The metabolic cost of walking on an incline in the Peacock (<i>Pavo cristatus</i>)

Wilkinson, Holly N.; Thavarajah, Nathan; Codd, Jonathan R.

doi:10.7717/peerj.987

Cited by 3 publications

(2 citation statements)

References 81 publications

(139 reference statements)

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“…Adult peacocks are reported to have several effective anti-predator strategies, including running [135], flight [136], fighting with their sharp spurs [28], hiding in dense thickets [29,129,135], roosting in high trees chosen for their protection against predators at dusk [129,137], and using group vigilance along with alarm calling [138]. Consistent with this, three studies have shown that the peacock’s train does not significantly hinder locomotor performance during flight or walking; indeed, peacocks walking on a treadmill were efficient compared to other avian bipeds for which data exist and had a reduced metabolic cost during the breeding season when their trains were fully grown [136,139,140].…”

Section: Resultsmentioning

confidence: 95%

How conspicuous are peacock eyespots and other colorful feathers in the eyes of mammalian predators?

et al. 2019

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Colorful feathers have long been assumed to be conspicuous to predators, and hence likely to incur costs due to enhanced predation risk. However, many mammals that prey on birds have dichromatic visual systems with only two types of color-sensitive visual receptors, rather than the three and four photoreceptors characteristic of humans and most birds, respectively. Here, we use a combination of multispectral imaging, reflectance spectroscopy, color vision modelling and visual texture analysis to compare the visual signals available to conspecifics and to mammalian predators from multicolored feathers from the Indian peacock ( Pavo cristatus ), as well as red and yellow parrot feathers. We also model the effects of distance-dependent blurring due to visual acuity. When viewed by birds against green vegetation, most of the feathers studied are estimated to have color and brightness contrasts similar to values previously found for ripe fruit. On the other hand, for dichromat mammalian predators, visual contrasts for these feathers were only weakly detectable and often below detection thresholds for typical viewing distances. We also show that for dichromat mammal vision models, the peacock’s train has below-detection threshold color and brightness contrasts and visual textures that match various foliage backgrounds. These findings are consistent with many feathers of similar hue to those studied here being inconspicuous, and in some cases potentially cryptic, in the eyes of common mammalian predators of adult birds. Given that birds perform many conspicuous motions and behaviors, this study suggests that mammalian predators are more likely to use other sensory modalities (e.g., motion detection, hearing, and olfaction), rather than color vision, to detect avian prey. This suggests new directions for future behavioral studies and emphasizes the importance of understanding the influence of the sensory ecology of predators in the evolution of animal coloration.

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Section: Resultsmentioning

confidence: 95%

How conspicuous are peacock eyespots and other colorful feathers in the eyes of mammalian predators?

et al. 2019

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“…61 Hoyt 54 HumanHomo sapiens2.19–4.0230.09–46.410.25–0.3878.88–80.20−0.51Bransford and Howley 62 Hoyt 54 Rat-kangarooBettongia penicillata1.10–6.2081.80–114.390.05–0.100.9770.95Webster and Dawson 63 PeacockPavo cristatus0.5–1.019.15–16.610.49–0.794.581.43Wilkinson et al . 64 King penguinAptenodytes patagonicus0.08–0.5015.91–25.630.56–0.7911.5–11.6513.25Fahlman et al . 65 Present studySvalbard rock ptarmiganLagopus muta hyperborean0.22–0.7533.76–46.220.30–0.550.7329.3Lees et al .…”

Section: Methodsmentioning

confidence: 99%

Terrestrial locomotion energy costs vary considerably between species: no evidence that this is explained by rate of leg force production or ecology

Halsey

White

2019

Sci Rep

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Inter-specifically, relative energy costs of terrestrial transport vary several-fold. Many pair-wise differences of locomotor costs between similarly-sized species are considerable, and are yet to be explained by morphology or gait kinematics. Foot contact time, a proxy for rate of force production, is a strong predictor of locomotor energy costs across species of different size and might predict variability between similarly sized species. We tested for a relationship between foot contact time and metabolic rate during locomotion from published data. We investigated the phylogenetic correlation between energy expenditure rate and foot contact time, conditioned on fixed effects of mass and speed. Foot contact time does not explain variance in rate of energy expenditure during locomotion, once speed and body size are accounted for. Thus, perhaps surprisingly, inter-specific differences in the mass-independent net cost of terrestrial transport (NCOT) are not explained by rates of force production. We also tested for relationships between locomotor energy costs and eco-physiological variables. NCOT did not relate to any of the tested eco-physiological variables; we thus conclude either that interspecific differences in transport cost have no influence on macroecological and macrophysiological patterns, or that NCOT is a poor indicator of animal energy expenditure beyond the treadmill.

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How conspicuous are peacock eyespots and other colorful feathers in the eyes of mammalian predators?

Kane

Wang

Fang

et al. 2019

Preprint

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16Feathers perceived by humans to be vividly colorful are often presumed to be equally 17 conspicuous to other mammals, and thus to present an enhanced predation risk. However, many 18 mammals that prey on adult birds have dichromatic visual systems with only two types of color-19 sensitive visual receptors (one sensitive to ultraviolet light), rather than the three characteristic of 20 humans and four of most birds. Thus, understanding how these predators perceive color requires 21 quantitative visual modeling. Here, we use a combination of reflectance spectroscopy, 22 multispectral imaging, color vision modelling and visual texture analysis to compare the visual 2 23 signals available to conspecifics and to mammalian predators for multicolored feathers from the 24 Indian peacock (Pavo cristatus) as well as red and yellow parrot feathers; we also take into 25 account the effects of distance-dependent blurring due to visual acuity. When viewed by 26 tetrachromatic birds against a background of green vegetation, most of the feathers studied had 27 color and brightness contrasts similar to values previously found for ripe fruit. By contrast, 28 when viewed by dichromat mammalian predators, the color and brightness contrasts of these 29 feathers were only weakly detectable and often did not reach detection thresholds for typical 30 viewing distances. We furthermore show that the peacock's erect train has undetectable color 31 and brightness contrasts and visual textures when photographed against various foliage 32 backgrounds. Given the similarity of photoreceptor sensitivities and feather reflectance 33 properties across relevant species, these findings are consistent with many feathers of similar hue 34 being inconspicuous, and in some cases potentially cryptic, in the eyes of their mammalian 35 predators. These results suggest that many types of colorful feathers are likely to be cryptic to 36 mammals while providing a communication channel perceptible to birds, while emphasizing the 37 importance of understanding diverse sensory receivers in the evolution of animal coloration. 38 39 5 91predators with a variety of visual systems (Stevens and Merilaita, 2011). Our goal was to test the 92 assumption that colorful feathers that are highly conspicuous to conspecific birds are also readily 93 detectable by these predators. To determine how generalizable our results were to other hues of 94 colorful plumage, we also measured reflectance spectra and multispectral images of red and 95 yellow parrot feathers. We then used psychophysical vision models to test whether conspecifics 96 and dichromatic mammalian predators can readily detect the color and brightness contrasts 97 between feathers and green vegetation. Our analysis modeled the appearance of feathers at 98 various distances to determine when each observing species could distinguish color patches 99 relative to the surrounding environment. 100 101 In addition to color cues, visual salience depends on the presence of pattern features that are 102 perceptually discr...

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The metabolic cost of walking on an incline in the Peacock (Pavo cristatus)

Cited by 3 publications

References 81 publications

How conspicuous are peacock eyespots and other colorful feathers in the eyes of mammalian predators?

How conspicuous are peacock eyespots and other colorful feathers in the eyes of mammalian predators?

Terrestrial locomotion energy costs vary considerably between species: no evidence that this is explained by rate of leg force production or ecology

How conspicuous are peacock eyespots and other colorful feathers in the eyes of mammalian predators?

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