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John Egan, Rebecca J Sharman, Kenneth C Scott-Brown, Paul George Lovell
Disruptive colouration is a visual camouflage composed of false edges and boundaries. Many disruptively camouflaged animals feature enhanced edges; light patches are surrounded by a lighter outline and/or a dark patches are surrounded by a darker outline. This camouflage is particularly common in amphibians, reptiles and lepidopterans. We explored the role that this pattern has in creating effective camouflage. In a visual search task utilising an ultra-large display area mimicking search tasks that might be found in nature, edge enhanced disruptive camouflage increases crypsis, even on substrates that do not provide an obvious visual match...
December 6, 2016: Scientific Reports
Martin Bulla, Mihai Valcu, Adriaan M Dokter, Alexei G Dondua, András Kosztolányi, Anne L Rutten, Barbara Helm, Brett K Sandercock, Bruce Casler, Bruno J Ens, Caleb S Spiegel, Chris J Hassell, Clemens Küpper, Clive Minton, Daniel Burgas, David B Lank, David C Payer, Egor Y Loktionov, Erica Nol, Eunbi Kwon, Fletcher Smith, H River Gates, Hana Vitnerová, Hanna Prüter, James A Johnson, James J H St Clair, Jean-François Lamarre, Jennie Rausch, Jeroen Reneerkens, Jesse R Conklin, Joanna Burger, Joe Liebezeit, Joël Bêty, Jonathan T Coleman, Jordi Figuerola, Jos C E W Hooijmeijer, José A Alves, Joseph A M Smith, Karel Weidinger, Kari Koivula, Ken Gosbell, Klaus-Michael Exo, Larry Niles, Laura Koloski, Laura McKinnon, Libor Praus, Marcel Klaassen, Marie-Andrée Giroux, Martin Sládeček, Megan L Boldenow, Michael I Goldstein, Miroslav Šálek, Nathan Senner, Nelli Rönkä, Nicolas Lecomte, Olivier Gilg, Orsolya Vincze, Oscar W Johnson, Paul A Smith, Paul F Woodard, Pavel S Tomkovich, Phil F Battley, Rebecca Bentzen, Richard B Lanctot, Ron Porter, Sarah T Saalfeld, Scott Freeman, Stephen C Brown, Stephen Yezerinac, Tamás Székely, Tomás Montalvo, Theunis Piersma, Vanessa Loverti, Veli-Matti Pakanen, Wim Tijsen, Bart Kempenaers
The behavioural rhythms of organisms are thought to be under strong selection, influenced by the rhythmicity of the environment. Such behavioural rhythms are well studied in isolated individuals under laboratory conditions, but free-living individuals have to temporally synchronize their activities with those of others, including potential mates, competitors, prey and predators. Individuals can temporally segregate their daily activities (for example, prey avoiding predators, subordinates avoiding dominants) or synchronize their activities (for example, group foraging, communal defence, pairs reproducing or caring for offspring)...
December 1, 2016: Nature
John W Rowe, David L Clark, Rebecca A Mortensen, Carolyn V Commissaris, Lawrence W Wittle, John K Tucker
Color and pigmentation patterns of the integument can facilitate crypsis, thermoregulation, and social signaling. According to the "thermal melanism hypothesis", cold environmental temperature should increase the quantity of melanin that is deposited in the integument thereby facilitating radiative warming. We studied the influences of water temperature (26°C or 31°C) and substrate color (black or white) on the degree of melanization in the red-eared slider, Trachemys scripta elegans, under laboratory conditions...
October 2016: Journal of Thermal Biology
C M Champ, M Vorobyev, N J Marshall
Coral reef fishes are among the most colourful animals in the world. Given the diversity of lifestyles and habitats on the reef, it is probable that in many instances coloration is a compromise between crypsis and communication. However, human observation of this coloration is biased by our primate visual system. Most animals have visual systems that are 'tuned' differently to humans; optimized for different parts of the visible spectrum. To understand reef fish colours, we need to reconstruct the appearance of colourful patterns and backgrounds as they are seen through the eyes of fish...
September 2016: Royal Society Open Science
R Alexander Pyron, Alejandro Arteaga, Lourdes Y Echevarría, Omar Torres-Carvajal
The genus Synophis contains a number of enigmatic species, distributed primarily in the Andean highlands of northern South America. Their extreme crypsis and rarity has precluded detailed study of most species. A recent flurry of collection activity resulted in the accession of many new specimens, and the description of 4 new species in 2015, doubling the number of described taxa. However, lingering questions remain regarding the assignment of many new and historical specimens, the morphological limits and geographical ranges of the species, and their phylogenetic relationships...
September 28, 2016: Zootaxa
W Clark, E Leclercq, H Migaud, J Nairn, A Davie
This study confirmed that observations of blue-green colouration in plasma fractions of the ballan wrasse Labrus bergylta were caused by the linear tetra-pyrrole biliverdin and that the molecule was of the physiologically relevant IXα isomer. Accumulation appears driven by chromogenic association with an unknown protein moiety which precludes enzymatic reduction and would suggest active management. It was demonstrated that the pigment did not fluctuate relative to ontogeny, or indeed binary gender in the species of interest, but mobilisation and depletion in the subset of individuals undergoing sex change at the time of study supports a potential association with gender inversion processes...
October 2016: Journal of Fish Biology
Fabio Cortesi, Zuzana Musilová, Sara M Stieb, Nathan S Hart, Ulrike E Siebeck, Karen L Cheney, Walter Salzburger, N Justin Marshall
Animals often change their habitat throughout ontogeny; yet, the triggers for habitat transitions and how these correlate with developmental changes - e.g. physiological, morphological and behavioural - remain largely unknown. Here, we investigated how ontogenetic changes in body coloration and of the visual system relate to habitat transitions in a coral reef fish. Adult dusky dottybacks, Pseudochromis fuscus, are aggressive mimics that change colour to imitate various fishes in their surroundings; however, little is known about the early life stages of this fish...
August 15, 2016: Journal of Experimental Biology
Chris B Wacker, Bronwyn M McAllan, Gerhard Körtner, Fritz Geiser
Mammalian fur often shows agouti banding with a proximal dark band near the skin and a lighter distal band. We examined the function of both bands in relation to camouflage, thermal properties of pelts, and thermal energetics of dunnarts (Sminthopsis crassicaudata), which are known to use torpor and basking. Although the distal band of dunnart fur darkened with increasing latitude, which is important for camouflage, it did not affect the thermal properties and the length of the dark band and total hair length were not correlated...
August 2016: Die Naturwissenschaften
Haruhiko Yasumuro, Yuzuru Ikeda
We examined effect of environmental enrichment on cuttlefish, the most neutrally advanced invertebrate, to compare species variation of genetic and environmental influences. Cuttlefish were reared from seven to 117 days in one of three environments, namely, "poor" (artificial bottom without objects), "standard" (sandy bottom), and "enriched" (sandy bottom with objects). In Experiment 1, we explored whether enrichment affects the exhibition of crypsis in the cuttlefish. The cuttlefish in the standard and enriched environments spent most of their time at the bottom, exhibiting the mottled or disruptive pattern starting at 27 days of age...
June 2016: Zoological Science
Nicola J Nadeau, Carolina Pardo-Diaz, Annabel Whibley, Megan A Supple, Suzanne V Saenko, Richard W R Wallbank, Grace C Wu, Luana Maroja, Laura Ferguson, Joseph J Hanly, Heather Hines, Camilo Salazar, Richard M Merrill, Andrea J Dowling, Richard H ffrench-Constant, Violaine Llaurens, Mathieu Joron, W Owen McMillan, Chris D Jiggins
The wing patterns of butterflies and moths (Lepidoptera) are diverse and striking examples of evolutionary diversification by natural selection. Lepidopteran wing colour patterns are a key innovation, consisting of arrays of coloured scales. We still lack a general understanding of how these patterns are controlled and whether this control shows any commonality across the 160,000 moth and 17,000 butterfly species. Here, we use fine-scale mapping with population genomics and gene expression analyses to identify a gene, cortex, that regulates pattern switches in multiple species across the mimetic radiation in Heliconius butterflies...
June 1, 2016: Nature
Theodore Stankowich, Lisa A Campbell
Mammals have independently evolved a wide variety of morphological adaptations for use in avoiding death by predation, including spines, quills, dermal plates, and noxious sprays. Although these traits appear to protect their bearer from predatory attack, it is less obvious why some species evolved them and others have not. We investigated the ecological correlates favoring the evolution of specialized defenses in mammals, focusing on conspicuousness to predators due to body size and openness of habitat. We scored species for the degree to which they are protected by spines, quills, dermal plating, and sprays and used phylogenetic comparative analyses to study the morphological and ecological factors that may favor their evolution...
July 2016: Evolution; International Journal of Organic Evolution
Eric F LoPresti, Richard Karban
Sand entrapment on plant surfaces, termed psammophory or sand armor, is a phylogenetically and geographically widespread trait. The functional significance of this phenomenon has been poorly investigated. Sand and soil are nonnutritive and difficult for herbivores to process, as well as visually identical to the background. We experimentally investigated whether this sand coating physically protected the plant from herbivores or increased crypsis (e.g., decreased apparency to herbivores). We tested the former hypothesis by removing entrapped sand from stems, petioles, and leaves of the sand verbena Abronia latifolia and by supplementing natural sand levels in the honeyscented pincushion plant Navarretia mellita...
April 2016: Ecology
Rafael Maia, Dustin R Rubenstein, Matthew D Shawkey
Colorful plumage plays a prominent role in the evolution of birds, influencing communication (sexual/social selection), and crypsis (natural selection). Comparative studies have focused primarily on these selective pressures, but the mechanisms underlying color production can also be important by constraining the color gamut upon which selection acts. Iridescence is particularly interesting to study the interaction between selection and color-producing mechanisms because a broad range of colors can be produced with a shared template, and innovations to this template further expand this by increasing the parameters interacting to produce colors...
May 2016: Evolution; International Journal of Organic Evolution
Petra Sumasgutner, Gareth J Tate, Ann Koeslag, Arjun Amar
From an evolutionary perspective, recruitment into the breeding population represents one of the most important life-history stages and ultimately determines the effective population size. In order to contribute to the next generation, offspring must survive to sexual maturity, secure a territory and find a mate. In this study, we explore factors influencing both offspring survival and their subsequent recruitment into the local breeding population in a long-lived urban raptor, the black sparrowhawk (Accipiter melanoleucus)...
July 2016: Journal of Animal Ecology
H F Swift, L Gómez Daglio, M N Dawson
Evolutionary inference can be complicated by morphological crypsis, particularly in open marine systems that may rapidly dissipate signals of evolutionary processes. These complications may be alleviated by studying systems with simpler histories and clearer boundaries, such as marine lakes-small bodies of seawater entirely surrounded by land. As an example, we consider the jellyfish Mastigias spp. which occurs in two ecotypes, one in marine lakes and one in coastal oceanic habitats, throughout the Indo-West Pacific (IWP)...
June 2016: Molecular Phylogenetics and Evolution
Sandra L Ament-Velásquez, Odalisca Breedy, Jorge Cortés, Hector M Guzman, Gert Wörheide, Sergio Vargas
Octocorals are a diverse and ecologically important group of cnidarians. However, the phylogenetic relationships of many octocoral groups are not well understood and are based mostly on mitochondrial sequence data. In addition, the discovery and description of new gorgonian species displaying unusual or intermediate morphologies and uncertain phylogenetic affinities further complicates the study of octocoral systematics and raises questions about the role played by processes such as plasticity, crypsis, and convergence in the evolution of this group of organisms...
May 2016: Molecular Phylogenetics and Evolution
Olivier Penacchio, Innes C Cuthill, P George Lovell, Graeme D Ruxton, Julie M Harris
Orientation with respect to the sun has been observed in a wide range of species and has generally been interpreted in terms of thermoregulation and/or ultraviolet (UV) protection. For countershaded animals, orientation with respect to the sun may also result from the pressure to exploit the gradient of coloration optimally to enhance crypsis.Here, we use computational modelling to predict the optimal countershading pattern for an oriented body. We assess how camouflage performance declines as orientation varies using a computational model that incorporates realistic lighting environments...
September 2015: Functional Ecology
H Priti, Rekha Sarma Roshmi, Badrinath Ramya, H S Sudhira, G Ravikanth, Neelavara Anantharam Aravind, Kotambylu Vasudeva Gururaja
A new cryptic species of bush frog Raorchestes honnametti sp. nov. is described from the south-eastern part of the Western Ghats, India. This newly described species belongs to the Charius clade and is morphologically similar to other clade members--R. charius and R. griet. Therefore, an integrative taxonomic approach based on molecular and bioacoustic analysis along with morphology was used to delimit the new species. Raorchestes honnametti sp. nov., is currently known only from Biligiri Rangaswamy Temple Tiger Reserve, a part of Biligiri Rangaswamy horst mountain range (a mountain formed due movement of two faults) formed during the Late Quaternary period (1...
2016: PloS One
Thomas Dejaco, Melitta Gassner, Wolfgang Arthofer, Birgit C Schlick-Steiner, Florian M Steiner
Accurate species delimitation is fundamental to biology. Traditionally, species were delimited based on morphological characters, sometimes leading to taxonomic uncertainty in morphologically conserved taxa. Recently, multiple taxonomically challenging cases have benefited from integrative taxonomy-an approach that highlights congruence among different disciplines and invokes evolutionary explanations for incongruence, acknowledging that different methods can mirror different stages of the speciation continuum...
February 11, 2016: Systematic Biology
Amanda D Melin, Donald W Kline, Chihiro Hiramatsu, Tim Caro
The century-old idea that stripes make zebras cryptic to large carnivores has never been examined systematically. We evaluated this hypothesis by passing digital images of zebras through species-specific spatial and colour filters to simulate their appearance for the visual systems of zebras' primary predators and zebras themselves. We also measured stripe widths and luminance contrast to estimate the maximum distances from which lions, spotted hyaenas, and zebras can resolve stripes. We found that beyond ca...
2016: PloS One
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