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Carlson ML, Stoddard MC. Evolution of Plumage Patterns in a Pattern Morphospace: A Phylogenetic Analysis of Melanerpine Woodpeckers. Am Nat 2024; 203:55-72. [PMID: 38207134 DOI: 10.1086/727508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
AbstractPlumage patterns of melanerpine (Melanerpes-Sphyrapicus) woodpeckers are strikingly diverse. Understanding the evolution and function of this diversity is challenging because of the difficulty of quantifying plumage patterns. We use a three-dimensional space to characterize the evolution of melanerpine achromatic plumage patterns. The axes of the space are three pattern features (spatial frequency, orientation, and contrast) quantified using two-dimensional fast Fourier transformation of museum specimen images. Mapping plumage in pattern space reveals differences in how species and subclades occupy the space. To quantify these differences, we derive two new measures of pattern: pattern diversity (diversity across plumage patches within a species) and pattern uniqueness (divergence of patterns from those of other species). We estimate that the melanerpine ancestor had mottled plumage and find that pattern traits across patches and subclades evolve at different rates. We also find that smaller species are more likely to display horizontal face patterning. We promote pattern spaces as powerful tools for investigating animal pattern evolution.
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Recknagel H, Harvey WT, Layton M, Elmer KR. Common lizard microhabitat selection varies by sex, parity mode, and colouration. BMC Ecol Evol 2023; 23:47. [PMID: 37667183 PMCID: PMC10478496 DOI: 10.1186/s12862-023-02158-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 08/22/2023] [Indexed: 09/06/2023] Open
Abstract
BACKGROUND Animals select and interact with their environment in various ways, including to ensure their physiology is at its optimal capacity, access to prey is possible, and predators can be avoided. Often conflicting, the balance of choices made may vary depending on an individual's life-history and condition. The common lizard (Zootoca vivipara) has egg-laying and live-bearing lineages and displays a variety of dorsal patterns and colouration. How colouration and reproductive mode affect habitat selection decisions on the landscape is not known. In this study, we first tested if co-occurring male and female viviparous and oviparous common lizards differ in their microhabitat selection. Second, we tested if the dorsal colouration of an individual lizard matched its basking site choice within the microhabitat where it was encountered, which could be related to camouflage and crypsis. RESULTS We found that site use differed from the habitat otherwise available, suggesting lizards actively choose the composition and structure of their microhabitat. Females were found in areas with more wood and less bare ground compared to males; we speculate that this may be for better camouflage and reducing predation risk during pregnancy, when females are less mobile. Microhabitat use also differed by parity mode: viviparous lizards were found in areas with more density of flowering plants, while oviparous lizards were found in areas that were wetter and had more moss. This may relate to differing habitat preferences of viviparous vs. oviparous for clutch lay sites. We found that an individual's dorsal colouration matched that of the substrate of its basking site. This could indicate that individuals may choose their basking site to optimise camouflage within microhabitat. Further, all individuals were found basking in areas close to cover, which we expect could be used to escape predation. CONCLUSIONS Our study suggests that common lizards may actively choose their microhabitat and basking site, balancing physiological requirements, escape response and camouflage as a tactic for predator avoidance. This varies for parity modes, sexes, and dorsal colourations, suggesting that individual optimisation strategies are influenced by inter-individual variation within populations as well as determined by evolutionary differences associated with life history.
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Affiliation(s)
- Hans Recknagel
- School of Biodiversity, One Health & Veterinary Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
- Biotechnical Faculty, Department of Biology, University of Ljubljana, 1000, Ljubljana, Slovenia
| | - William T Harvey
- School of Biodiversity, One Health & Veterinary Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
- Roslin Institute, University of Edinburgh, Edinburgh, UK
| | - Megan Layton
- School of Biodiversity, One Health & Veterinary Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Kathryn R Elmer
- School of Biodiversity, One Health & Veterinary Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK.
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3
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Wasserlauf Y, Gancz A, Ben Dov A, Efrat R, Sapir N, Dor R, Spiegel O. A telemetry study shows that an endangered nocturnal avian species roosts in extremely dry habitats to avoid predation. Sci Rep 2023; 13:11888. [PMID: 37482541 PMCID: PMC10363541 DOI: 10.1038/s41598-023-38981-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 07/18/2023] [Indexed: 07/25/2023] Open
Abstract
Describing animal space use is essential for understanding their ecological needs and for planning effective conservation schemes. Notably, certain biomes and life histories are understudied due to methodological challenges in tracking animals in their natural habitats. Specifically, both arid environments and nocturnal species are not sufficiently researched compared to diurnal species and to other biomes. This knowledge gap hinders our ability to properly prioritize habitats for species protection in areas undergoing human-related development. Here, we investigate the movement ecology of the Egyptian Nightjar (Caprimulgus aegyptius) in the arid Dead-sea region of Israel, the Palestinian Authority (the West Bank) and Jordan. This nocturnal insectivore is a cryptic desert-dweller and was considered locally extinct until it was rediscovered in 2016. For this work we tracked twelve individuals using GPS tags to determine how this resource-poor environment affects their home range, (predicting large areas), habitat use, and day-roost ecology. We found that the tracked Egyptian Nightjars had a much larger home range area than other Nightjar species, commuting nightly between foraging grounds and day-roosts. We found, as expected, intensive foraging activity at agricultural fields, where artificial irrigation likely supports higher resource (insect) density. Additionally, we found that individuals showed very high roosting site fidelity, often returning to the same specific site, located in extremely dry and exposed habitats, presumably for predator avoidance. This finding highlights the ecological value of these barren habitats that are often considered "lifeless" and therefore of lower priority for conservation. Consequently, our research demonstrates the importance of describing the space-use of nocturnal animals in arid habitats for conservation efforts.
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Affiliation(s)
- Yohay Wasserlauf
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, 6997801, Tel-Aviv, Israel.
| | - Ady Gancz
- The Exotic Clinic, 9978600, Gezer, Israel
| | | | - Ron Efrat
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 8499000, Midreshet Ben-Gurion, Israel
| | - Nir Sapir
- Department of Evolutionary and Environmental Biology and Institute of Evolution, University of Haifa, Haifa, Israel
| | - Roi Dor
- Department of Natural Sciences, The Open University of Israel, Ra'anana, Israel
| | - Orr Spiegel
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, 6997801, Tel-Aviv, Israel
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4
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Dunning J, Patil A, D'Alba L, Bond AL, Debruyn G, Dhinojwala A, Shawkey M, Jenni L. How woodcocks produce the most brilliant white plumage patches among the birds. J R Soc Interface 2023; 20:20220920. [PMID: 36854381 PMCID: PMC9974297 DOI: 10.1098/rsif.2022.0920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023] Open
Abstract
Until recently, and when compared with diurnal birds that use contrasting plumage patches and complex feather structures to convey visual information, communication in nocturnal and crepuscular species was considered to follow acoustic and chemical channels. However, many birds that are active in low-light environments have evolved intensely white plumage patches within otherwise inconspicuous plumages. We used spectrophotometry, electron microscopy, and optical modelling to explain the mechanisms producing bright white tail feather tips of the Eurasian woodcock Scolopax rusticola. Their diffuse reflectance was approximately 30% higher than any previously measured feather. This intense reflectance is the result of incoherent light scattering from a disordered nanostructure composed of keratin and air within the barb rami. In addition, the flattening, thickening and arrangement of those barbs create a Venetian-blind-like macrostructure that enhances the surface area for light reflection. We suggest that the woodcocks have evolved these bright white feather patches for long-range visual communication in dimly lit environments.
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Affiliation(s)
- Jamie Dunning
- Department of Life Sciences, Imperial College London, London, UK
| | - Anvay Patil
- School of Polymer Science and Polymer Engineering, The University of Akron, Akron, OH, USA,CertainTeed LLC, Malvern, PA, USA
| | - Liliana D'Alba
- Department of Biology, Evolution and Optics of Nanostructure Group, University of Ghent, Gent 9000, Belgium,Naturalis Biodiversity Center, Leiden, The Netherlands
| | | | - Gerben Debruyn
- Department of Biology, Evolution and Optics of Nanostructure Group, University of Ghent, Gent 9000, Belgium
| | - Ali Dhinojwala
- School of Polymer Science and Polymer Engineering, The University of Akron, Akron, OH, USA
| | - Matthew Shawkey
- Department of Biology, Evolution and Optics of Nanostructure Group, University of Ghent, Gent 9000, Belgium
| | - Lukas Jenni
- Swiss Ornithological Institute, Sempach, Switzerland
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5
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Jolkkonen J, Gaston KJ, Troscianko J. Artificial lighting affects the landscape of fear in a widely distributed shorebird. Commun Biol 2023; 6:131. [PMID: 36721045 PMCID: PMC9889372 DOI: 10.1038/s42003-023-04486-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 01/16/2023] [Indexed: 02/02/2023] Open
Abstract
Fear influences almost all aspects of a prey species' behaviour, such as its foraging and movement, and has the potential to cause trophic cascades. The superior low-light vision of many predators means that perceived predation risk in prey is likely to be affected by light levels. The widespread and increasing intensity of artificial light at night is therefore likely to interfere with this nocturnal visual arms race with unknown behavioural and ecological consequences. Here we test how the fear of predation perceived by wintering Eurasian curlew foraging on tidal flats is influenced by lighting. We quantified flight initiation distance (FID) of individuals under varying levels of natural and artificial illumination. Our results demonstrate that FID is significantly and substantially reduced at low light levels and increases under higher intensity illumination, with artificial light sources having a greater influence than natural sources. Contrary to the sensory-limitation hypothesis, the curlews' unwillingness to take flight in low-light appears to reflect the risks posed by low-light flight, and a desire to remain on valuable foraging grounds. These findings demonstrate how artificial light can shape the landscape of fear, and how this interacts with optimal foraging decisions, and the costs of taking flight.
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Affiliation(s)
- Juho Jolkkonen
- grid.9681.60000 0001 1013 7965Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Kevin J. Gaston
- grid.8391.30000 0004 1936 8024Environment & Sustainability Institute, University of Exeter, Penryn Campus, Penryn, Cornwall UK
| | - Jolyon Troscianko
- Centre for Ecology & Conservation, University of Exeter, Penryn Campus, Penryn, Cornwall, UK.
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Mark CJ, O'Hanlon JC, Holwell GI. Camouflage in lichen moths: Field predation experiments and avian vision modelling demonstrate the importance of wing pattern elements and background for survival. J Anim Ecol 2022; 91:2358-2369. [PMID: 36169598 PMCID: PMC10092008 DOI: 10.1111/1365-2656.13817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 09/15/2022] [Indexed: 12/15/2022]
Abstract
Background matching is perhaps the most ubiquitous form of defensive camouflage in the animal kingdom, an adaptive strategy that relies on the visual resemblance between a prey organism and its background to promote concealment from predators. The importance of background matching has been acknowledged for over a century, yet despite its renown and apparent pervasiveness, few studies exist that have objectively quantified its occurrence and tested the functional significance of background matching in a specific animal study system. The North Island lichen moth Declana atronivea presents a fascinating system to investigate such anti-predator coloration. This species possesses high contrast black and white forewings that appear to resemble lichen. Here we assessed the contribution of background matching to the antipredator defence of D. atronivea using field predation experiments with realistic models. We found that D. atronivea coloration confers a significant survival advantage against native avian predators when on lichen backgrounds compared to bark backgrounds, with an intermediate level of predation occurring when models were near, but not on lichen. This suggests that D. atronivea wing patterns are an adaptation for background matching. We subsequently used calibrated digital photography, avian vision modelling and image analysis techniques to objectively quantify the degree of background matching exhibited by D. atronivea and assessed the contribution of different visual elements (colour, luminance and pattern) to camouflage in this species. Only the pattern elements of D. atronivea presented a close match to that of the lichen backgrounds, with both chromatic and achromatic cues found to be poor predictors of background matching in this species. This study is one of the first to integrate vision modelling, quantitative image analysis and field predation experiments using realistic models to objectively quantify the level and functional significance of background matching in a real species, and presents an ideal system for further investigating the interrelation between multiple mechanisms of camouflage.
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Affiliation(s)
- Cassandra J Mark
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | - James C O'Hanlon
- School of Science and Technology, University of New England, Armidale, New South Wales, Australia
| | - Gregory I Holwell
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
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7
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Spatial differentiation of background matching strategies along a Late Pleistocene range expansion route. Evol Ecol 2022. [DOI: 10.1007/s10682-022-10216-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Tkaczyk SP, Chivers D, Wiebe K. Nest defense by Mountain Bluebirds (Sialia currucoides) is related to their sex and brood characteristics but not morphological attributes. CAN J ZOOL 2022. [DOI: 10.1139/cjz-2022-0064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Within species, bird parents defend their nests with different levels of intensity. Previous studies have examined several hypotheses for this variation by looking at factors such as morphological characteristics of the parents and the characteristics of the brood, but few have controlled for multiple factors simultaneously. Here we examined a broad range of factors that may influence the nest defense behaviour of Mountain Bluebirds (Sialia currucoides Bechstein, 1798), including the adult’s morphology (sex, age, plumage colour, body size, and body condition) and characteristics of their brood (size, hatch date, stage of nestling development). Parental aggression was triggered using a taxidermy mount of an American red squirrel (Tamiasciurus hudsonicus Erxleben, 1777). We found no relationship between nest defense and any morphological characteristic of adults but the intensity of nest defense was positively correlated with the stage of offspring development, clutch size, and hatch date consistent with parental investment theory. Males also defended nests more strongly than females, consistent with the premise of the renesting hypothesis that males have fewer future opportunities to breed and therefore are more invested in the current brood. Our results provide strong support for parental investment theory and renesting as the primary drivers of nest defense intensity in breeding birds.
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Affiliation(s)
- Simon P. Tkaczyk
- University of Saskatchewan, Department of Biology, Saskatoon, Canada
| | - D.P. Chivers
- Department of Biology, Saskatoon, Saskatchewan, Canada,
| | - Karen Wiebe
- University of Saskatchewan, Department of Biology, Saskatoon, Canada
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9
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de Alcantara Viana JV, Lourenço Garcia de Brito V, de Melo C. Colour matching by arthropods in burned and unburned backgrounds in a Neotropical savanna. AUSTRAL ECOL 2022. [DOI: 10.1111/aec.13225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- João Vitor de Alcantara Viana
- Programa de Pós‐Graduação em Ecologia e Conservação de Recursos Naturais, Laboratório de Ornitologia e Bioacústica Universidade Federal de Uberlândia (UFU) Uberlândia Brazil
- Programa de Pós‐Graduação em Ecologia, Laboratório de Interações Multitróficas e Biodiversidade, Instituto de Biologia Universidade Estadual de Campinas (UNICAMP) Campinas
- Laboratório de Interações Multitróficas e Biodiversidade Departamento de Biologia Animal, Instituto de Biologia Universidade Estadual de Campinas CP 6109, CEP 13083-970 Campinas São Paulo Brazil
| | | | - Celine de Melo
- Instituto de Biologia Universidade Federal de Uberlândia Uberlândia Brazil
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10
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Leveau LM, Ibáñez I. Nesting Site and Plumage Color Are the Main Traits Associated with Bird Species Presence in Urban Areas. Animals (Basel) 2022; 12:ani12091148. [PMID: 35565574 PMCID: PMC9099748 DOI: 10.3390/ani12091148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 04/22/2022] [Accepted: 04/26/2022] [Indexed: 02/04/2023] Open
Abstract
Simple Summary Urban areas are expected to grow in the next decades, filtering bird species from the regional pool based on their life history traits. The objective of this study is to determine different bird species responses to urbanization using ordination analysis, and to characterize their life history traits combining information about diet, habitat and plumage color. Species identified as ‘urban exploiters’ tended to nest in buildings and with uniform plumage, whereas those identified as ‘urban avoiders’ tended to be ground nesting species with variable plumage. A third type, ‘urban adapters’, tended to be tree-nesting species with a low diet breadth, intermediate plumage lightness, low presence of plumage sexual dimorphism and high presence of iridescence. The results suggest that nest predation and habitat loss may exclude ground nesting birds from urban areas. The high density of pedestrians in urban centers may favor uniform plumages in birds that enhance camouflage. Abstract Urban areas are expected to grow in the next decades, filtering bird species from the regional pool based on their life history traits. Although the impact of urbanization on traits such as diet, habitat and migratory behavior has been analyzed, their joint role with other traits related to plumage color has not yet been analyzed. Urban characteristics such as impervious surfaces, human presence and pollutants may be related to dark and uniform plumages. The objective of this study is to determine different bird species responses to urbanization using ordination analysis, and to characterize their life history traits combining information about diet, habitat and plumage color. Birds were surveyed along urban–rural gradients located in three cities of central Argentina. Species associations with urban characteristics were assessed through principal component analysis. Two axes were obtained: the first related positively to urban exploiters and negatively to urban avoiders, and a second axis related negatively to urban adapters. The scores of each axis were related to species traits through phylogenetic generalized least squares models. Species identified as ‘urban exploiters’ tended to nest in buildings and have uniform plumage, whereas those identified as ‘urban avoiders’ tended to be ground-nesting species with variable plumage. A third type, ‘urban adapters’, tended to be tree-nesting species with a low diet breadth, intermediate plumage lightness, low presence of plumage sexual dimorphism and high presence of iridescence. The results suggest that nest predation and habitat loss may exclude ground nesting birds from urban areas. The high density of pedestrians and domestic animals, such as cats and dogs, in urban centers may favor uniform plumages in birds that enhance camouflage.
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11
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Heinze P, Dieker P, Rowland HM, Schielzeth H. Evidence for morph-specific substrate choice in a green-brown polymorphic grasshopper. Behav Ecol 2021; 33:17-26. [PMID: 35197804 PMCID: PMC8857936 DOI: 10.1093/beheco/arab133] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 08/11/2021] [Accepted: 11/02/2021] [Indexed: 11/14/2022] Open
Abstract
Abstract
Orthopteran insects are characterized by high variability in body coloration, in particular featuring a widespread green-brown color polymorphism. The mechanisms that contribute to the maintenance of this apparently balanced polymorphism are not yet understood. To investigate whether morph-dependent microhabitat choice might contribute to the continued coexistence of multiple morphs, we studied substrate choice in the meadow grasshopper Pseudochorthippus parallelus. The meadow grasshopper occurs in multiple discrete, genetically determined color morphs that range from uniform brown to uniform green. We tested whether three common morphs preferentially choose differently colored backgrounds in an experimental arena. We found that a preference for green backgrounds was most pronounced in uniform green morphs. If differential choices improve morph-specific performance in natural habitats via crypsis and/or thermoregulatory benefits, they could help to equalize fitness differences among color morphs and potentially produce frequency-dependent microhabitat competition, though difference appear too small to serve as the only explanation. We also measured the reflectance of the grasshoppers and backgrounds and used visual modeling to quantify the detectability of the different morphs to a range of potential predators. Multiple potential predators, including birds and spiders, are predicted to distinguish between morphs chromatically, while other species, possibly including grasshoppers themselves, will perceive only differences in brightness. Our study provides the first evidence that morph-specific microhabitat choice might be relevant to the maintenance of the green-brown polymorphisms in grasshoppers and shows that visual distinctness of color morphs varies between perceivers.
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Affiliation(s)
- Pauline Heinze
- Population Ecology Group, Institute of Ecology and Evolution, Friedrich Schiller University Jena, Dornburger Straße, Jena, Germany
| | - Petra Dieker
- Population Ecology Group, Institute of Ecology and Evolution, Friedrich Schiller University Jena, Dornburger Straße, Jena, Germany
| | - Hannah M Rowland
- Research Group Predators and Toxic Prey, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße, Jena, Germany
| | - Holger Schielzeth
- Population Ecology Group, Institute of Ecology and Evolution, Friedrich Schiller University Jena, Dornburger Straße, Jena, Germany
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12
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Barnett JB, Michalis C, Scott-Samuel NE, Cuthill IC. Colour pattern variation forms local background matching camouflage in a leaf-mimicking toad. J Evol Biol 2021; 34:1531-1540. [PMID: 34465010 DOI: 10.1111/jeb.13923] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/17/2021] [Accepted: 08/26/2021] [Indexed: 12/26/2022]
Abstract
Optimal camouflage can, in principle, be relatively easily achieved in simple, homogeneous, environments where backgrounds always have the same colour, brightness and patterning. Natural environments are, however, rarely homogenous, and species often find themselves viewed against varied backgrounds where the task of concealment is more challenging. One result of variable backgrounds is the evolution of intraspecific phenotypic variation which may either be generalized, with multiple similarly cryptic patterns, or specialized, with each discrete colour form maximizing concealment against a single component of the background. We investigated the role of phenotypic variation in a highly variable population of the Neotropical toad Rhinella margaritifera using visual modelling and a computer-based detection task. We found that phenotypic variation was not divided into discrete colour morphs, and all toads were well camouflaged against the forest floor. However, although the whole population may appear to consist of random samples from the background, the toads were a particularly close match to the leaf litter, suggesting that they masquerade as dead leaves, which are themselves variable. Furthermore, rather than each colour form being equally effective against a single background, each toad was specialized towards its own particular local surroundings, as suggested by a specialist strategy. Taken together, these data highlight the importance of background matching to a nominally masquerading species, as well as how habitat heterogeneity at multiple spatial scales may affect the evolution of camouflage and phenotypic variation.
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Affiliation(s)
- James B Barnett
- School of Biological Sciences, University of Bristol, Bristol, UK.,Redpath Museum, McGill University, Montreal, QC, Canada.,Department of Psychology, Neuroscience, & Behaviour, McMaster University, Hamilton, ON, Canada
| | | | | | - Innes C Cuthill
- School of Biological Sciences, University of Bristol, Bristol, UK
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13
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Briolat ES, Arenas LM, Hughes AE, Liggins E, Stevens M. Generalist camouflage can be more successful than microhabitat specialisation in natural environments. BMC Ecol Evol 2021; 21:151. [PMID: 34344323 PMCID: PMC8330473 DOI: 10.1186/s12862-021-01883-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 07/25/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Crypsis by background-matching is a critical form of anti-predator defence for animals exposed to visual predators, but achieving effective camouflage in patchy and variable natural environments is not straightforward. To cope with heterogeneous backgrounds, animals could either specialise on particular microhabitat patches, appearing cryptic in some areas but mismatching others, or adopt a compromise strategy, providing partial matching across different patch types. Existing studies have tested the effectiveness of compromise strategies in only a limited set of circumstances, primarily with small targets varying in pattern, and usually in screen-based tasks. Here, we measured the detection risk associated with different background-matching strategies for relatively large targets, with human observers searching for them in natural scenes, and focusing on colour. Model prey were designed to either 'specialise' on the colour of common microhabitat patches, or 'generalise' by matching the average colour of the whole visual scenes. RESULTS In both the field and an equivalent online computer-based search task, targets adopting the generalist strategy were more successful in evading detection than those matching microhabitat patches. This advantage occurred because, across all possible locations in these experiments, targets were typically viewed against a patchwork of different microhabitat areas; the putatively generalist targets were thus more similar on average to their various immediate surroundings than were the specialists. CONCLUSIONS Demonstrating close agreement between the results of field and online search experiments provides useful validation of online citizen science methods commonly used to test principles of camouflage, at least for human observers. In finding a survival benefit to matching the average colour of the visual scenes in our chosen environment, our results highlight the importance of relative scales in determining optimal camouflage strategies, and suggest how compromise coloration can succeed in nature.
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Affiliation(s)
| | - Lina María Arenas
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, TR10 9FE, Penryn, UK
| | - Anna E Hughes
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, TR10 9FE, Penryn, UK
- Department of Psychology, University of Essex, Wivenhoe House, CO4 3SQ, Colchester, UK
| | - Eric Liggins
- , QinetiQ, Cody Technology Park, Ively Road, Farnborough, GU14 0LX, Hampshire, UK
| | - Martin Stevens
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, TR10 9FE, Penryn, UK
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14
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Briolat ES, Gaston KJ, Bennie J, Rosenfeld EJ, Troscianko J. Artificial nighttime lighting impacts visual ecology links between flowers, pollinators and predators. Nat Commun 2021; 12:4163. [PMID: 34230463 PMCID: PMC8260664 DOI: 10.1038/s41467-021-24394-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 06/15/2021] [Indexed: 11/18/2022] Open
Abstract
The nighttime environment is being altered rapidly over large areas worldwide through introduction of artificial lighting, from streetlights and other sources. This is predicted to impact the visual ecology of many organisms, affecting both their intra- and interspecific interactions. Here, we show the effects of different artificial light sources on multiple aspects of hawkmoth visual ecology, including their perception of floral signals for pollination, the potential for intraspecific sexual signalling, and the effectiveness of their visual defences against avian predators. Light sources fall into three broad categories: some that prevent use of chromatic signals for these behaviours, others that more closely mimic natural lighting conditions, and, finally, types whose effects vary with light intensity and signal colour. We find that Phosphor Converted (PC) amber LED lighting – often suggested to be less harmful to nocturnal insects – falls into this third disruptive group, with unpredictable consequences for insect visual ecology depending on distance from the light source and the colour of the objects viewed. The diversity of impacts of artificial lighting on hawkmoth visual ecology alone argues for a nuanced approach to outdoor lighting in environmentally sensitive areas, employing intensities and spectra designed to limit those effects of most significant concern. Artificial light at night is a major way in which humans are altering the environment, impacting the ecology and behaviour of other species. Modelling how nocturnal hawkmoths see and are seen under multiple light sources suggests a range of potentially disruptive impacts on key behaviours.
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Affiliation(s)
| | - Kevin J Gaston
- Environment & Sustainability Institute, University of Exeter, Penryn, UK
| | - Jonathan Bennie
- Environment & Sustainability Institute, University of Exeter, Penryn, UK
| | - Emma J Rosenfeld
- Environment & Sustainability Institute, University of Exeter, Penryn, UK
| | - Jolyon Troscianko
- Centre for Ecology & Conservation, University of Exeter, Penryn, UK.
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15
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Rohr VA, Volkmer T, Metzler D, Küpper C. Neoptile feathers contribute to outline concealment of precocial chicks. Sci Rep 2021; 11:5483. [PMID: 33750790 PMCID: PMC7943783 DOI: 10.1038/s41598-021-84227-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 02/12/2021] [Indexed: 11/22/2022] Open
Abstract
Camouflage is a widespread strategy to increase survival. The cryptic plumage colouration of precocial chicks improves camouflage often through disruptive colouration. Here, we examine whether and how fringed neoptile feathers conceal the outline of chicks. We first conducted a digital experiment to test two potential mechanisms for outline concealment through appendages: (1) reduction of edge intensity and (2) luminance transition. Local Edge Intensity Analysis showed that appendages decreased edge intensity whereas a mean luminance comparison revealed that the appendages created an intermediate transition zone to conceal the object's outline. For edge intensity, the outline diffusion was strongest for a vision system with low spatial acuity, which is characteristic of many mammalian chick predators. We then analysed photographs of young snowy plover (Charadrius nivosus) chicks to examine whether feathers increase outline concealment in a natural setting. Consistent with better camouflage, the outline of digitally cropped chicks with protruding feathers showed lower edge intensities than the outline of chicks without those feathers. However, the observed mean luminance changes did not indicate better concealment. Taken together, our results suggest that thin skin appendages such as neoptile feathers improve camouflage. As skin appendages are widespread, this mechanism may apply to many organisms.
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Affiliation(s)
- Veronika A Rohr
- Research Group for Behavioural Genetics and Evolutionary Ecology, Max Planck Institute for Ornithology, Seewiesen, Germany.
- Division of Evolutionary Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany.
| | - Tamara Volkmer
- Department of Migration, Max Planck Institute of Animal Behavior, Radolfzell, Germany
| | - Dirk Metzler
- Division of Evolutionary Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Clemens Küpper
- Research Group for Behavioural Genetics and Evolutionary Ecology, Max Planck Institute for Ornithology, Seewiesen, Germany.
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16
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Rowland HM, Burriss RP, Skelhorn J. The antipredator benefits of postural camouflage in peppered moth caterpillars. Sci Rep 2020; 10:21654. [PMID: 33303853 PMCID: PMC7728781 DOI: 10.1038/s41598-020-78686-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 11/27/2020] [Indexed: 11/09/2022] Open
Abstract
Camouflage is the most common form of antipredator defense, and is a textbook example of natural selection. How animals’ appearances prevent detection or recognition is well studied, but the role of prey behavior has received much less attention. Here we report a series of experiments with twig-mimicking larvae of the American peppered moth Biston betularia that test the long-held view that prey have evolved postures that enhance their camouflage, and establish how food availability and ambient temperature affect these postures. We found that predators took longer to attack larvae that were resting in a twig-like posture than larvae resting flat against a branch. Larvae that were chilled or food restricted (manipulations intended to energetically stress larvae) adopted a less twig-like posture than larvae that were fed ad libitum. Our findings provide clear evidence that animals gain antipredator benefits from postural camouflage, and suggest that benefits may come at an energetic cost that animals are unwilling or unable to pay under some conditions.
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Affiliation(s)
- Hannah M Rowland
- Max Planck Research Group Predators and Toxic Prey, Max Planck Institute for Chemical Ecology, Hans Knӧll Straβe 8, 07745, Jena, Germany. .,Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK.
| | - Robert P Burriss
- Department of Psychology, The University of Basel, Missionsstrasse 62, 4055, Basel, Switzerland
| | - John Skelhorn
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Henry Wellcome Building, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
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17
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Biagolini-Jr C, Perrella DF. Bright coloration of male blue manakin is not connected to higher rates of nest predation. Acta Ethol 2020. [DOI: 10.1007/s10211-020-00352-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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18
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Zonana DM, Gee JM, Breed MD, Doak DF. Dynamic shifts in social network structure and composition within a breeding hybrid population. J Anim Ecol 2020; 90:197-211. [PMID: 32772372 DOI: 10.1111/1365-2656.13314] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 06/24/2020] [Indexed: 01/21/2023]
Abstract
Mating behaviour and the timing of reproduction can inhibit genetic exchange between closely related species; however, these reproductive barriers are challenging to measure within natural populations. Social network analysis provides promising tools for studying the social context of hybridization, and the exchange of genetic variation, more generally. We test how social networks within a hybrid population of California Callipepla californica and Gambel's quail Callipepla gambelii change over discrete periods of a breeding season. We assess patterns of phenotypic and genotypic assortment, and ask whether altered associations between individuals (association rewiring), or changes to the composition of the population (individual turnover) drive network dynamics. We use genetic data to test whether social associations and relatedness between individuals correlate with patterns of parentage within the hybrid population. To achieve these aims, we combine RFID association data, phenotypic data and genomic measures with social network analyses. We adopt methods from the ecological network literature to quantify shifts in network structure and to partition changes into those due to individual turnover and association rewiring. We integrate genomic data into networks as node-level attributes (ancestry) and edges (relatedness, parentage) to test links between social and parentage networks. We show that rewiring of associations between individuals that persist across network periods, rather than individual turnover, drives the majority of the changes in network structure throughout the breeding season, and that the traits involved in phenotypic/genotypic assortment were highly dynamic over time. Social networks were randomly assorted based on genetic ancestry, suggesting weak behavioural reproductive isolation within this hybrid population. Finally, we show that the strength of associations within the social network, but not levels of genetic relatedness, predicts patterns of parentage. Social networks play an important role in population processes such as the transmission of disease and information, yet there has been less focus on how networks influence the exchange of genetic variation. By integrating analyses of social structure, phenotypic assortment and reproductive outcomes within a hybrid zone, we demonstrate the utility of social networks for analysing links between social context and gene flow within wild populations.
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Affiliation(s)
- David M Zonana
- Department of Ecology & Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Jennifer M Gee
- James San Jacinto Mountains Reserve, University of California - Riverside, University of California Natural Reserve System, Idyllwild, CA, USA
| | - Michael D Breed
- Department of Ecology & Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Daniel F Doak
- Environmental Studies Program, University of Colorado, Boulder, CO, USA
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19
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Peach K, Liu JW, Mazer SJ. Climate Predicts UV Floral Pattern Size, Anthocyanin Concentration, and Pollen Performance in Clarkia unguiculata. FRONTIERS IN PLANT SCIENCE 2020; 11:847. [PMID: 32612627 PMCID: PMC7308548 DOI: 10.3389/fpls.2020.00847] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 05/26/2020] [Indexed: 05/25/2023]
Abstract
Given that flower size and pigmentation can mediate plant-pollinator interactions, many studies have focused on pollinator-driven selection on these floral traits. However, abiotic factors such as precipitation, temperature, and solar radiation also contribute to geographic variation in floral color, pattern, and size within multiple species. Several studies have described an ecogeographic pattern within species in which high temperature, high ultraviolet (UV) radiation, low precipitation and/or low latitudes are associated with increased floral anthocyanin production, smaller flowers, and/or larger UV-absorbing floral patterns (nectar guides or bullseyes). However, latitude or elevation is often used as a proxy variable to study variation in floral traits associated with a wide range of climatic variables, making the proximate abiotic drivers of variation difficult to identify. In this study, we tested and corroborated several predictions for how the abiotic environment may directly or indirectly shape geographic patterns of floral color, pattern, and size in Clarkia unguiculata (Onagraceae). This study provides the first report of geographic variation in multispectral floral color and pattern in C. unguiculata, while also providing an experimental test of the putative protective role of UV absorption for pollen performance. We quantified geographic variation among greenhouse-raised populations in UV floral pattern size, mean UV petal reflectance, anthocyanin concentration, and petal area in C. unguiculata across its natural range in California and, using 30 year climate normals for each population, we identified climatic and topographic attributes that are correlated with our focal floral traits. In addition, we examined pollen performance under high and low UV light conditions to detect the protective function (if any) of UV floral patterns in this species. Contrary to our expectations, the nectar guide and the proportion of the petal occupied by the UV nectar guide were largest in low solar UV populations. Estimated floral anthocyanin concentration was highest in populations with high solar UV, which does support our predictions. The size of the UV nectar guide did not affect pollen performance in either of the light treatments used in this study. We conclude that, under the conditions examined here, UV-absorbing floral patterns do not serve a direct "pollen protection" function in C. unguiculata. Our results only partially align with expected ecogeographic patterns in these floral traits, highlighting the need for research in a wider range of taxa in order to detect and interpret broad scale patterns of floral color variation.
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Affiliation(s)
- Kristen Peach
- Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Jasen W. Liu
- Population Biology Graduate Group, University of California, Davis, Davis, CA, United States
| | - Susan J. Mazer
- Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, United States
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20
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Camacho C, Sanabria-Fernández A, Baños-Villalba A, Edelaar P. Experimental evidence that matching habitat choice drives local adaptation in a wild population. Proc Biol Sci 2020; 287:20200721. [PMID: 32429813 PMCID: PMC7287376 DOI: 10.1098/rspb.2020.0721] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 04/23/2020] [Indexed: 12/11/2022] Open
Abstract
Matching habitat choice is a unique, flexible form of habitat choice based on self-assessment of local performance. This mechanism is thought to play an important role in adaptation and population persistence in variable environments. Nevertheless, the operation of matching habitat choice in natural populations remains to be unequivocally demonstrated. We investigated the association between body colour and substrate use by ground-perching grasshoppers (Sphingonotus azurescens) in an urban mosaic of dark and pale pavements, and then performed a colour manipulation experiment to test for matching habitat choice based on camouflage through background matching. Naturally, dark and pale grasshoppers occurred mostly on pavements that provided matching backgrounds. Colour-manipulated individuals recapitulated this pattern, such that black-painted and white-painted grasshoppers recaptured after the treatment aggregated together on the dark asphalt and pale pavement, respectively. Our study demonstrates that grasshoppers adjust their movement patterns to choose the substrate that confers an apparent improvement in camouflage given their individual-specific colour. More generally, our study provides unique experimental evidence of matching habitat choice as a driver of phenotype-environment correlations in natural populations and, furthermore, suggests that performance-based habitat choice might act as a mechanism of adaptation to changing environments, including human-modified (urban) landscapes.
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Affiliation(s)
| | | | | | - Pim Edelaar
- Department of Molecular Biology and Biochemical Engineering, University Pablo de Olavide, Carretera Utrera km. 1, 41013 Seville, Spain
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21
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Galloway JAM, Green SD, Stevens M, Kelley LA. Finding a signal hidden among noise: how can predators overcome camouflage strategies? Philos Trans R Soc Lond B Biol Sci 2020; 375:20190478. [PMID: 32420842 PMCID: PMC7331011 DOI: 10.1098/rstb.2019.0478] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Substantial progress has been made in the past 15 years regarding how prey use a variety of visual camouflage types to exploit both predator visual processing and cognition, including background matching, disruptive coloration, countershading and masquerade. By contrast, much less attention has been paid to how predators might overcome these defences. Such strategies include the evolution of more acute senses, the co-opting of other senses not targeted by camouflage, changes in cognition such as forming search images, and using behaviours that change the relationship between the cryptic individual and the environment or disturb prey and cause movement. Here, we evaluate the methods through which visual camouflage prevents detection and recognition, and discuss if and how predators might evolve, develop or learn counter-adaptations to overcome these. This article is part of the theme issue ‘Signal detection theory in recognition systems: from evolving models to experimental tests'.
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Affiliation(s)
- James A M Galloway
- Centre for Ecology and Conservation, University of Exeter (Penryn Campus), Cornwall TR10 9FE, UK
| | - Samuel D Green
- Centre for Ecology and Conservation, University of Exeter (Penryn Campus), Cornwall TR10 9FE, UK
| | - Martin Stevens
- Centre for Ecology and Conservation, University of Exeter (Penryn Campus), Cornwall TR10 9FE, UK
| | - Laura A Kelley
- Centre for Ecology and Conservation, University of Exeter (Penryn Campus), Cornwall TR10 9FE, UK
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22
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Nokelainen O, Brito JC, Scott-Samuel NE, Valkonen JK, Boratyński Z. Camouflage accuracy in Sahara-Sahel desert rodents. J Anim Ecol 2020; 89:1658-1669. [PMID: 32227336 DOI: 10.1111/1365-2656.13225] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 01/31/2020] [Indexed: 01/21/2023]
Abstract
Camouflage helps animals to hide from predators and is therefore key to survival. Although widespread convergence of animal phenotypes to their natural environment is well-established, there is a lack of knowledge about how species compromise camouflage accuracy across different background types in their habitat. Here we tested how background matching has responded to top-down selection by avian and mammalian predators using Sahara-Sahel desert rodents in North Africa. We show that the fur colouration of several species has become an accurate match to different types of desert habitats. This is supported by a correlation analysis of colour and pattern metrics, investigation of animal-to-background similarities at different spatial scales and is confirmed by modelling of two predator vision systems. The background match was closest across large (or global) spatial scales, suggesting a generalist camouflage tactic for many background types. Some species, may have a better match to the background over small (or focal) spatial scales, which could be the result of habitat choices or differential predation. Nevertheless, predicted discrimination distances of fur colouration were virtually indistinguishable for mammalian and low for avian vision model, which implies effective camouflage. Our study provides one of the best documented cases of multilevel camouflage accuracy in geographically widespread taxa. We conclude that background matching has become an effective and common adaptation against predatory threat in Sahara-Sahelian desert rodents.
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Affiliation(s)
- Ossi Nokelainen
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - José Carlos Brito
- CIBIO-InBIO Associate Laboratory, Research Center in Biodiversity and Genetic Resources, University of Porto, Porto, Portugal
| | | | - Janne K Valkonen
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Zbyszek Boratyński
- CIBIO-InBIO Associate Laboratory, Research Center in Biodiversity and Genetic Resources, University of Porto, Porto, Portugal
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23
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da Silva CRB, van den Berg CP, Condon ND, Riginos C, Wilson RS, Cheney KL. Intertidal gobies acclimate rate of luminance change for background matching with shifts in seasonal temperature. J Anim Ecol 2020; 89:1735-1746. [PMID: 32227334 DOI: 10.1111/1365-2656.13226] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 03/10/2020] [Indexed: 11/29/2022]
Abstract
Rate of colour change and background matching capacity are important functional traits for avoiding predation and hiding from prey. Acute changes in environmental temperature are known to impact the rate at which animals change colour, and therefore may affect their survival. Many ectotherms have the ability to acclimate performance traits such as locomotion, metabolic rate and growth rate with changes in seasonal temperature. However, it remains unclear how other functional traits that are directly linked to behaviour and survival respond to long-term changes in temperature (within an individual's lifetime). We assessed whether the rate of colour change is altered by long-term changes in temperature (seasonal variation) and if rate of colour change can acclimate to seasonal thermal conditions. We used an intertidal rock-pool goby Bathygobius cocosensis, to test this and exposed individuals to representative seasonal mean temperatures (16 or 31°C, herein referred to cold- and warm-exposed fish respectively) for 9 weeks and then tested their rate of luminance change when placed on white and black backgrounds at acute test temperatures 16 and 31°C. We modelled rate of luminance change using the visual sensitives of a coral trout Plectropmus leopardus to determine how well gobies matched their backgrounds in terms of luminance contrast to a potential predator. After exposure to long-term seasonal conditions, the warm-exposed fish had faster rates of luminance change and matched their background more closely when tested at 31 than at 16°C. Similarly, the cold-exposed fish had faster rates of luminance change and matched their backgrounds more closely at 16°C than at 31°C. This demonstrates that rate of luminance change can be adjusted to compensate for long-term changes in seasonal temperature. This is the first study to show that animals can acclimate rate of colour change for background matching to seasonal thermal conditions. We also show that rapid changes in acute temperature reduce background matching capabilities. Stochastic changes in climate are likely to affect the frequency of predator-prey interactions which may have substantial knock-on effects throughout ecosystems.
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Affiliation(s)
- Carmen R B da Silva
- School of Biological Sciences, The University of Queensland, St Lucia, QLD, Australia.,School of Biological Sciences, Monash University, Clayton, Vic., Australia
| | - Cedric P van den Berg
- School of Biological Sciences, The University of Queensland, St Lucia, QLD, Australia
| | - Nicholas D Condon
- Institute for Molecular Biosciences, The University of Queensland, St Lucia, QLD, Australia
| | - Cynthia Riginos
- School of Biological Sciences, The University of Queensland, St Lucia, QLD, Australia
| | - Robbie S Wilson
- School of Biological Sciences, The University of Queensland, St Lucia, QLD, Australia
| | - Karen L Cheney
- School of Biological Sciences, The University of Queensland, St Lucia, QLD, Australia.,Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
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24
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Edelaar P, Baños-Villalba A, Quevedo DP, Escudero G, Bolnick DI, Jordán-Andrade A. Biased movement drives local cryptic coloration on distinct urban pavements. Proc Biol Sci 2019; 286:20191343. [PMID: 31575366 DOI: 10.1098/rspb.2019.1343] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Explanations of how organisms might adapt to urban environments have mostly focused on divergent natural selection and adaptive plasticity. However, differential habitat choice has been suggested as an alternative. Here, we test for habitat choice in enhancing crypsis in ground-perching grasshoppers colonizing an urbanized environment, composed of a mosaic of four distinctly coloured substrates (asphalt roads and adjacent pavements). Additionally, we determine its relative importance compared to present-day natural selection and phenotypic plasticity. We found that grasshoppers are very mobile, but nevertheless approximately match the colour of their local substrate. By manipulating grasshopper colour, we confirm that grasshoppers increase the usage of those urban substrates that resemble their own colours. This selective movement actively improves crypsis. Colour divergence between grasshoppers on different substrates is not or hardly owing to present-day natural selection, because observed mortality rates are too low to counteract random substrate use. Additional experiments also show negligible contributions from plasticity in colour. Our results confirm that matching habitat choice can be an important driver of adaptation to urban environments. In general, studies should more fully incorporate that individuals are not only selective targets (i.e. selected on by the environment), but also selective agents (i.e. selecting their own environments).
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Affiliation(s)
- Pim Edelaar
- Department of Molecular Biology and Biochemical Engineering, University Pablo de Olavide, Carretera Utrera km.1, 41013 Seville, Spain
| | - Adrian Baños-Villalba
- Department of Molecular Biology and Biochemical Engineering, University Pablo de Olavide, Carretera Utrera km.1, 41013 Seville, Spain
| | - David P Quevedo
- Department of Molecular Biology and Biochemical Engineering, University Pablo de Olavide, Carretera Utrera km.1, 41013 Seville, Spain.,Department of Ethology and Biodiversity Conservation, Doñana Biological Station-Spanish Research Council (EBD-CSIC), Avenida Americo Vespucio 26, 41092 Seville, Spain
| | - Graciela Escudero
- Department of Molecular Biology and Biochemical Engineering, University Pablo de Olavide, Carretera Utrera km.1, 41013 Seville, Spain
| | - Daniel I Bolnick
- Department of Ecology and Evolutionary Biology, University of Connecticut, 75N. Eagleville Road, Storrs, CT 06269-3043, USA.,Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Aída Jordán-Andrade
- Department of Molecular Biology and Biochemical Engineering, University Pablo de Olavide, Carretera Utrera km.1, 41013 Seville, Spain
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25
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Saavedra I, Amo L. Egg concealment is an antipredatory strategy in a cavity‐nesting bird. Ethology 2019. [DOI: 10.1111/eth.12932] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Irene Saavedra
- Departamento de Ecología Evolutiva Museo Nacional de Ciencias Naturales (CSIC) Madrid Spain
| | - Luisa Amo
- Departamento de Ecología Evolutiva Museo Nacional de Ciencias Naturales (CSIC) Madrid Spain
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26
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Salisbury JW, Peters RA. Non-random perch selection by cryptic lizards, Amphibolurus muricatus. Behav Ecol Sociobiol 2019. [DOI: 10.1007/s00265-019-2730-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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27
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Pärssinen V, Kalb N, Vallon M, Anthes N, Heubel K. Male and female preferences for nest characteristics under paternal care. Ecol Evol 2019; 9:7780-7791. [PMID: 31346440 PMCID: PMC6635949 DOI: 10.1002/ece3.5363] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 05/13/2019] [Accepted: 05/17/2019] [Indexed: 01/11/2023] Open
Abstract
Nests play a critical role for offspring development across the animal kingdom. Nest quality may contribute to the builder's extended phenotype and serve as an ornament during mate choice. We examined male and female nest choice in the common goby (Pomatoschistus microps), a benthic fish with male-only parental care where females deposit eggs in male-built nests. Using prebuilt nest models, we independently manipulated two candidate nest quality traits: (a) nest entrance width with a role in oxygen ventilation, and (b) extent of sand cover with a role in camouflage. In simultaneous choice trials, male gobies exhibited no preference for any nest model type. This suggests that initial characteristics of a nesting substrate have minor importance for males, which usually remodel the nest. Females were given a choice between two males occupying either entrance- or cover-manipulated nests. The same pair of males was then exposed to a second female but now with alternated nest types assigned. Most females were consistent in choosing the same, typically the heavier male of the two regardless of nest properties. However, the females that chose the same nest regardless of the male preferred low over high sand coverage and narrow over wide nest entrance. Our results indicate that females base their mating decision on a combination of male phenotype and nest traits. While we found no indication that females are attracted to highly decorated nests, our study is the first in fishes to disentangle a preference for narrow (and thus more protective) nest entrances independent of nest coverage.
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Affiliation(s)
- Varpu Pärssinen
- Department of BiosciencesUniversity of HelsinkiHelsinkiFinland
- Tvärminne Zoological StationUniversity of HelsinkiHankoFinland
- Department of BiologyLund UniversityLundSweden
| | - Nadine Kalb
- Institute for Evolution and EcologyUniversity of TübingenTübingenGermany
- Department of BiologyUniversity of TübingenTübingenGermany
| | - Martin Vallon
- Institute for Evolution and EcologyUniversity of TübingenTübingenGermany
| | - Nils Anthes
- Institute for Evolution and EcologyUniversity of TübingenTübingenGermany
| | - Katja Heubel
- Department of BiosciencesUniversity of HelsinkiHelsinkiFinland
- Tvärminne Zoological StationUniversity of HelsinkiHankoFinland
- Institute for Evolution and EcologyUniversity of TübingenTübingenGermany
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28
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Green SD, Duarte RC, Kellett E, Alagaratnam N, Stevens M. Colour change and behavioural choice facilitate chameleon prawn camouflage against different seaweed backgrounds. Commun Biol 2019; 2:230. [PMID: 31263774 PMCID: PMC6588621 DOI: 10.1038/s42003-019-0465-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 05/20/2019] [Indexed: 12/17/2022] Open
Abstract
Camouflage is driven by matching the visual environment, yet natural habitats are rarely uniform and comprise many backgrounds. Therefore, species often exhibit adaptive traits to maintain crypsis, including colour change and behavioural choice of substrates. However, previous work largely considered these solutions in isolation, whereas many species may use a combination of behaviour and appearance to facilitate concealment. Here we show that green and red chameleon prawns (Hippolyte varians) closely resemble their associated seaweed substrates to the vision of predatory fish, and that they can change colour to effectively match new backgrounds. Prawns also select colour-matching substrates when offered a choice. However, colour change occurs over weeks, consistent with seasonal changes in algal cover, whereas behavioural choice of matching substrates occurs in the short-term, facilitating matches within heterogeneous environments. We demonstrate how colour change and behaviour combine to facilitate camouflage against different substrates in environments varying spatially and temporally.
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Affiliation(s)
- Samuel D. Green
- Centre for Ecology and Conservation, University of Exeter (Penryn Campus), Cornwall, TR10 9FE UK
| | - Rafael C. Duarte
- Centro de Biologia Marinha, Universidade de São Paulo, São Sebastião, 11612-109 Brazil
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC (UFABC), São Bernardo do Campo, 09606-045 Brazil
| | - Emily Kellett
- Centre for Ecology and Conservation, University of Exeter (Penryn Campus), Cornwall, TR10 9FE UK
| | - Natasha Alagaratnam
- Centre for Ecology and Conservation, University of Exeter (Penryn Campus), Cornwall, TR10 9FE UK
| | - Martin Stevens
- Centre for Ecology and Conservation, University of Exeter (Penryn Campus), Cornwall, TR10 9FE UK
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Moon RM, Kamath A. Re-examining escape behaviour and habitat use as correlates of dorsal pattern variation in female brown anole lizards,Anolis sagrei(Squamata: Dactyloidae). Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/blz006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Rachel M Moon
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Ambika Kamath
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
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Stevens M, Ruxton GD. The key role of behaviour in animal camouflage. Biol Rev Camb Philos Soc 2019; 94:116-134. [PMID: 29927061 PMCID: PMC6378595 DOI: 10.1111/brv.12438] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 05/25/2018] [Accepted: 05/31/2018] [Indexed: 01/24/2023]
Abstract
Animal camouflage represents one of the most important ways of preventing (or facilitating) predation. It attracted the attention of the earliest evolutionary biologists, and today remains a focus of investigation in areas ranging from evolutionary ecology, animal decision-making, optimal strategies, visual psychology, computer science, to materials science. Most work focuses on the role of animal morphology per se, and its interactions with the background in affecting detection and recognition. However, the behaviour of organisms is likely to be crucial in affecting camouflage too, through background choice, body orientation and positioning; and strategies of camouflage that require movement. A wealth of potential mechanisms may affect such behaviours, from imprinting and self-assessment to genetics, and operate at several levels (species, morph, and individual). Over many years there have been numerous studies investigating the role of behaviour in camouflage, but to date, no effort to synthesise these studies and ideas into a coherent framework. Here, we review key work on behaviour and camouflage, highlight the mechanisms involved and implications of behaviour, discuss the importance of this in a changing world, and offer suggestions for addressing the many important gaps in our understanding of this subject.
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Affiliation(s)
- Martin Stevens
- Centre for Ecology and Conservation, College of Life and Environmental SciencesUniversity of Exeter, Penryn CampusPenryn, TR10 9FEU.K.
| | - Graeme D. Ruxton
- School of BiologyUniversity of St AndrewsSt Andrews, KY16 9THU.K.
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Walton OC, Stevens M. Avian vision models and field experiments determine the survival value of peppered moth camouflage. Commun Biol 2018; 1:118. [PMID: 30271998 PMCID: PMC6123793 DOI: 10.1038/s42003-018-0126-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 07/25/2018] [Indexed: 11/14/2022] Open
Abstract
Animal defensive coloration has long provided many important examples of evolution and adaptation. Of these, industrial melanism in the peppered moth is the classic textbook example of evolution in action, whereby dark and pale morphs suffer differential predation in polluted and unpolluted woodland based on their camouflage. Despite extensive work, a striking gap remains in that no study has ever objectively quantified their camouflage or related this directly to predation risk. Here we use image analysis and avian vision models to show that pale individuals more closely match lichen backgrounds than dark morphs. Artificial predation experiments in unpolluted woodland show 21% higher survival rates of pale than melanic individuals. Overall, we provide the strongest direct evidence to date that peppered moth morph frequencies stem from differential camouflage and avian predation, providing key support for this iconic example of natural selection.
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Affiliation(s)
- Olivia C Walton
- Centre for Ecology & Conservation, College of Life & Environmental Sciences, University of Exeter, Penryn Campus, Penryn, Cornwall, TR10 9FE, UK
| | - Martin Stevens
- Centre for Ecology & Conservation, College of Life & Environmental Sciences, University of Exeter, Penryn Campus, Penryn, Cornwall, TR10 9FE, UK.
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Individual egg camouflage is influenced by microhabitat selection and use of nest materials in ground-nesting birds. Behav Ecol Sociobiol 2018. [DOI: 10.1007/s00265-018-2558-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Niu Y, Sun H, Stevens M. Plant Camouflage: Ecology, Evolution, and Implications. Trends Ecol Evol 2018; 33:608-618. [DOI: 10.1016/j.tree.2018.05.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 05/24/2018] [Accepted: 05/29/2018] [Indexed: 11/15/2022]
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