Blue reflectance in tarantulas is evolutionarily conserved despite nanostructural diversity

Hsiung, Bor-Kai; Deheyn, Dimitri D.; Shawkey, Matthew D.; Blackledge, Todd A.

doi:10.1126/sciadv.1500709

Cited by 43 publications

(65 citation statements)

References 58 publications

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“…A recent evolutionary study documented many apparently independent evolutionary origins of the caecal appendix in mammals; thus the convergent evolution of unusual anatomical structures like the osseous patella has precedent (Smith et al, 2013). Similarly, blue colouration among tarantula spiders apparently involved at least eight independent evolutionary acquisitions, among different microscopic anatomical structures affecting spectral reflectance and hence general external colour (Hsiung et al, 2015). A better understanding of the genomic signatures required for development of such novel structures should be very helpful to deconstruct the observed complex patterns of evolution, distinguishing between convergent evolution (homoplasy) and shared inheritance (synapomorphy/homology).…”

Section: Resultsmentioning

confidence: 99%

Evolution of the patellar sesamoid bone in mammals

Samuels

Regnault

Hutchinson

2017

PeerJ

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The patella is a sesamoid bone located in the major extensor tendon of the knee joint, in the hindlimb of many tetrapods. Although numerous aspects of knee morphology are ancient and conserved among most tetrapods, the evolutionary occurrence of an ossified patella is highly variable. Among extant (crown clade) groups it is found in most birds, most lizards, the monotreme mammals and almost all placental mammals, but it is absent in most marsupial mammals as well as many reptiles. Here, we integrate data from the literature and first-hand studies of fossil and recent skeletal remains to reconstruct the evolution of the mammalian patella. We infer that bony patellae most likely evolved between four and six times in crown group Mammalia: in monotremes, in the extinct multituberculates, in one or more stem-mammal genera outside of therian or eutherian mammals and up to three times in therian mammals. Furthermore, an ossified patella was lost several times in mammals, not including those with absent hindlimbs: once or more in marsupials (with some re-acquisition) and at least once in bats. Our inferences about patellar evolution in mammals are reciprocally informed by the existence of several human genetic conditions in which the patella is either absent or severely reduced. Clearly, development of the patella is under close genomic control, although its responsiveness to its mechanical environment is also important (and perhaps variable among taxa). Where a bony patella is present it plays an important role in hindlimb function, especially in resisting gravity by providing an enhanced lever system for the knee joint. Yet the evolutionary origins, persistence and modifications of a patella in diverse groups with widely varying habits and habitats—from digging to running to aquatic, small or large body sizes, bipeds or quadrupeds—remain complex and perplexing, impeding a conclusive synthesis of form, function, development and genetics across mammalian evolution. This meta-analysis takes an initial step toward such a synthesis by collating available data and elucidating areas of promising future inquiry.

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Section: Resultsmentioning

confidence: 99%

Evolution of the patellar sesamoid bone in mammals

Samuels

Regnault

Hutchinson

2017

PeerJ

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“…We previously determined that the refractive index (n r ) for spider cuticle is ∼1.60 (Hsiung et al, 2015b). Therefore, either ethyl cinnamate (n r ≈1.56, W243019, Sigma-Aldrich) or quinoline (n r ≈1.63, 241571, Sigma-Aldrich) was used as an index-matching solution.…”

Section: Refractive Index Matchingmentioning

confidence: 99%

“…A Maratus anomalus opisthosoma cuticle fragment was dehydrated and washed, followed by epoxy resin infiltration and embedding based on a previously reported protocol (Hsiung et al, 2015b). The cured epoxy block was trimmed with a Leica EM TRIM2 (Leica Microsystems) and microtomed into 80 nm thin sections using a Leica EM UC6 (Leica Microsystems) with a DiATOME diamond knife (Electron Microscopy Sciences, Hatfield, PA, USA).…”

Section: Transmission Electron Microscopy (Tem)mentioning

confidence: 99%

“…Pigmentary colours are independent of viewing angle (non-iridescent), while structural colours are usually angle dependent (iridescent). The nanomorphology of structural colours has been investigated recently for some spiders (Foelix et al, 2013;Hsiung et al, 2015b;Ingram et al, 2011;Land et al, 2007;Simonis et al, 2013;Stavenga et al, 2016). However, our knowledge of spider pigment biochemistry has remained stagnant for almost 30 years (Holl, 1987, but see Hsiung et al, 2015a).…”

Section: Introductionmentioning

confidence: 99%

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Spiders have rich pigmentary and structural colour palettes

Hsiung

Justyn

Blackledge

et al. 2017

Journal of Experimental Biology

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Elucidating the mechanisms of colour production in organisms is important for understanding how selection acts upon a variety of behaviours. Spiders provide many spectacular examples of colours used in courtship, predation, defence and thermoregulation, but are thought to lack many types of pigments common in other animals. Ommochromes, bilins and eumelanin have been identified in spiders, but not carotenoids or melanosomes. Here, we combined optical microscopy, refractive index matching, confocal Raman microspectroscopy and electron microscopy to investigate the basis of several types of colourful patches in spiders. We obtained four major results. First, we show that spiders use carotenoids to produce yellow, suggesting that such colours may be used for conditiondependent courtship signalling. Second, we established the Raman signature spectrum for ommochromes, facilitating the identification of ommochromes in a variety of organisms in the future. Third, we describe a potential new pigmentary-structural colour interaction that is unusual because of the use of long wavelength structural colour in combination with a slightly shorter wavelength pigment in the production of red. Finally, we present the first evidence for the presence of melanosomes in arthropods, using both scanning and transmission electron microscopy, overturning the assumption that melanosomes are a synapomorphy of vertebrates. Our research shows that spiders have a much richer colour production palette than previously thought, and this has implications for colour diversification and function in spiders and other arthropods.

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“…Lamellated hairs, consisting of chitin and air thin films or quasi-ordered structures, act as blue reflectors in tarantulas, Theraphosidae [4,10,16]. A specifically interesting theraphosid, Poecilotheria metallica, features in addition to the blue hairs slightly differently organized, pigmentless hairs, which exhibit a yellow structural colour [4].…”

Section: Introductionmentioning

confidence: 99%

Splendid coloration of the peacock spider Maratus splendens

Stavenga

Otto²,

Wilts

2016

J. R. Soc. Interface.

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Jumping spiders are well known for their acute vision and often bright colours. The male peacock spider Maratus splendens is richly coloured by scales that cover the body. The colours of the white, cream and red scales, which have an elaborate shape with numerous spines, are pigmentary. Blue scales are unpigmented and have a structural colour, created by an intricate photonic system consisting of two chitinous layers with ridges, separated by an air gap, with on the inner sides of the chitin layers an array of filaments. We have characterized the optical properties of the scales by microspectrophotometry, imaging scatterometry and light and scanning electron microscopy. Optical modelling revealed that the filament array constitutes a novel structural coloration system, which subtly fine tunes the scale reflectance to the observed blue coloration.

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Blue reflectance in tarantulas is evolutionarily conserved despite nanostructural diversity

Abstract: Natural selection on structural color in tarantulas resulted in convergence on color through diverse structural mechanisms.

Cited by 43 publications

References 58 publications

Evolution of the patellar sesamoid bone in mammals

Evolution of the patellar sesamoid bone in mammals

Spiders have rich pigmentary and structural colour palettes

Splendid coloration of the peacock spider Maratus splendens

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