The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Peter T Madsen - One of the best experts on this subject based on the ideXlab platform.
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Acoustic Crypsis in southern right whale mother-calf pairs: infrequent, low-output calls to avoid predation?
The Journal of experimental biology, 2019Co-Authors: Mia L K Nielsen, Lars Bejder, Simone K A Videsen, Fredrik Christiansen, Peter T MadsenAbstract:Southern right whales (Eubalaena australis) invest substantial amounts of energy in their calves, while facing the risk of having them predated upon by eavesdropping killer whales (Orcinus orca). We tested the hypothesis that southern right whale mother-calf pairs employ acoustic Crypsis to reduce acoustic detectability by such predators. Specifically, we deployed multi-sensor DTAGs on nine lactating whales for a total of 62.9 h in a Western Australian breeding ground, and used a SoundTrap to estimate the concomitant acoustic background noise. Vocalisations were recorded at low rates of
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acoustic Crypsis in southern right whale mother calf pairs infrequent low output calls to avoid predation
The Journal of Experimental Biology, 2019Co-Authors: Mia L K Nielsen, Lars Bejder, Simone K A Videsen, Fredrik Christiansen, Peter T MadsenAbstract:ABSTRACT Southern right whales ( Eubalaena australis ) invest substantial amounts of energy in their calves, while facing the risk of having them predated upon by eavesdropping killer whales ( Orcinus orca ). We tested the hypothesis that southern right whale mother–calf pairs employ acoustic Crypsis to reduce acoustic detectability by such predators. Specifically, we deployed multi-sensor DTAGs on nine lactating whales for a total of 62.9 h in a Western Australian breeding ground, and used a SoundTrap to estimate the concomitant acoustic background noise. Vocalisations were recorded at low rates of −1 (1 call per dive) and at low received levels between 123±8 and 134±10 dB re. 1 µPa RMS depending on call type. We conclude that such acoustic Crypsis in southern right whales and other baleen whales decreases the risk of alerting potential predators and hence jeopardizing a substantial energetic investment by the mother.
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Acoustic Crypsis in southern right whale mother–calf pairs: infrequent, low-output calls to avoid predation?
The Journal of Experimental Biology, 2019Co-Authors: Mia L K Nielsen, Lars Bejder, Simone K A Videsen, Fredrik Christiansen, Peter T MadsenAbstract:ABSTRACT Southern right whales ( Eubalaena australis ) invest substantial amounts of energy in their calves, while facing the risk of having them predated upon by eavesdropping killer whales ( Orcinus orca ). We tested the hypothesis that southern right whale mother–calf pairs employ acoustic Crypsis to reduce acoustic detectability by such predators. Specifically, we deployed multi-sensor DTAGs on nine lactating whales for a total of 62.9 h in a Western Australian breeding ground, and used a SoundTrap to estimate the concomitant acoustic background noise. Vocalisations were recorded at low rates of −1 (1 call per dive) and at low received levels between 123±8 and 134±10 dB re. 1 µPa RMS depending on call type. We conclude that such acoustic Crypsis in southern right whales and other baleen whales decreases the risk of alerting potential predators and hence jeopardizing a substantial energetic investment by the mother.
Ian P.f. Owens - One of the best experts on this subject based on the ideXlab platform.
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evolution of color variation in dragon lizards quantitative tests of the role of Crypsis and local adaptation
Evolution, 2004Co-Authors: Devi Stuartfox, A Moussalli, G R Johnston, Ian P.f. OwensAbstract:Abstract Many animal species display striking color differences with respect to geographic location, sex, and body region. Traditional adaptive explanations for such complex patterns invoke an interaction between selection for conspicuous signals and natural selection for Crypsis. Although there is now a substantial body of evidence supporting the role of sexual selection for signaling functions, quantitative studies of Crypsis remain comparatively rare. Here, we combine objective measures of coloration with information on predator visual sensitivities to study the role of Crypsis in the evolution of color variation in an Australian lizard species complex (Ctenophorus decresii). We apply a model that allows us to quantify Crypsis in terms of the visual contrast of the lizards against their natural backgrounds, as perceived by potential avian predators. We then use these quantitative estimates of Crypsis to answer the following questions. Are there significant differences in Crypsis conspicuousness among p...
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Evolution of color variation in dragon lizards: Quantitative tests of the role of Crypsis and local adaptation
Evolution, 2004Co-Authors: D M Stuart-fox, A Moussalli, G R Johnston, Ian P.f. OwensAbstract:Many animal species display striking color differences with respect to geographic location, sex, and body region. Traditional adaptive explanations for such complex patterns invoke an interaction between selection for conspicuous signals and natural selection for Crypsis. Although there is now a substantial body of evidence supporting the role of sexual selection for signaling functions, quantitative studies of Crypsis remain comparatively rare. Here, we combine objective measures of coloration with information on predator visual sensitivities to study the role of Crypsis in the evolution of color variation in an Australian lizard species complex (Ctenophorus decresii). We apply a model that allows us to quantify Crypsis in terms of the visual contrast of the lizards against their natural backgrounds, as perceived by potential avian predators. We then use these quantitative estimates of Crypsis to answer the following questions. Are there significant differences in Crypsis conspicuousness among populations? Are there significant differences in Crypsis conspicuousness between the sexes? Are body regions "exposed" to visual predators more cryptic than "hidden" body regions? Is there evidence for local adaptation with respect to Crypsis against different substrates? In general, our results confirmed that there are real differences in Crypsis conspicuousness both between populations and between sexes; that exposed body regions were significantly more cryptic than hidden ones, particularly in females; and that females, but not males, are more cryptic against their own local background than against the background of other populations. Body regions that varied most in contrast between the sexes and between populations were also most conspicuous and are emphasized by males during social and sexual signaling. However, results varied with respect to the aspect of coloration studied. Results based on chromatic contrast ("hue" of color) provided better support for the Crypsis hypothesis than did results based on achromatic contrast ("brightness" of color). Taken together, these results support the view that Crypsis plays a substantial role in the evolution of color variation and that color patterns represent a balance between the need for conspicuousness for signaling and the need for Crypsis to avoid predation.
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Egg colouration and male parental effort in the pied flycatcher Ficedula hypoleuca\rEvolution of color variation in dragon lizards: Quantitative tests of the role of Crypsis and local adaptation
Journal of Avian Biology, 2004Co-Authors: J Moreno, G Tomas, D M Stuart-fox, A Moussalli, G R Johnston, Jose Luis Osorno, Susana Merino, J Morales, Ian P.f. OwensAbstract:A recent hypothesis posits that the bright colours of many avian eggs may act like signals of female genetic quality or condition to males in species with biparental care, inducing them to work harder for their offspring. We measured the colour of blue eggs of pied flycatchers Ficedula hypoleuca in Central Spain with a spectrophotometer on the day of laying, and also quantified the provisioning effort by males and females during the last days of the nestling period. Both chromaticity coordinates in the CIELAB colour space (blue to yellow, green to red) showed significant associations with male provisioning rates, explaining more than 20% of variation in male parental effort. Male provisioning rates were positively correlated with nestling condition, thereby potentially contributing to female fitness. This evidence is only tentative until experimental confirmation, but suggests that males are affected by the colour of their mates' eggs, a possibility not considered hitherto in the study of sexual selection. Many animal species display striking color differences with respect to geographic location, sex, and body region. Traditional adaptive explanations for such complex patterns invoke an interaction between selection for conspicuous signals and natural selection for Crypsis. Although there is now a substantial body of evidence supporting the role of sexual selection for signaling functions, quantitative studies of Crypsis remain comparatively rare. Here, we combine objective measures of coloration with information on predator visual sensitivities to study the role of Crypsis in the evolution of color variation in an Australian lizard species complex (Ctenophorus decresii). We apply a model that allows us to quantify Crypsis in terms of the visual contrast of the lizards against their natural backgrounds, as perceived by potential avian predators. We then use these quantitative estimates of Crypsis to answer the following questions. Are there significant differences in Crypsis conspicuousness among populations? Are there significant differences in Crypsis conspicuousness between the sexes? Are body regions "exposed" to visual predators more cryptic than "hidden" body regions? Is there evidence for local adaptation with respect to Crypsis against different substrates? In general, our results confirmed that there are real differences in Crypsis conspicuousness both between populations and between sexes; that exposed body regions were significantly more cryptic than hidden ones, particularly in females; and that females, but not males, are more cryptic against their own local background than against the background of other populations. Body regions that varied most in contrast between the sexes and between populations were also most conspicuous and are emphasized by males during social and sexual signaling. However, results varied with respect to the aspect of coloration studied. Results based on chromatic contrast ("hue" of color) provided better support for the Crypsis hypothesis than did results based on achromatic contrast ("brightness" of color). Taken together, these results support the view that Crypsis plays a substantial role in the evolution of color variation and that color patterns represent a balance between the need for conspicuousness for signaling and the need for Crypsis to avoid predation.
Andreas Rudh - One of the best experts on this subject based on the ideXlab platform.
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COARSE DARK PATTERNING FUNCTIONALLY CONSTRAINS ADAPTIVE SHIFTS FROM APOSEMATISM TO Crypsis IN STRAWBERRY POISON FROGS
Evolution, 2014Co-Authors: Anna Qvarnström, Andreas Rudh, Torkel Edström, Anders Ödeen, Hanne Løvlie, Birgitta S TullbergAbstract:Ecological specialization often requires tight coevolution of several traits, which may constrain future evolutionary pathways and make species more prone to extinction. Aposematism and Crypsis represent two specialized adaptations to avoid predation. We tested whether the combined effects of color and pattern on prey conspicuousness functionally constrain or facilitate shifts between these two adaptations. We combined data from 17 natural populations of strawberry poison frogs, Oophaga pumilio with an experimental approach using digitalized images of frogs and chickens as predators. We show that bright coloration often co-occurs with coarse patterning among the natural populations. Dull green frogs with coarse patterning are rare in nature but in the experiment they were as easily detected as bright red frogs suggesting that this trait combination represents a transient evolutionary state toward aposematism. Hence, a gain of either bright color or coarse patterning leads to conspicuousness, but a transition back to Crypsis would be functionally constrained in populations with both bright color and coarse patterning by requiring simultaneous changes in two traits. Thus, populations (or species) signaling aposematism by conspicuous color should be less likely to face an evolutionary dead end and more likely to radiate than populations with both conspicuous color and coarse patterning.
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Loss of conspicuous coloration has co-evolved with decreased body size in populations of poison dart frogs
Evolutionary Ecology, 2013Co-Authors: Andreas RudhAbstract:Larger signal size is known to facilitate the learning process of predators to warning signals. Further, smaller objects are generally harder to detect than large, which suggests that smaller sized prey are less likely to benefit from an aposematic strategy compared to Crypsis. However, whether body size changes in concert with shifts between Crypsis and aposematism in natural populations, remains largely unexplored. I tested whether body size was larger in visually conspicuous population than in cryptic populations among recently diverged populations of the Strawberry Poison frog, Oophaga pumilio. By analysing spectral reflectance and body size data from individuals from 18 discrete populations I found a larger mean body size in conspicuous populations, which was confirmed by an analysis of a subset of 12 populations accounting for phylogenetic history. This shows that the loss of conspicuous colour likely co-evolved repeatedly with a decrease in body size. Thus, selection on body size may influence evolutionary shifts between aposematism and Crypsis and vice versa.
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Pattern coarseness affects detectability of dull but not of conspicuously coloured poison frogs by an avian predator - implications for evolutionary transitions between aposematism and Crypsis
2012Co-Authors: Andreas Rudh, Torkel Edström, Anders Ödeen, Hanne Løvlie, Birgitta S Tullberg, Anna QvarnströmAbstract:Pattern coarseness affects detectability of dull but not of conspicuously coloured poison frogs by an avian predator - implications for evolutionary transitions between aposematism and Crypsis
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Aposematism, Crypsis and Population Differentiation in the Strawberry Poison Frog
2012Co-Authors: Andreas RudhAbstract:Evolutionary transitions between the two major predator avoidance strategies aposematism and Crypsis are expected to be associated with changes in many important traits of animals. However, empiric ...
Fredrik Christiansen - One of the best experts on this subject based on the ideXlab platform.
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Acoustic Crypsis in southern right whale mother-calf pairs: infrequent, low-output calls to avoid predation?
The Journal of experimental biology, 2019Co-Authors: Mia L K Nielsen, Lars Bejder, Simone K A Videsen, Fredrik Christiansen, Peter T MadsenAbstract:Southern right whales (Eubalaena australis) invest substantial amounts of energy in their calves, while facing the risk of having them predated upon by eavesdropping killer whales (Orcinus orca). We tested the hypothesis that southern right whale mother-calf pairs employ acoustic Crypsis to reduce acoustic detectability by such predators. Specifically, we deployed multi-sensor DTAGs on nine lactating whales for a total of 62.9 h in a Western Australian breeding ground, and used a SoundTrap to estimate the concomitant acoustic background noise. Vocalisations were recorded at low rates of
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acoustic Crypsis in southern right whale mother calf pairs infrequent low output calls to avoid predation
The Journal of Experimental Biology, 2019Co-Authors: Mia L K Nielsen, Lars Bejder, Simone K A Videsen, Fredrik Christiansen, Peter T MadsenAbstract:ABSTRACT Southern right whales ( Eubalaena australis ) invest substantial amounts of energy in their calves, while facing the risk of having them predated upon by eavesdropping killer whales ( Orcinus orca ). We tested the hypothesis that southern right whale mother–calf pairs employ acoustic Crypsis to reduce acoustic detectability by such predators. Specifically, we deployed multi-sensor DTAGs on nine lactating whales for a total of 62.9 h in a Western Australian breeding ground, and used a SoundTrap to estimate the concomitant acoustic background noise. Vocalisations were recorded at low rates of −1 (1 call per dive) and at low received levels between 123±8 and 134±10 dB re. 1 µPa RMS depending on call type. We conclude that such acoustic Crypsis in southern right whales and other baleen whales decreases the risk of alerting potential predators and hence jeopardizing a substantial energetic investment by the mother.
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Acoustic Crypsis in southern right whale mother–calf pairs: infrequent, low-output calls to avoid predation?
The Journal of Experimental Biology, 2019Co-Authors: Mia L K Nielsen, Lars Bejder, Simone K A Videsen, Fredrik Christiansen, Peter T MadsenAbstract:ABSTRACT Southern right whales ( Eubalaena australis ) invest substantial amounts of energy in their calves, while facing the risk of having them predated upon by eavesdropping killer whales ( Orcinus orca ). We tested the hypothesis that southern right whale mother–calf pairs employ acoustic Crypsis to reduce acoustic detectability by such predators. Specifically, we deployed multi-sensor DTAGs on nine lactating whales for a total of 62.9 h in a Western Australian breeding ground, and used a SoundTrap to estimate the concomitant acoustic background noise. Vocalisations were recorded at low rates of −1 (1 call per dive) and at low received levels between 123±8 and 134±10 dB re. 1 µPa RMS depending on call type. We conclude that such acoustic Crypsis in southern right whales and other baleen whales decreases the risk of alerting potential predators and hence jeopardizing a substantial energetic investment by the mother.
Lars Bejder - One of the best experts on this subject based on the ideXlab platform.
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Acoustic Crypsis in southern right whale mother-calf pairs: infrequent, low-output calls to avoid predation?
The Journal of experimental biology, 2019Co-Authors: Mia L K Nielsen, Lars Bejder, Simone K A Videsen, Fredrik Christiansen, Peter T MadsenAbstract:Southern right whales (Eubalaena australis) invest substantial amounts of energy in their calves, while facing the risk of having them predated upon by eavesdropping killer whales (Orcinus orca). We tested the hypothesis that southern right whale mother-calf pairs employ acoustic Crypsis to reduce acoustic detectability by such predators. Specifically, we deployed multi-sensor DTAGs on nine lactating whales for a total of 62.9 h in a Western Australian breeding ground, and used a SoundTrap to estimate the concomitant acoustic background noise. Vocalisations were recorded at low rates of
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acoustic Crypsis in southern right whale mother calf pairs infrequent low output calls to avoid predation
The Journal of Experimental Biology, 2019Co-Authors: Mia L K Nielsen, Lars Bejder, Simone K A Videsen, Fredrik Christiansen, Peter T MadsenAbstract:ABSTRACT Southern right whales ( Eubalaena australis ) invest substantial amounts of energy in their calves, while facing the risk of having them predated upon by eavesdropping killer whales ( Orcinus orca ). We tested the hypothesis that southern right whale mother–calf pairs employ acoustic Crypsis to reduce acoustic detectability by such predators. Specifically, we deployed multi-sensor DTAGs on nine lactating whales for a total of 62.9 h in a Western Australian breeding ground, and used a SoundTrap to estimate the concomitant acoustic background noise. Vocalisations were recorded at low rates of −1 (1 call per dive) and at low received levels between 123±8 and 134±10 dB re. 1 µPa RMS depending on call type. We conclude that such acoustic Crypsis in southern right whales and other baleen whales decreases the risk of alerting potential predators and hence jeopardizing a substantial energetic investment by the mother.
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Acoustic Crypsis in southern right whale mother–calf pairs: infrequent, low-output calls to avoid predation?
The Journal of Experimental Biology, 2019Co-Authors: Mia L K Nielsen, Lars Bejder, Simone K A Videsen, Fredrik Christiansen, Peter T MadsenAbstract:ABSTRACT Southern right whales ( Eubalaena australis ) invest substantial amounts of energy in their calves, while facing the risk of having them predated upon by eavesdropping killer whales ( Orcinus orca ). We tested the hypothesis that southern right whale mother–calf pairs employ acoustic Crypsis to reduce acoustic detectability by such predators. Specifically, we deployed multi-sensor DTAGs on nine lactating whales for a total of 62.9 h in a Western Australian breeding ground, and used a SoundTrap to estimate the concomitant acoustic background noise. Vocalisations were recorded at low rates of −1 (1 call per dive) and at low received levels between 123±8 and 134±10 dB re. 1 µPa RMS depending on call type. We conclude that such acoustic Crypsis in southern right whales and other baleen whales decreases the risk of alerting potential predators and hence jeopardizing a substantial energetic investment by the mother.