Search results for "Camouflage"
showing 10 items of 24 documents
Deimatism: a neglected component of antipredator defence
2017
Deimatic or ‘startle’ displays cause a receiver to recoil reflexively in response to a sudden change in sensory input. Deimatism is sometimes implicitly treated as a form of aposematism (unprofitability associated with a signal). However, the fundamental difference is, in order to provide protection, deimatism does not require a predator to have any learned or innate aversion. Instead, deimatism can confer a survival advantage by exploiting existing neural mechanisms in a way that releases a reflexive response in the predator. We discuss the differences among deimatism, aposematism, and forms of mimicry, and their ecological and evolutionary implications. We highlight outstanding questions …
Repeated evolution of camouflage in speciose desert rodents
2017
AbstractThere are two main factors explaining variation among species and the evolution of characters along phylogeny: adaptive change, including phenotypic and genetic responses to selective pressures, and phylogenetic inertia, or the resemblance between species due to shared phylogenetic history. Phenotype-habitat colour match, a classic Darwinian example of the evolution of camouflage (crypsis), offers the opportunity to test the importance of historical versus ecological mechanisms in shaping phenotypes among phylogenetically closely related taxa. To assess it, we investigated fur (phenotypic data) and habitat (remote sensing data) colourations, along with phylogenetic information, in t…
Through predators’ eyes: phenotype–environment associations in shore crab coloration at different spatial scales
2017
We thank Emil Aaltonen Foundation providing a young scientist grant for this research (O.N.). MS and AEL were supported by a Biotechnology and Biological Sciences Research Council (BBSRC) David Phillips Research Fellowship (BB/G022887/1).
Variable crab camouflage patterns defeat search image formation.
2021
Understanding what maintains the broad spectrum of variation in animal phenotypes and how this influences survival is a key question in biology. Frequency dependent selection – where predators temporarily focus on one morph at the expense of others by forming a “search image” – can help explain this phenomenon. However, past work has never tested real prey colour patterns, and rarely considered the role of different types of camouflage. Using a novel citizen science computer experiment that presented crab “prey” to humans against natural backgrounds in specific sequences, we were able to test a range of key hypotheses concerning the interactions between predator learning, camouflage and mor…
The current and future state of animal coloration research
2017
Animal colour patterns are a model system for understanding evolution because they are unusually accessible for study and experimental manipulation. This is possible because their functions are readily identifiable. In this final paper of the symposium we provide a diagram of the processes affecting colour patterns and use this to summarize their functions and put the other papers in a broad context. This allows us to identify significant ‘holes’ in the field that only become obvious when we see the processes affecting colour patterns, and their interactions, as a whole. We make suggestions about new directions of research that will enhance our understanding of both the evolution of colour …
Fight or flight trade-offs and the defensive behaviour of the mountain katydid, Acripeza reticulata
2020
The defensive repertoires of prey are shaped by diverse ecological and evolutionary demands. This can generate trade-offs between the components of defences, as in the classic ‘fight or flight’ dichotomy, or dedicated investment in a singular end, allowing individuals in better condition to mount a more effective defence all round. Further, sexual dimorphism may drive sex differences in such responses, although our understanding of the interaction between sexual selection and defensive behaviour is in its infancy. Deimatic, or ‘startle’, defences typically combine multiple protective strategies, such as camouflage and aposematism, with a rapid transition between them, and thus offer unique …
Warning coloration can be disruptive: aposematic marginal wing patterning in the wood tiger moth
2015
Warning (aposematic) and cryptic colorations appear to be mutually incompatible because the primary function of the former is to increase detectability, whereas the function of the latter is to decrease it. Disruptive coloration is a type of crypsis in which the color pattern breaks up the outline of the prey, thus hindering its detection. This delusion can work even when the prey’s pattern elements are highly contrasting; thus, it is possible for an animal’s coloration to combine both warning and disruptive functions. The coloration of the wood tiger moth (Parasemia plantaginis) is such that the moth is conspicuous when it rests on vegetation, but when it feigns death and drops to the gras…
Gray plumage color is more cryptic than brown in snowy landscapes in a resident color polymorphic bird
2020
Abstract Camouflage may promote fitness of given phenotypes in different environments. The tawny owl (Strix aluco) is a color polymorphic species with a gray and brown morph resident in the Western Palearctic. A strong selection pressure against the brown morph during snowy and cold winters has been documented earlier, but the selection mechanisms remain unresolved. Here, we hypothesize that selection favors the gray morph because it is better camouflaged against predators and mobbers in snowy conditions compared to the brown one. We conducted an online citizen science experiment where volunteers were asked to locate a gray or a brown tawny owl specimen from pictures taken in snowy and snow…
Specific color sensitivities of prey and predator explain camouflage in different visual systems
2004
In situations of aggressive mimicry, predators adapt their color to that of the substrate on which they sit for hunting, a behavior that is presumed to hide them from prey as well as from their own predators. Females of few crab-spider species encounter such situations when lying on flowers to ambush pollinators. To evaluate the efficiency of spider camouflage on flowers, we measured by spectroradiometry adult female Thomisus onustus and marguerite daisies, Leucanthemum vulgare. We compared chromatic contrast (color used for short-range detection) of each pair of spider and flower to detection thresholds computed in the visual systems of both Hymenopteran prey and passerine bird predator. W…
Camouflage accuracy in Sahara–Sahel desert rodents
2020
1. 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.2. 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.3. 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…