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The Edibility of Birds: Illustrated by Five Years' Experiments and Observations (1941–1946) on the Food Preferences of the Hornet, Cat and Man;and considered with Special Reference to the Theories of Adaptive Coloration

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... Many of the early critics of natural selection (Darwin 1859) argued that natural selection could not explain the evolution of showy phenotypes (such as peacock trains), given that they increase the likelihood of predation. Darwin (1871) expanded his initial outline of sexual selection to respond to these critics, and we now view showy plumage as a potential burden, and many investigators have noted that cryptic prey should be less vulnerable to visual hunting predators than conspicuous prey (Cott 1940;Merilata 1999;Merilata and Lind 2005). Indeed, much empirical work supports this claim (e.g., Götmark 1993;Stuart-Fox et al. 2003;), yet ornamented plumage could signal unpalatability (aposematism) or unprofitability to predators (Cott 1940(Cott , 1946Baker and Parker 1979;Guilford 1986). ...
... Darwin (1871) expanded his initial outline of sexual selection to respond to these critics, and we now view showy plumage as a potential burden, and many investigators have noted that cryptic prey should be less vulnerable to visual hunting predators than conspicuous prey (Cott 1940;Merilata 1999;Merilata and Lind 2005). Indeed, much empirical work supports this claim (e.g., Götmark 1993;Stuart-Fox et al. 2003;), yet ornamented plumage could signal unpalatability (aposematism) or unprofitability to predators (Cott 1940(Cott , 1946Baker and Parker 1979;Guilford 1986). ...
... Darwin (1871) expanded his initial outline of sexual selection to respond to these critics, and we now view showy plumage as a potential burden, and many investigators have noted that cryptic prey should be less vulnerable to visual hunting predators than conspicuous prey (Cott 1940;Merilata 1999;Merilata and Lind 2005). Indeed, much empirical work supports this claim (e.g., Götmark 1993;Stuart-Fox et al. 2003;), yet ornamented plumage could signal unpalatability (aposematism) or unprofitability to predators (Cott 1940(Cott , 1946Baker and Parker 1979;Guilford 1986). ...
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Because conspicuous morphology such as colorful plumage may increase predation risk, we aimed to see if variation in plumage coloration could explain variation in avian anti-predator behavior. We included several measures of plumage coloration: human perception of vividness from images in field guides, total intensity from reflectance spectra of museum skins, contrasts calculated from physiological models of these spectra parameterized for both raptors and humans, chroma, and spectral saturation. We investigated how well these measurements predicted risk assessment in ten species of birds in St. John, U.S. Virgin Islands. We quantified how each species responded to playbacks of a predator’s calls and compared this response to that elicited by songs from a non-predatory, sympatric bird. We found that human-determined measures of vividness best predicted anti-predator responses of birds—more vividly colored species responded more to predators than duller species. No spectrophotometric variable explained variation in species reactions to a predator call. Our results suggest that vivid birds may compensate for their conspicuousness by being more responsive to the sound of predators and that more work is needed to better evaluate how animal coloration is quantified in comparative studies.
... An example of such a trait is antipredator colouration, which may function by either reducing or increasing prey detectability. On the one hand, cryptic species are difficult to detect by predators (Cott 1940) because their colouration is similar to that of the background (Endler 1978;Ruxton et al. 2004;Cuthill et al. 2005). On the other hand, species that invest in defences Communicated by Oliver Love. ...
... M. Ruiz-Rodríguez (&) Á J. M. Avilés Á D. Parejo Department of Functional and Evolutionary Biology, Estación Experimental de Zonas A ´ ridas (CSIC), Almería, Spain e-mail: magda@eeza.csic.es that make them unprofitable, often advertise their unpalatability by means of conspicuous signals such as sounds and/or odours, but more often exhibit exuberant colour patterns (Darwin 1871;Cott 1940;Dumbacher et al. 1992), which is known as aposematic colouration. ...
... Dumbacher et al. 2004). 3. Kingfishers have been found to be unpalatable in several studies (Cott 1947;Weldon 2000). Furthermore, they may be an unprofitable prey to pursue because of their extremely quick flight, which can be signalled through conspicuous colours as a particular form of aposematism ( Baker and Parker 1979;Götmark 1992;Ruxton et al. 2004;Mappes et al. 2005) and act as a pursuit-deterrence signal (Murphy 2006). ...
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Animals often announce their unprofitability to predators through conspicuous coloured signals. Here we tested whether the apparently conspicuous colour designs of the four European Coraciiformes and Upupiformes species may have evolved as aposematic signals, or whether instead they imply a cost in terms of predation risk. Because previous studies suggested that these species are unpalatable, we hypothesized that predators could avoid targeting them based on their colours. An experiment was performed where two artificial models of each bird species were exposed simultaneously to raptor predators, one painted so as to resemble the real colour design of these birds, and the other one painted using cryptic colours. Additionally, we used field data on the black kite's diet to compare the selection of these four species to that of other avian prey. Conspicuous models were attacked in equal or higher proportions than their cryptic counterparts, and the attack rate on the four species increased with their respective degree of contrast against natural backgrounds. The analysis of the predator's diet revealed that the two least attacked species were negatively selected in nature despite their abundance. Both conspicuous and cryptic models of one of the studied species (the hoopoe) received fewer attacks than cryptic models of the other three species, suggesting that predators may avoid this species for characteristics other than colour. Globally, our results suggest that the colour of coraciiforms and upupiforms does not function as an aposematic signal that advises predators of their unprofitability, but also that conspicuous colours may increase predation risk in some species, supporting thus the handicap hypothesis.
... Sexual selection may relate to interspecific interactions such as those between predators and prey because only individuals of high quality will be able to signal that they are unprofitable prey (Cott, 1947;Baker & Parker, 1979;G€ otmark, 1992, 1993. Because secondary sexual characters often are condition dependent, with only healthy individuals in prime condition being able to develop the most exaggerated secondary sexual traits (Andersson, 1994), we should expect that such individuals are better able to escape from predators, a prediction that has been confirmed in three studies (Petrie, 1992;de Lope & Møller, 1994;Møller & Nielsen, 1997). ...
... If FID in sexually dichromatic species simply reflected the risk of predation, we should have found sexually dichromatic species to have shorter FID than sexually monochromatic species, as we actually found. Predation has been hypothesized to play a role in the evolution of unprofitable prey that signal the difficulty of capture to the predator and hence their unprofitability (Cott, 1947;Baker & Parker, 1979;G€ otmark, 1992, 1993. Here we have shown that sexually dichromatic species have shorter FID than sexually monochromatic species. ...
Article
Predators exert strong selection pressures on their prey. Prey would therefore benefit by adjusting their behaviour to the risk of predation, while predators conversely would benefit from adjusting their behaviour to that of their prey. Extravagant ornamentation has evolved to attract mates and/or successfully compete with conspecifics of the same sex to secure high mating success, even if that occurs at a cost of increased risk of predation. Thus, sexually dichromatic species may be more susceptible to predation than sexually monochromatic species, and the presence of compensation is indicative of such species being more vulnerable. If extravagant ornamentation is costly in terms of predation risk, then we should expect sexually dichromatic species to have longer flight initiation distances (FID) than sexually monochromatic species. If ornamentation is acquired as a handicap with only individuals in prime condition being able to display with the smallest viability cost, we should expect sexually dichromatic individuals to have shorter FID than sexually monochromatic individuals. Such differences among individuals should, on an evolutionary time scale, translate into differences in FID being related to differences in sexual dichromatism among species. We investigated the relationship between FID and sexual dichromatism in phylogenetic analyses, while accounting for effects of continent (Australia, North America, and Europe), body mass, the interaction between sexual dichromatism and body mass and the interaction between sexual dichromatism and continent. In an analysis of 447 species we found shorter FID in sexually dichromatic than in sexually monochromatic species (consistent with the handicap hypothesis because sexually dichromatic species took greater risks), especially so at large body size. FID differed among continents and the relative difference in FID between sexually monochromatic and sexually dichromatic species was larger in Europe than in Australia and North America. These differences among continents may be attributed to latitudinal effects of predation. These findings are important for current ideas about the evolution of secondary sexual characters because they imply covarying continental differences in predation, especially for large bodied sexually dichromatic species.
... Contrary to the SSH assumption of a predation cost of sexually selected conspicuousness, some authors have suggested that this can be an aposematic signal that allows the predators to learn that conspicuous birds are less profitable (Baker andParker 1979, Endler 1991). The ''unprofitable prey hypothesis'' (UPH) assumes that conspicuous birds are less edible (Cott 1947, Götmark 1994 or more difficult to catch and, because of this, predicts that they will be avoided as prey and thus have lower predation risk (Baker and Parker 1979). The term ''difficult to catch'' was originally used in a broad sense to refer to birds with ''good vision and escape potential'' (Baker and Parker 1979:70). ...
... In fact, males are expected to be slightly more profitable than females, given their higher body mass. On the other hand, it is not likely that males were more distasteful than females (Cott 1947, Götmark 1994, because males were the most common prey of the sparrowhawk hunting in our study area (see above). ...
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According to the "sexual selection hypothesis" (SSH), plumage conspicuousness has evolved through mate choice because it signals the quality of the bearer, and this is an honest signal because it involves a predation cost in terms of increased detectability to predators. Alternatively, according to the "unprofitable prey hypothesis" (UPH), conspicuousness is an aposematic signal indicating higher escape potential. We should expect the animals with higher predation risk (either conspicuous or dull, depending on the hypothesis) to have evolved antipredator behaviors to compensate for their higher predation risk (i.e. the "compensation hypothesis"). We tested these hypotheses by studying the vigilance behavior of wintering Eurasian Siskins (Spinus spinus) foraging on three feeders with different predation-risk and competition levels. Males were, on average, 50% more brightly colored than females. Males and females had similar wing loading, which allows us to reject male unprofitability related to higher takeoff speed. Males had shorter mean interscan durations (which improves predator detection) than females, especially at the high-predation-risk feeder (which males avoided), but the sexes did not differ in foraging-bout length, percentage of time spent scanning, and mean scan duration. In males, length of yellow tail stripe and brightness were positively correlated with percentage of time spent scanning. Therefore, our results on vigilance behavior and wing loading support the compensation hypothesis and the SSH assumption of a predation cost of conspicuousness, whereas they reject the predictions of the UPH. Compensation vigilance and other antipredator behaviors are expected to have also evolved in the conspicuous sex in other dichromatic species, and we predict that a correlation between plumage conspicuousness and vigilance should be found in future comparative studies.
... Patch size, brightness, color, and relative distribution on the body greatly influence animal conspicuousness. Predictions on the design of color patterns either maximizing or minimizing detection have long been formulated (Cott 1940). Selection for crypsis should favor (1) patches similar in size, brightness, and color to the mosaic of the background against which the animal is viewed (Endler 1978, 1984); (2) countershading (sensu Ruxton et al. 2004) in environments where light is directional, for example, with ventral parts lighter than dorsal parts in habitats where light comes from above (Hailman 1979; Kiltie 1988); and (3) disruptive coloration, that is, color patches that break the contour and delay animal identification by silhouette-scanning predators or prey (Cott 1940; Hailman 1977; Bradbury and Vehrencamp 1998; Merilaita 1998; Cuthill et al. 2005; Merilaita and Lind 2005). ...
... Hypotheses have long been formulated to explain the adaptive significance of countershaded patterns (Thayer 1896; Cott 1940). Yet this issue has received remarkably little attention with regard to terrestrial organisms (Ortolani and Caro 1996; Ortolani 1999; Stoner et al. 2003a, 2003b). ...
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Understanding how animals achieve simultaneous con- spicuousness to intended receivers and crypsis to unintended re- ceivers requires investigating the distribution, size, and spectral char- acteristics of color patches. Here we characterize plumage patterns of 40 rainforest bird species living in understory or canopy. Visual signals maximizing (or minimizing) detection are expected to differ between these contrasted light habitats, making rainforests appro- priate to test hypotheses of color signal evolution. Using spectrometry and comparative analyses, we show that canopy and understory act as distinct selective regimes that strongly influence bird coloration. Birds reduce detectability by displaying countershaded patterns, by matching background color and contrast, and by reducing in size the most conspicuous patches. More intense on males than on fe- males, selection for conspicuousness acts on large patches by in- creasing contrast on ventral parts likely to be seen by conspecifics. It also operates on small patches by focusing visual contrast on chest, head, and tail in understory and on wing and tail in canopy, by increasing local brightness contrast compared to general contrast in canopy, and by exploiting different wavelengths for contrast (short in canopy and long in understory). These results are of general in- terest to understanding the evolution of color patterns for all or- ganisms living in contrasted light environments.
... Research shows that PCA individuals have made their predators recognize them as food sources that are not profitable so the predation pressure was lower than for the normal individual (Cott 1947;Cott and Benson 1970;Baker and Parker 1979;Gömark 1994) and the reproductive rate of the Melanism type Rock Dove (Columba livia) was higher than that of normal individuals (Murton et al. 1973). ...
Article
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Plumage color aberrations(PCA) cause a lack of, reduction in, and abnormal distribution of pigments in feathers of birds. Although many studies have been conducted to discover the types and mechanisms of PCA, most often the type is wrongly applied because of identification difficulties and confusion. There has been no research on the PCA of birds till recently in Korea. We review the photographs on the PCA of birds in Korea, explain the types and mechanisms, and discuss the chance of survival based on current state of knowledge.
... Pioneering tests by Cott (1947) were among the fi rst to experimentally suggest that predators respond to chemical substances contained in birds. Cott noted that the carcasses of some birds were less palatable than those of others when presented to potential mammalian predators (i.e., humans, domestic cats) or invertebrate scavengers (hornets). ...
... In this context, diverse avian defensive behaviors and strategies have been described in the literature, including some examples relying on chemical compounds. In the 1940s, Cott observed dead laughing doves ( Streptopelia senegalensis L.) being consumed by scavenger hornets ( Vespa orientalis L.) , whilst the fresh carcass of pied kingfi sher ( Ceryle rudis L.) stayed intact because of likely unpalatable components contained in its tissues (Cott 1947 ). The same naturalist conducted experiments on 200 species from 57 families in order to assess the palatability of the eggs and meat for humans, hedgehogs, rats, ferrets, and cats. ...
Chapter
The roles and importance of avian-produced odorous secretions have been largely underestimated. This is mainly due to the supposed absence of a sense of smell in birds, and few studies have been carried out on the ecological relevance of olfactory cues in birds. Despite this, some notable breakthroughs related to avian chemical-mediated interactions have been published during the last 50 years. Nowadays, this field of research is attracting increasing interest from the scientific community. As expected, varied organic compounds, ranging from ubiquitous to highly specific, and from non-volatile to volatile, are being found to be of major importance and provide explanations for various behaviors observed in birds. Even well-known and long-studied relations, such as interspecific brood parasitism, are subject to this renewed interest. For a non-evicting brood parasitic cuckoo, we recently revealed unforeseen implications of malodorous secretions produced by the juvenile cuckoo when frightened by an intruder. Such emissions contribute to the protection of the entire nest against mammalian and avian predators, reducing or cancelling out anticipated negative effects of parasitism on average host fitness. In this particular case and depending on the predator pressure, the production of the repulsive secretion by the cuckoo chicks may thus turn the initial parasitic situation into a mutualism. This is the first time such a reversal of situation has been documented thoroughly. Evolutionary consequences resulting from this phenomenon might include the lack of defenses against brood parasites observed in hosts, and an absence of the classic arms race seen in other interspecific host–brood parasite cases. The conclusive evidence of this unexpected fluctuation from parasitism to mutualism was obtained with long-term field monitoring, translocation of nestlings, chemical analysis of natural secretions, synthesis of an artificial blend mimicking the foul-smelling defense, and repellency tests on representative host nest predators. Here, we review the ways that some bird species use their sense of smell and olfactory information to interact with the environment, congeners, or predators. After this synopsis, we relate how our modern approach, combining evolutionary ecology and odorous signaling in birds, led to recent novelty in the field of host–brood parasite interactions. In the final stage, we present our further directions and perspectives for research related to the importance of stinking defensive secretions in interspecific brood parasite interactions.
... First, coloration may be aposematic and thereby signal unprofitability to potential predators (for a review see Baker and Parker 1979). Second, coloration could be cryptic whereby external coloration generally de-creases detectability by predators through background matching (Cott, 1946;Endler, 1978). Third, a color could increase the detectability of an individual while not providing any aposematic benefits, as in the case of social ornaments (Møller and Nielsen, 2006). ...
Article
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The distance from an approaching threat at which animals initiate flight-flight-initiation distance (FID)-is a sensitive metric of variation in risk, but the effects on FID associated with the risk of possessing highly detectable external coloration are unknown. We tested whether variation in the degree of plumage vividness in birds explained variation in flight-initiation distance. After controlling for body mass, the distance at which the experimental approach began, and phylogenetic relatedness, plumage vividness was not a predictor of FID. Contrary to the expectation that vividness affects risk, and therefore risk assessment , these results suggest that birds do not compensate for greater visual conspicuousness by fleeing sooner from approaching threats [Current Zoology 61 (4): 773–780, 2015].
... The more recent reviews on bird toxicity do not include unpalatable or malodorous birds in their classification of poisonous birds (Bartram and Boland, 2001;Mebs, 2002). There is, however, an extensive body of evidence on this subject, chiefly from experimental work carried out by Cott (Cott, 1945(Cott, , 1946(Cott, , 1948(Cott, , 1954Cott and Benson, 1970), and by surveying field and museum ornithologists (Weldon and Rappole, 1997). ...
Article
Until very recently, toxicity was not considered a trait observed in birds, but works published in the last two decades started to shed light on this subject. Poisonous birds are rare (or little studied), and comprise Pitohui and Ifrita birds from Papua New Guinea, the European quail, the Spoor-winged goose, the Hoopees, the North American Ruffed grouse, the Bronzewings, and the Red warbler. A hundred more species are considered unpalatable or malodorous to humans and other animals. The present review intends to present the current understanding of bird toxicity, possibly pointing to an ignored research field. Whenever possible, biochemical characteristics of these poisons and their effects on humans and other animals are discussed, along with historical aspects of poison discovery and evolutionary hypothesis regarding their function. Copyright © 2015. Published by Elsevier Ltd.
... Some forms of conspicuous coloration, involving sharp borders and bright contrasting colours, may serve to warn experienced predators of distastefulness or other danger. For example, some brightly marked waders such as the Redwattled Lapwing Vanellus indicus and Egyptian Plover have been judged to be distasteful (to a tiger cub and man respectively), and others such as the Northern Lapwing and Eurasian Oystercatcher Haematopus ostralegus mildly distasteful (to man) (information cited in Cott 1947). Moreover, the Blacksmith Plover Vanellus armatus has been observed giving an aposematic display in which the bird reacted to a fast low approach by a Lanner Falcon Falco biarmicus by facing it with its wings partly spread and calling loudly (Thomas 1983). ...
Article
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At least 16 of the hypotheses that have been proposed to explain the evolution of plumage colour and pattern in birds may be applicable to waders -five straightforward physical explanations, and the rest involving some form of communication between animals. Eight of the latter involve communication between different species (such as predator and prey) and the rest involve communication between individuals of the same species (such as potential mates). These hypotheses are reviewed and an additional one based on social selection proposed.
... Moreover, congruence among predator species in their responses to defensive chemicals is usually substantial (Pasteels & Grégoire, 1983). For example, hornets, cats and humans ranked the taste of bird meat similarly (Cott, 1947). However, rarely is palatability of butterflies rated using more than one potential predator (Trigo, 2000), and differences in type of chemical defence most effective to different classes of predators have been noted as well. ...
Article
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Quantification of chemical defence contributes to the study of animal signals, and to understanding trade-offs among defences and life history traits. Some tropical fruit-feeding butterfly species can be expected to have well-developed anti-predator defences because they are long-lived, are host-plant specialists, and/or have contrasting colourations that may be involved in mimicry relationships. Yet, as a group they are often assumed to be palatable, even without supporting data. Palatability is a continuum that embraces within and between prey-species variation, and therefore, both among- and within-species variation must be documented. Palatability of nine species of fruitfeeding butterfly in Uganda was rated using a novel assay. One hundred and twenty-five butterflies were homogenized, their ground tissues suspended in sugar water and these suspensions offered as small droplets to individual ants in Petri dishes. The time ants spent feeding on these droplets was measured. Danaine butterflies were used as unpalatable references, and sugar solution as a palatable reference. Ants tended to eat in significantly shorter bouts from danaines compared to fruitfeeding species, and feeding bouts on pure sugar solution were longest. Within fruit-feeding species, variation in the duration of ants’ feeding bouts was very substantial. There was also considerable variation among individual ants, such that large sample sizes would be needed to reliably distinguish palatability of different species of fruit-feeding butterflies. In explorative analyses, at least three fruitfeeding butterfly species that were assumed palatable appeared to be chemically defended. These results suggest that, in contrast to common assumptions, some tropical fruit-feeding butterflies use unpalatability for defence, perhaps contributing to their long life spans in the wild.
... Pioneering tests by Cott (1947) were among the fi rst to experimentally suggest that predators respond to chemical substances contained in birds. Cott noted that the carcasses of some birds were less palatable than those of others when presented to potential mammalian predators (i.e., humans, domestic cats) or invertebrate scavengers (hornets). ...
... Such secondary sexual characters are developed and maintained at a viability cost, for example, in terms of increased risk of predation or parasitism. The mere presence of bright coloration or other costly signals may provide reliable information in prey–predator interactions because high quality prey individuals would signal that they were unprofitable (Cott 1947; Baker and Parker 1979; Götmark 1992, 1993). Brightly colored males may signal the absence of parasites and the presence of an efficient immune system that would make it difficult for a predator to be successful in a pursuit (Møller et al. 2004). ...
Article
Sexual selection that results in the evolution of exaggerated secondary sexual characters has been hypothesized to impose production and maintenance costs of such traits on their bearers. Costs arising from sexual selection could increase the intensity of predator-mediated natural selection, leading to the prediction that species with exaggerated secondary sexual characters should be particularly susceptible to predation. We tested this prediction in a comparative analysis based on 31,745 prey individuals belonging to 66 species of birds collected from a total of 937 breeding events by 33 to 66 different pairs of European sparrowhawks Accipiter nisus annually during a period of 21years. To assess vulnerability of different species we estimated a prey vulnerability index based on the difference in the logarithmically transformed absolute abundance of prey minus the logarithmically transformed expected abundance as determined by population density of breeding birds. The prey vulnerability index was predicted by sexual dichromatism, accounting for 23% of the variance in risk of predation among species, even when considering similarity in phenotype among species due to common descent (in the latter case explaining 12% of the variance). This finding suggests that sexual selection is an important evolutionary force-affecting predator–prey interactions.
... Although mimicry associated with toxicity is often xed, in that the attributes of the animal stay constant for long periods, it can also be turned off and on behaviourally, as has been shown, for example, in a octopus that changes colour to mimic venonmous animals when confronted by danger (Norman et al. 2001). In birds, the connection between mimicry and toxicity has not been made very often because evidence for toxicity in birds was lacking (but see Cott 1947). Instead, mimicry in xed attributes of birds, such as plumage, was attributed to birds signalling to other birds with which they interact socially (hence the term social mimicry; Moynihan 1968) rather than to predators. ...
... may function as warning coloration , to inform potential predators that these are " speedy, wary birds not worth the effort of trying to catch " (Cloudsley-Thompson 1999). Cott (1947) examined plumage coloration of species of Middle Eastern birds and found that conspicuous birds, such as the White-crowned Black Wheatear Oenanthe leucopyga, had flesh that was more unpalatable to cats and hornets than cryptic species . Cott's (1947) theory was supported by a recent study by Götmark (1994), although some species do not fit the hypothesis (Götmark & Unger 1994). ...
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Since Buxton's (1923) observation that many animals inhabiting desert environments exhibit black pelage, various hypotheses have been proposed to explain the evolutionary origins of this phenomenon. In this review, these hypotheses are examined for species of desert-inhabiting birds. Possibly, since dark feathers are more resistant to abrasion, they protect the inner organs from damage by ultraviolet radiation. Another physiological hypothesis states that radiative heat load at skin level and the risk of heat stress can be reduced in dark-coloured species. This could be modified by behavioural adjustments. Alternatively, dark plumage may facilitate social signalling. Black provides maximum contrast against the pale desert substrate during daylight, and may provide camouflage at night. These hypotheses are not mutually exclusive. However, we cannot exclude the possibility that dark plumage traits persist in desert species simply because of shared ancestry rather than adaptation. To disentangle the alternative hypotheses, and better understand the relative importance of different selection pressures in the evolution of dark coloration in desert birds, we suggest there is a need for further studies, including comparative studies that control for phylogeny.
... The role of predators and parasites in the evolution of host sexual selection constitutes a prime example of multiple interactions. Cott (1947) and Baker and Parker (1979) suggested that secondary sexual characters may signal the degree of lack of profitability of prey because individuals with the most exaggerated secondary sexual characters also have the greatest ability to escape predation. Baker and Parker (1979) and Baker and Bibby (1987) showed in comparative analyses that bird species had differentially exaggerated sexual visual signals in parts of the body that were most likely to be exposed to predators during a predator attack. ...
Article
Ecological interactions such as those between predators and prey, parasites and hosts, and pollinators and plants are usually studied on their own while neglecting that one category of interactions can have dramatic effects on another. Such interactions between interactions will have both ecological and evolutionary effects because the actions of one party will influence interactions among other parties, thereby eventually causing feedback on the first party. Examples of such interactions include the effects of predators and parasites on the evolution of host sexual selection, the effects of parasites and predators on the evolution of virulence, and the effects of parasites and predators on the evolution of pollinator mutualisms. Such interactions among interactions will generally prevent simple cases of coevolution, because any single case of interaction between two parties may be affected by an entire range of additional interacting factors. These phenomena will have implications not only for how ecologists and evolutionary biologists empirically study interactions but also on how such interactions are modeled.
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Two introduced carnivores, the European red fox Vulpes vulpes and domestic cat Felis catus , have had extensive impacts on Australian biodiversity. In this study, we collate information on consumption of Australian birds by the fox, paralleling a recent study reporting on birds consumed by cats. We found records of consumption by foxes on 128 native bird species (18% of the non-vagrant bird fauna and 25% of those species within the fox’s range), a smaller tally than for cats (343 species, including 297 within the fox’s Australian range, a subset of that of the cat). Most (81%) bird species eaten by foxes are also eaten by cats, suggesting that predation impacts are compounded. As with consumption by cats, birds that nest or forage on the ground are most likely to be consumed by foxes. However, there is also some partitioning, with records of consumption by foxes but not cats for 25 bird species, indicating that impacts of the two predators may also be complementary. Bird species ≥3.4 kg were more likely to be eaten by foxes, and those <3.4 kg by cats. Our compilation provides an inventory and describes characteristics of Australian bird species known to be consumed by foxes, but we acknowledge that records of predation do not imply population-level impacts. Nonetheless, there is sufficient information from other studies to demonstrate that fox predation has significant impacts on the population viability of some Australian birds, especially larger birds, and those that nest or forage on the ground.
Article
We review the literature on warning coloration in birds starting from Alfred Russel Wallace's premise that aposematism may advertise difficulty in subduing prey rather than simply unpalatability. Across diverse taxa, there is a good deal of anecdotal information to suggest that signals, usually involving conspicuous coloration, are associated not only with distastefulness but with informing predators that prey will be difficult to catch. There are also examples of aposematism being associated with both Müllerian and Batesian mimicry. In Aves there are now several examples of competitive mimicry which involves resembling larger non-predator species. We stress that broad-sense aposematism dissuading predators from attack can operate throughout the predatory sequence in birds. Throughout, we suggest new avenues of research that are likely to be promising and which will reinvigorate rigorous research on warning coloration in birds.
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As nontraditional model organisms with extreme physiological and morphological phenotypes, snakes are believed to possess an inferior taste system. However, the bitter taste sensation is essential to distinguish the nutritious and poisonous food resources and the genomic evidence of bitter taste in snakes is largely scarce. To explore the genetic basis of the bitter taste of snakes and characterize the evolution of bitter taste receptor genes ( Tas2r s) in reptiles, we identified Tas2r genes in 19 genomes (species) corresponding to three orders of non-avian reptiles. Our results indicated contractions of Tas2r gene repertoires in snakes, however dramatic gene expansions have occurred in lizards. Phylogenetic analysis of the Tas2r s with NJ and BI methods revealed that Tas2r genes of snake species formed two clades, whereas in lizards the Tas2r genes clustered into two monophyletic clades and four large clades. Evolutionary changes (birth and death) of intact Tas2r genes in reptiles were determined by reconciliation analysis. Additionally, the taste signaling pathway calcium homeostasis modulator 1 ( Calhm1 ) gene of snakes was putatively functional, suggesting that snakes still possess bitter taste sensation. Furthermore, Phylogenetically Independent Contrasts (PIC) analyses reviewed a significant correlation between the number of Tas2r genes and the amount of potential toxins in reptilian diets, suggesting that insectivores such as some lizards may require more Tas2r s genes than omnivorous and carnivorous reptiles.
Article
In many animal taxa, non-toxic species demonstrate Batesian mimicry - appearing or behaving similarly to harmful species - thereby reducing their attractiveness to predators. A potential example of Batesian mimicry occurs in Papua New Guinea (PNG), where birds of the genus Pitohui have been found to contain toxic compounds; pitohuis are frequent members of mixed-species flocks and several observers have hypothesised that species in flocks are imitating each other in their plumage and vocalisations. If non-toxic species participate in flocks to associate with pitohuis, we predicted that pitohuis should play an important role in flocks, such that flock composition should be strongly influenced by their presence, and that other species should be attracted towards their vocalisations. We found, however, that in the lowland rainforests of Madang Province, flock composition was less influenced by the presence of pitohuis than by the presence of Rufous Babblers (Pomatostomus isidori), a non-toxic leading species. In playback experiments, Rufous Babblers were as attractive to heterospecifics as pitohuis. Our study provides the first empirical test of the connection between toxicity and flock organisation in PNG and our primarily negative results suggests that toxicity does not drive the organisation of flocks in our study area.
Article
Geographers have increasingly begun to attend to the local environments of science, considering how these spaces shape and influence knowledge production. This paper will explore the insights a spatial analytic can contribute to the history of science by exploring one scientific performance space; the field site. Already, rich and insightful studies into the geographies of field science have figured these sites as complex, subjective and lively places. However, so far, there appears to have only been peripheral attention paid to the multiple and myriad nonhuman animals that are present in the field. The field is a site where animals have been the object of study, provided transport, companionship, sport and food, but their presence within the history of field science is conspicuously absent. This paper asks how to study the spatialities of animal lives enrolled in the diverse technologies and knowledge that encompass scientific practice, and considers what such an engagement could offer to contemporary scientific study. Therefore, this paper will review animal and hybrid geographies, and methodological tools that attend to the performativity of science, such as the actor–network theory and Pickering's ‘the mangle’. It will consider what these literatures and conceptual frameworks can add to understandings of the historical, social, cultural and political nature of more-than-human knowledge through a consideration of field science.
Article
In studies of sexual selection in birds, it is necessary to quantify the conspicuousness and sexual dimorphism of the plumage. We present a method, based on the Munsell colour system, that is easier to use than spectroradiometric techniques. It is based on measurable and repeatable data, although it is dependent on human vision. It provides indices of sexual dimorphism and incorporates aspects of close-range and long-distance conspicuousness. Ten species of Emberezidae were chosen to illustrate the procedure, and it was tested using naive observers. It consists of dividing the body of a bird into regions and matching the colour of each region to chips in a colour guide. The following indices based on the parameters of the Munsell system were selected: value (V), chroma (C), and Munsell power (V∙C), which measure conspicuousness independently of the background; Wv, Wc, and Wv∙c, which measure the contrast between the colours in the plumage; Bv, Bc, and Bv∙c, which measure the contrast between the bird and its background; and Dv, Dc, and Dv∙c, which are the indices of sexual dimorphism of the plumage. There was a high degree of agreement among the naive observers, and the scores obtained using field guides did not differ significantly from those recorded on museum specimens. One of the dimorphism indices (Dv∙c) was found to give more information than the others. However, our results indicate that conspicuousness and dimorphism indices should not be used individually because they are interdependent, and that they should be used in conjunction with multivariate analyses. Also, the proposed method incorporates long-distance conspicuousness into the results.
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Certain bright colors of butterflies are often interpreted to signal that they are chemically defended, meaning that they are unpalatable or toxic to predators. We discuss several questions concerning predation on butterflies and how chemical defense might work. An important gap in our understanding is quantitative information about palatability on a community level. Here we present a novel method to quantify palatability used on 29 species of butterflies in a tropical forest in Uganda. Butterflies were mashed and offered as small drops to individual ants in Petri dishes. Ants tended to eat in shorter bouts from less palatable butterflies. The first results clarify one mimicry relationship as Batesian (one is unpalatable, the other is palatable), whereas another appeared more Müllerian (both are moderately unpalatable). Surprisingly, some brown (cryptically) colored butterflies also seemed to be chemically defended. Within one of the species we detected that individuals become more palatable as they age. We found no difference between the sexes in this species.
Article
Two groups of male chicks (Gallus gallus) were allowed to peck at distasteful food (chick crumbs flavoured with quinine and mustard) that either matched or contrasted with the background on which the food was presented. The experiment consisted of a series of trials, each of which was terminated when a fixed amount of food (four crumbs) had been ingested. Within-trial pecking rate was initially higher in the group given constrasting food, confirming that degree of contrast between a prey item and its background increases the likelihood of detection by a naive predator. However, during the series of training trials pecking rate declined faster, and reached a lower level, in the group given contrasting food than in the group given matching food. Thus, rate and strength of avoidance learning are affected by the degree to which distasteful food contrasts with its background. This may explain why many distasteful prey species are brightly coloured, despite the fact that bright colouration increases the likelihood of initial detection by a predator.
Article
The paper describes the results of an investigation of the relative acceptability of the eggs of twenty-five species of birds, belonging to ten orders, as illustrated by the feeding preferences of the Hedgehog (Erinaceus europaeus). In each of 332 experiments, one of four animals used as tasters was presented with a choice as between two egg-samples. Possible disturbing factors such as differences in egg-size or shell-coloration, and those due to spatial arrangement of the samples, were eliminated by the use of raw egg, offered in equal quantities, and by the successive reversal in position of the egg-species matched within a particular group of experiments, or as offered to a particular experimental animal.
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Full-text available
Bright colors in birds might signal that they are undesirable as prey (aposematic), an idea that has been difficult to test. When stuffed pied flycatchers Ficedula hypoleuca are exposed to migrating sparrowhawks Accipiter nisus in spring or in autumn, the hawks attack cryptic females more often than bright males. To achieve better statistical control and to assess whether male plumage also reduces predation risk in the breeding season and in the nesting habitat of the pied flycatcher, I placed pairs of male and female flycatcher mounts in similar positions near 22 nests of sparrowhawks. The hawks attacked mainly female mounts, verifying that the preference is real. The sparrowhawks caught at least 19 live pied flycatchers; 12 young, 5 adult males, 1 adult female, and 1 female or young. Hawks that caught an adult male seemed to prefer attacking female mounts. I discuss three interpretations of these results, suggesting that black-and-white male flycatchers may benefit from being a novel and aberrant prey, at least early in the breeding season.
Article
The bitter rejection response consists of a suite of withdrawal reflexes and negative affective responses. It is generally assumed to have evolved as a way to facilitate avoidance of foods that are poisonous because they usually taste bitter to humans. Using previously published studies, the present paper examines the relationship between bitterness and toxicity in mammals, and then assesses the ecological costs and benefits of the bitter rejection response in carnivorous, omnivorous, and herbivorous (grazing and browsing) mammals. If the bitter rejection response accurately predicts the potential toxicity of foods, then one would expect the threshold for the response to be lower for highly toxic compounds than for nontoxic compounds. The data revealed no such relationship. Bitter taste thresholds varied independently of toxicity thresholds, indicating that the bitter rejection response is just as likely to be elicited by a harmless bitter food as it is by a harmful one. Thus, it is not necessarily in an animal's best interest to have an extremely high or low bitter threshold. Based on this observation, it was hypothesized that the adaptiveness of the bitter rejection response depends upon the relative occurrence of bitter and potentially toxic compounds in an animal's diet. Animals with a relatively high occurrence of bitter and potentially toxic compounds in their diet (e.g., browsing herbivores) were predicted to have evolved a high bitter taste threshold and tolerance to dietary poisons. Such an adaptation would be necessary because a browser cannot "afford" to reject all foods that are bitter and potentially toxic without unduly restricting its dietary options. At the other extreme, animals that rarely encounter bitter and potentially toxic compounds in their diet (e.g., carnivores) were predicted to have evolved a low bitter threshold. Carnivores could "afford" to utilize such a stringent rejection mechanism because foods containing bitter and potentially toxic compounds constitute a small portion of their diet. Since the low bitter threshold would reduce substantially the risk of ingesting anything poisonous, carnivores were also expected to have a relatively low tolerance to dietary poisons. This hypothesis was supported by a comparison involving 30 mammal species, in which a suggestive relationship was found between quinine hydrochloride sensitivity and trophic group, with carnivores > omnivores > grazers > browsers. Further support for the hypothesis was provided by a comparison across browsers and grazers in terms of the production of tannin-binding salivary proteins, which probably represent an adaptation for reducing the bitterness and astringency of tannins.(ABSTRACT TRUNCATED AT 400 WORDS)
Article
Preface; Introduction; 1. The downfall of classical physics; 2. Relativity; 3. Time; 4. The running-down of the universe; 5. 'Becoming'; 6. Gravitation: the law; 7. Gravitation: the explanation; 8. Man's place in the universe; 9. The quantum theory; 10. The new quantum theory; 11. World buildings; 12. Pointer readings; 13. Reality; 14. Causation; 15. Science and mysticism; Conclusion; Index.
Article
IT has previously been shown1 that hungry cabbage butterflies give a specific response, ``spontaneous feeding response'', on red, yellow, blue and violet papers, but not on green, bluish green or grey of any shade between black and white. Whether the insects confused green and bluish green with grey could not be investigated as they could not be trained on these colours.
Article
1. Die Bienen lassen sich darauf dressieren, in einem Zimmer mit verminderter Tageslichtbeleuchtung auf Ausschnitten aus einem kontinuierlichen Spektrum oder auf Spektrallinien zwischen etwa 650 μμ und 313 μμ Wellenlänge wie auch auf Streifen unzerlegten Lichts Futter zu suchen. Nachdem sie auf den Feldern, die hell auf dem dunkleren Untergrund erscheinen, mit Zuckerwasser gefüttert wurden, fliegen sie diese Felder auch ohne Futter an und sammeln sich darauf. Der Sichtbarkeitsbereich der Wellenlängen ist also für die Bienen auf der roten Seite unserem Sehen gegenüber verkürzt, reicht aber bis tief ins Ultraviolett hinein. 2. Die Bienen lassen sich nicht auf eine bestimmte Helligkeit einer Lichtsorte (unzerlegten Lichts oder eines Spektrallichts) dressieren. Werden sie bei der geringsten Helligkeit einer Lichtsorte gefüttert, die sie auf dem Tisch eben noch finden, so bevorzugen sie doch immer das hellste Feld, wenn man ihnen von derselben Lichtsorte verschieden helle Felder zur Prüfung ohne Futter vorlegt. Wenn sich also die Bienen auf die Unterscheidung verschiedener Lichtsorten dressieren lassen, so können diese Lichtsorten für die Blenen nicht nur in ihrer Helligkeitswirkung verschieden sein. 3. Die Bienen unterscheiden alle Wellenlängen des Spektrums zwischen ungefähr 650 μμ und ungefähr 313 μμ von unzerlegtem Licht. Bietet man den Bienen nach Fütterung auf einer Spektrallinie oder einem Spektralausschnitt neben ihrer Dressurwellenlänge das unzerlegte Licht des Spaltbildes, das sicher heller ist als jeder Teil des Spektrums, so wird doch die Dressurwellenlänge bevorzugt. Werden Bienen auf der geringsten Helligkeit unzerlegten Lichtes gefüttert, bei der sie das Feld noch anfliegen, so bevorzugen sie das weiße Dressurlicht vor Spektralausschnitten, die den Bienen sicher heller erscheinen als jene minimale Weißhelligkeit; denn wenn man auf diese Spektralausschnitte dressiert hat, kann man deren Helligkeit noch um einen bestimmten Betrag herabsetzen, ohne daß die Bienen den Anflug einstellen. 4. Innerhalb des für sie sichtbaren Spektrums unterscheiden die Bienen vier Reizqualitäten. Die 1. reicht von 650 μμ bis ungefähr 500 μμ und umfaßt unser kurzwelliges Rot, Gelb und Grün, die 2. von ungefähr 500 μμ bis 480 μμ (Blaugrün), die 3. von ungefähr 480 μμ bis 400 μμ, unser Blau und Violett umgreifend. Zwischen den Wellenlängen von ungefähr 500–530 μμ und ungefähr 480–460 μμ liegen schmale Übergangsgebiete zwischen der 1. und der 2. und der 2. und der 3. Reizqualität. Diese Übergangsgebiete erscheinen den Bienen beiden Nachbarqualitäten ähnlich. Jenseits von 400 μμ folgt im Ultraviolett eine 4. Reizqualität, die bis gegen 310 μμ reicht. 5. Pigmentpapierversuche zeigen für die Bienen die Erscheinung des simultanen Farbenkontrastes. Ein graues Feld in gelber Umgebung erhält für den Lichtsinn der Bienen den Reizwert von Blau; denn es wird von Bienen aufgesucht, die auf Blau dressiert sind. Ebenso kann blauviolette Umgebung einem Graufeld den Reizwert von Gelb erteilen.
Article
Attention is especially directed to two aspects of the relations between preyer and preved upon.First, that there are many factors which determine whether or not, at any particular time, one animal will prey upon another, of which relative palatability is only one. In order, therefore, to demonstrate a difference in palatability between various foods, all these determining factors must be taken into account,Second, that observations indicate that both birds and fish are deluded by rough resemblances to the insects upon which they are at the time feeding.
Article
Summary1. The purpose of this paper is to give an account of certain aspects of the natural history of East African tree-frogs belonging to the genera Hyperolius, Megalixalus, and Leptopelis. The material upon which it is based was obtained by the writer in the palm-forest region of the lower Zambesi Valley during the Zoological Society's Expedition of 1927.2. In particular, a detailed investigation of the food-habits of tree-frogs, as indicated by the examination of food eaten under natural conditions, has been made (1) in order to test the efficiency of procryptic and warning colours, and mimicry, in defending insects from predatory attack; and (2) to indicate the part played by these batrachians as a factor in the production of adaptive coloration in insects.3. The general habits, habitat, and abundance of the frogs are described. It is suggested that the colour-scheme and resting posture of M. fornasinii have a concealing and aggressive function which enables the species to exploit an abundant source of food available in the active, alert, and strongly-flying Odonata, muscid Diptera, and Lepidoptera—groups which are relatively inaccessible to, and little eaten by, the other tree-frogs whose habits were investigated.4. In H. argus certain differences have been observed (1) in the feeding-habits of the sexes, and (2) in the choice of habitat. These have been correlated respectively with the difference in the size of the sexes and with the marked sexual dichromatism in the species. The conspicuous colouring of the female, associated as it is with aposematic habits, may have a “warning” significance.5. Frogs are preyed upon by numerous enemies. They are hunted by small carnivorous mammals, by monitors, by fish, and by members of their own order; they are eaten by a wide range of birds, including crows, shrikes, kingfishers, owls, eagles, harriers, herons, bitterns, ibises, hammer-heads, and spoonbills; and they are relentlessly persecuted by snakes, especially tree-snakes, which probably rank first in importance as enemies of tree-frogs in East Africa.6. The stomach-contents of 798 tree-frogs belonging to the following species are tabulated (the figures refer to the number of frogs examined and to the number of food-animals recovered):—Hyperolius marmoratus, 40 (2675); H. bayoni, 110 (3688); H. argus, 254 (3300); Megalixalus fornasinii, 360 (1119); M. brachycnemis, 11 (31); Leptopelis johnstoni, 8 (13); Phrynobatrachus acridoides, 15 (602).7. 11,428 insects and other food-animals were obtained from this source, representing 11 orders and at least 153 species. Taken collectively, this material comprises the following groups of animals:—Hymenoptera, 87.16 per cent.; Hemiptera, 5.84; Diptera, 3.40; Coleoptera, 1.88; Lepidoptera, .70; Orthoptera, .46; Araneida, .34; Odonata, .15; Isopoda, 04; Isoptera, 02; Batrachia, .01.8. There is a close general similarity in the food-habits of the three species of Hyperolius examined. Ants (Pheidole megacephala) in each case comprise more than 90 per cent, of the total; Hemiptera, Coleoptera, and Diptera, in varying proportions, make up the bulk of the remaining food. In contrast to the above, Megalixalus fornasinii is essentially a fly-catching frog—Diptera comprising the bulk of the food eaten.9. The frogs are considered in relation to their biological environment, with special reference to enemies and prey, and an attempt has been made to indicate certain “food-chains” in which they form an essential link. There is evidence that these forms may be reckoned among the main predatory enemies of small insects in the tropics, and it is suggested that their depredations are not without economic value to man.10. Ants, which are usually regarded as well-defended insects, are widely used as food by frogs. Collected records of stomach examinations made by thirty-five investigators (embracing data relating to 153 species of Anura and to some thousands of individuals) shows that about 60 per cent, of the species examined include ants in their diet. This figure is only slightly exceeded in the case of one other kind of prey, namely, beetles.11. In the present material ants are represented by 9937 out of 11,428 food-animals. The seven species examined each preys upon ants. These insects comprise the main food of the following species:—H. marmoratus, H. bayoni, H. argus, P. acridoides, and M. brachycnemis, the percentage of ants in terms of total food-content being 98, 96, 93, 92, and 77 respectively.12. In three species over 90 per cent, of the frogs containing recognizable food had been feeding upon ants. The figures for each species are as follows:—P. acridoides, 100 per cent.; H. bayoni 97; H. marmoratus, 92; H. argus, 79; M. brachycnemis 78; L. johnstoni, 33; M. fornasinii, 27.13. One is forced to conclude from these facts that the various phenomena of ant-resemblance, in so far as frogs are concerned, can have little, if any, adaptive significance.14. Hymenoptera (other than ants) comprise a significantly low percentage of the food, being represented by 20 specimens (i. e., .18 per cent, of food-animals) obtained from the stomachs of 18 frogs (i. e., less than 2–3 per cent, of those examined).15. The food-animals of the frogs have been classified according to colour, and the results are graphically shown for each of the following groups:—Orthoptera, Hemiptera, Coleoptera, Diptera, Hymenoptera, and Araneida. Of 10,968 specimens sufficiently complete for analysis, not more than 48 insects are conspicuously coloured, and of these only 14 specimens (.13 per cent.) belong to the typically aposematic group.16. These observations lend strong additional support to the classes of facts upon which the theory of warning colours rests: (1) that conspicuous pattern and colour in insects are typically associated with disagreeable or dangerous attributes which render their owner (relatively) unpalatable; (2) that insectivorous enemies learn by experience in nature to recognize and to avoid unpalatable prey; (3) that in leading to immediate recognition by enemies, and by checking the fatalities and injuries caused by experimental tasting, aposematic habits and colour are of vital benefit to their possessor.17. Tree-frogs are serious enemies of small insects in the tropics. They depend mainly upon sight in hunting and capturing prey. There are grounds for believing that they exercise discrimination in the choice of food, and that they learn to recognize and avoid unpalatable prey. There is strong presumptive evidence that aposematic colour and habit assist frogs in the recognition of distasteful species. The food-habits and mental equipment of tree-frogs is such as to suggest their claim to a not unimportant share with birds and lizards in the production, through natural selection, of procryptic and aposematic coloration in insects.
Article
1. Tagfalter besitzen einen ausgesprochenen Farbensinn. 2. Bei einigen der untersuchten Arten wurde durch Farbreize bereits bei frisch geschlpften Tieren, also vor jeder Erfahrung, eine deutliche Nahrungsreaktion ausgelst. 3. Die untersuchten Arten bevorzugen spontan unter den Pigmenten der Heringschen Serie die roten, gelben und gelbgrnen Nr. 1 bis 7 und die blauen, violetten und purpurnen Nr. 12–15 (16) vor den grnen und blaugrnen Nr. 8–11 und den grauen Pigmenten. Jede Art hat innerhalb jener bevorzugten Farbgebiete bestimmte Lieblingsfarben 4. Tagfalter knnen, wenn auch in geringem Mae, Assoziationen bilden und diese mindestens 24 Stunden lang im Gedchtnis behalten. Ihr Verhalten wird jedoch in erster Linie instinktiv bestimmt. 5. Der Sichtbarkeitsbereich des Spektrums reicht am langwelligen Ende fr die Tagfalter weiter als fr Bienen und andere Insekten. Die Bevorzugung von Rot und Purpur durch manche Tagfalter steht im Einklang mit der Frbung typischer Tagfalterblumen. 6. Innerhalb der Farbenreihe lassen sich folgende Bezirke als besondere Reizqualitten mit Sicherheit abgrenzen: ein Gelbbezirk, ein. Blaubezirk und ein zwischen beiden liegender schmaler Bezirk, der die grnen und blaugrnen Pigmente Nr. 8–11 der Heringschen Serie umfat (wahrscheinlich entsprechend der Blaugrn-Qualitt der Bienen.) Da innerhalb des Gelb- und des Blaubezirks noch feinere Abstufungen unterschieden werden, ist durch manche Beobachtungen wahrscheinlich gemacht. 7. Beim ersten Auffinden der Blten dient den Tagfaltern, je nach der Art, bald mehr die Farbe, bald mehr der Duft, meist aber beide zusammen, als Lockmittel. Der Duft dient auch als Alarmierungsmittel. Beim spteren Wiederfinden dient hauptschlich die Farbe als Merkzeichen.
Article
Publicado originalmente en 1898 por Sampson Low, Martston & Co Incluye índice
Article
by Herbert G. Ponting ... with 164 photographic illustrations by the author, 11 by Captain Scott and others, a map & 2 drawings, and an introduction by Lady Scott.
The Fauna of British India
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Birds of L a PZata Threat and warning coloration itr birds. /'roc. 8th I n l The present standing of' the theory of sexual selection
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The Book of Indian Birds Lake Ngami The Coloration of Sea Birds. Birds of Britain
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Odd Edibles. Fie& 186, 269 53-77. BELT, THOMAS (1874). The Naturalist in Nicaragua
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Memories of the Months
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Bird Life of the Borders
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CEAPW, ABEL. (1907). Bird Life of the Borders. London. CHAPMAN, ABEL. (1930).
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An Explorer and his Birds The Birds of British Cruiam. London. ELYOT. (1549). (hstel of Helth. London. EVANS, A. 11. (192'2). Birds. Camb Itidian Sporti.ng Birds Aniphibiu and Reptiles
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CHISHOLM, A. H, (1 945). An Explorer and his Birds. CWBB, CHARLES. (1916). The Birds of British Cruiam. London. ELYOT. (1549). (hstel of Helth. London. EVANS, A. 11. (192'2). Birds. Camb. Nat. Hist., London..FINN, P. (1913). Itidian Sporti.ng Birds. London. GADOW, H. (1923). Aniphibiu and Reptiles. Clambs. Nat. Hist., London. GODMAN, FREDERICK DU CANE. (1907-10).