The influence of ultraviolet reflectance differs between conspicuous aposematic signals in neotropical butterflies and poison frogs

AbstractGeographic variation of color pattern in the South American poison frogs (Dendrobatidae) is an intriguing evolutionary phenomenon. These chemically defended anurans use bright aposematic colors to warn potential predators of their unpalatibility. However, aposematic signals are frequency-dependent and individuals deviating from a local model are at a higher risk of predation. The well-known examples of Batesian and Müllerian mimics, hymenopterans (wasps and bees) and Heliconius butterflies, both support the benefits of unique models with relatively high frequencies. However, extreme diversity in the aposematic signal has been documented in the poison frogs of the genus Dendrobates, especially in the Oophaga subgenus. Here we investigate the phylogenetic and genomic differentiations among populations of Oophaga sylvatica, which exhibit one of the highest phenotypic diversification among poison frogs. Using a combination of PCR amplicons (mitochondrial and nuclear markers) and genome wide markers from a double-digested RAD data set, we characterize 13 populations (12 monotypic and 1 polytypic) across the O. sylvatica distribution. These populations are mostly separated in two lineages distributed in the Northern and the Southern part of their range in Ecuador. We found relatively low genetic differentiation within each lineage, despite considerable phenotypic variation, and evidence suggesting ongoing gene flow and genetic admixture among some populations of the Northern lineage. Overall these data suggest that phenotypic diversification and novelty in aposematic coloration can arise in secondary contact zones even in systems where phenotypes are subject to strong stabilizing selection.

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Variable utility in the enigmatic presence of ultraviolet reflectance in conspicuous aposematic signals

10.22541/au.162499980.03470126/v1 ◽

2021 ◽

Author(s):

Justin Yeager ◽

James Barnett

Keyword(s):

Warning Signals ◽

Visual Modeling ◽

Visual Contrast ◽

Signal Efficacy ◽

Ultraviolet Reflectance ◽

Uv Reflectance ◽

Signal Contrast ◽

Intraspecific Communication ◽

Achromatic Contrast ◽

Aposematic Signals

Warning signals are often characterized by highly contrasting, distinctive and memorable colors. Both chromatic (hue) and achromatic (brightness) contrast contribute to signal efficacy, making longwave colored signals (red and yellow) that generate both chromatic and achromatic contrast common. Shortwave colors (blue and ultraviolet) do not contribute to luminance perception, yet are also common in warning signals. The presence of UV aposematic signals is paradoxical as UV perception is not universal, and evidence for its utility is at best mixed. We used visual modeling to quantify how UV affects signal contrast in aposematic butterflies and frogs. We found that UV only appreciably affected visual contrast in the butterflies. As the butterflies, but not the frogs, have UV-sensitive vision these results support the notion that UV reflectance is associated with intraspecific communication, but appears to be non-functional in frogs. Consequently, we should be careful when assigning a selection-based benefit from UV reflectance.

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Aposematism

10.1093/oso/9780199688678.003.0007 ◽

2018 ◽

Cited By ~ 2

Author(s):

Graeme D. Ruxton ◽

William L. Allen ◽

Thomas N. Sherratt ◽

Michael P. Speed

Keyword(s):

Secondary Effects ◽

Warning Coloration ◽

Common Features ◽

Initial Evolution ◽

The Common ◽

Aposematic Signals

Aposematism is the pairing of two kinds of defensive phenotype: an often repellent secondary defence that typically renders prey unprofitable to predators if they attack them and some evolved signal that indicates the presence of that defence. Aposematic signals often work to modify the behaviours of predators both before and during attacks. Warning coloration, for example, may increase wariness and hence improve the chances that a chemically defended prey is released unharmed after an attack. An aposematic signal may therefore first tend to reduce the probability that a predator commences attack (a primary defence) and then (as a component of secondary defence) reduce the probability that the prey is injured or killed during any subsequent attack. In this chapter we will consider both the primary and the secondary effects of aposematic signals on prey protection. We begin first by describing the common features of aposematic signals and attempting to show the wide use to which aposematic signalling is deployed across animals (and perhaps plants too). We then review the interesting evolutionary issues aposematic signals raise, including their initial evolution and their integration with sexual and other signals. We also discuss important ecological, co-evolutionary, and macroevolutionary consequences of aposematism.

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Silicon Nanotexture Surface Area Mapping Using Ultraviolet Reflectance

IEEE Journal of Photovoltaics ◽

10.1109/jphotov.2021.3086439 ◽

2021 ◽

pp. 1-8

Author(s):

Giuseppe Scardera ◽

David Payne ◽

Muhammad Umair Khan ◽

Yu Zhang ◽

Anastasia Soeriyadi ◽

...

Keyword(s):

Surface Area ◽

Ultraviolet Reflectance

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Far-Ultraviolet Reflectance Spectra and the Electronic Structure of Ionic Crystals

Physical Review B ◽

10.1103/physrevb.5.662 ◽

1972 ◽

Vol 5 (2) ◽

pp. 662-684 ◽

Cited By ~ 311

Author(s):

G. W. Rubloff

Keyword(s):

Electronic Structure ◽

Reflectance Spectra ◽

Ionic Crystals ◽

Ultraviolet Reflectance ◽

Far Ultraviolet

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Ultraviolet reflectance and female mating preferences in the common kestrel (Falco tinnunculus)

Canadian Journal of Zoology ◽

10.1139/z08-020 ◽

2008 ◽

Vol 86 (6) ◽

pp. 479-483 ◽

Cited By ~ 10

Author(s):

E. Zampiga ◽

G. Gaibani ◽

D. Csermely

Keyword(s):

Female Mate Choice ◽

Female Preference ◽

Visible Spectral Range ◽

Falco Tinnunculus ◽

Uv Filter ◽

Skin Reflectance ◽

Ultraviolet Reflectance ◽

Uv Reflectance ◽

Female Mating Preferences ◽

Uv Reflection

Previous studies revealed the importance of plumage brightness (considering only the visible spectral range) in female mate choice of common kestrels ( Falco tinnunculus L., 1758). Our study focuses on the effect of UV reflectance on female preference; we hypothesize that common kestrel females prefer males with UV-reflecting plumage and refuse, or are not attracted to, males whose plumage UV reflectance is prevented. We tested the preference of 20 captive females who were given a choice between two males, one behind a UV-transmitting (UV+) filter and another one behind a UV-blocking (UV–) filter. Female preference was measured as frequency and duration of visits to either male, specifically by sitting on the perch or hanging on to the partition wall. Females visited the male behind the UV+ filter more often than the male behind the UV– filter, indicating that females prefer males with UV-reflecting plumage than males without UV reflection. UV plumage and skin reflectance could provide females with information regarding current male conditions more so than other colours and other morphological parameters.

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Tropical poison frogs

Science ◽

10.1126/science.8235639 ◽

1993 ◽

Vol 262 (5137) ◽

pp. 1193-1193 ◽

Cited By ~ 4

Author(s):

C. Myers ◽

J. Daly

Keyword(s):

Poison Frogs

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Stabilizing selection on individual pattern elements of aposematic signals

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2017.0926 ◽

2017 ◽

Vol 284 (1861) ◽

pp. 20170926 ◽

Cited By ~ 17

Author(s):

Anne E. Winters ◽

Naomi F. Green ◽

Nerida G. Wilson ◽

Martin J. How ◽

Mary J. Garson ◽

...

Keyword(s):

Pattern Analysis ◽

Marine Organism ◽

Warning Signal ◽

Colour Pattern ◽

Stabilizing Selection ◽

Warning Signals ◽

Fish Predator ◽

Selection For ◽

Aposematic Signals ◽

Behavioural Experiments

Warning signal variation is ubiquitous but paradoxical: low variability should aid recognition and learning by predators. However, spatial variability in the direction and strength of selection for individual elements of the warning signal may allow phenotypic variation for some components, but not others. Variation in selection may occur if predators only learn particular colour pattern components rather than the entire signal. Here, we used a nudibranch mollusc, Goniobranchus splendidus , which exhibits a conspicuous red spot/white body/yellow rim colour pattern, to test this hypothesis. We first demonstrated that secondary metabolites stored within the nudibranch were unpalatable to a marine organism. Using pattern analysis, we demonstrated that the yellow rim remained invariable within and between populations; however, red spots varied significantly in both colour and pattern. In behavioural experiments, a potential fish predator, Rhinecanthus aculeatus , used the presence of the yellow rims to recognize and avoid warning signals. Yellow rims remained stable in the presence of high genetic divergence among populations. We therefore suggest that how predators learn warning signals may cause stabilizing selection on individual colour pattern elements, and will thus have important implications on the evolution of warning signals.

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