions and the maintenance of warning colour polymorphism in the wood tiger moth Arctia plantaginis
2017
Aposematic organisms avoid predation by advertising defences with warning signals. The theory of aposematism predicts warning signal uniformity, yet variation in warning coloration is widespread. The chemically defended wood tiger moth Arctia plantaginis shows both geographic variation and local polymorphism in warning coloration. In this thesis, I studied whether predation by local avian predators is driving the evolution of wood tiger moth warning colours. The close relatives of the wood tiger moth designated here to genus Arctia do not show similar colour polymorphism. The wood tiger moth is thus apparently under evolutionary radiation and provides a natural laboratory for observing curr…
The impact of life stage and pigment source on the evolution of novel warning signal traits
2021
Our understanding of how novel warning color traits evolve in natural populations is largely based on studies of reproductive stages and organisms with endogenously produced pigmentation. In these systems, genetic drift is often required for novel alleles to overcome strong purifying selection stemming from frequency-dependent predation and positive assortative mating. Here, we integrate data from field surveys, predation experiments, population genomics, and phenotypic correlations to explain the origin and maintenance of geographic variation in a diet-based larval pigmentation trait in the redheaded pine sawfly (Neodiprion lecontei), a pine-feeding hymenopteran. Although our experiments c…
Diversity in warning coloration: selective paradox or the norm?
2019
Aposematic theory has historically predicted that predators should select for warning signals to converge on a single form, as a result of frequency-dependent learning. However, widespread variation in warning signals is observed across closely related species, populations and, most problematically for evolutionary biologists, among individuals in the same population. Recent research has yielded an increased awareness of this diversity, challenging the paradigm of signal monomorphy in aposematic animals. Here we provide a comprehensive synthesis of these disparate lines of investigation, identifying within them three broad classes of explanation for variation in aposematic warning signals: …
Appearance before performance? : Nutritional constraints on life‐history traits, but not warning signal expression in aposematic moths
2020
1.Trade‐offs have been shown to play an important role in the divergence of mating strategies and sexual ornamentation, but their importance in explaining warning signal diversity has received less attention. In aposematic organisms, allocation costs of producing the conspicuous warning signal pigmentation under nutritional stress could potentially trade‐off with life‐history traits and maintain variation in warning colouration. 2. We studied this with an aposematic herbivore Arctia plantaginis (Arctiidae), whose larvae and adults show extensive variation in aposematic colouration. In larvae, less melanic colouration (i.e. larger orange patterns) produces a more efficient warning signal aga…