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Townsend.760/sandbox Amat, JA, et.al. 2010. Greater flamingos Phoenicopterus roseus use uropygial secretions as make-up. Behavioral Ecology and Sociobiology. 65(4): 665-673.  The greater flamingo has plumage that is very recognizable. This study looked at preen oils that contained carotenoids that were secreted by the flamingo. The carotenoids in the uropygial secretions matched those in the pigments of the feathers of the flamingo. These secretions were shown to increase the brightness of the color of feathers as the quantity of these pigments increased and this is called cometic coloration. These secretions were more frequent around breeding times and they were shown to influence mate choice due to the more colorful plumage and birds with the more colorful feathers nested sooner than others, thus increasing individual fitness.

Delhey, K, et al. 2003. Cosmetic coloration in birds: Occurrence, function, and evolution. American Naturalist. 169(1):145-158.  This study looks at cosmetic coloration in bird species. Cosmetic coloration is a type of sexual signal where the plumage of a bird is enhanced. There are several different ways in which the plumage can be influenced by cosmetic coloration. The first way is having the cosmetics being made by the animal itself, such as by uropygial and skin secretions or feather powder. The second way is from the environment with the bird getting the cosmetic from soil. These cosmetics are used in sexual signaling and they affect the fitness of the bird. This article looks at the costs and mechanisms of cosmetic coloration and their evolutionary basis.

Guilford, D, Dawkins, MS. (1991). Receiver Psychology and the Evolution of Animal Signals. Animal Behavior. 42(1): 1-14.  Animals have many different signaling mechanisms to attract a mate. These signals have two different design components, strategic design and efficacy. Strategic design deals with how a signal has been “made” via natural selection and how the signal works to attract a mate. Efficacy is how the signal is used to get information across to the receiver. This article argues how an important evolutionary force on the signal is the psychology of the receiver and there are three aspects to receiver psychology. These three aspects are powerful selective forces on what the signal is.

Zahavi, A. (1975). Mate Selection- Selection for a Handicap. Journal of Theoretical Biology. 53(1):205-214.  Mate preference often selects for features that can be a hindrance to the animal. Often, the size of features shows quality of the animal and thus affects mate choice. This article looks how these features that seem to be a problem for animals have actually been selected for, and why those traits were selected for and passed on in the population. Also, the article looks at how these knowing that these traits are a hindrance can lead finding answers to certain evolutionary questions

Thomas, DB. (2014). Ancient origins and multiple appearances of carotenoid-pigmented feathers in birds. Proceedings of the Royal Society B Biological Sciences. 281(1788).  This article looks at the lineage of carotenoid pigments in very diverse groups of birds. Using liquid chromatography carotenoid presence was tested and evaluated to follow the evolution of these pigments. Researchers found that there were 13 independent origins of the carotenoid pigment which suggests that there are varying evolutionary forces that selection for these pigments and suggest that these pigments are beneficial to birds.

Ways in which the article can be improved 1.	In the “female choice” section of the page, I think that it would be helpful to add how there are two different components to how these signals were developed. First, there is the design component and then efficacy. I think it would be helpful to add this because it would illustrate that these traits that increase the fitness of the animal do not just randomly happen and that there is a reason why these traits have stuck around. 2.	Under the “visual signaling” heading, I would add the information about cosmetic coloration in flamingos. I would add how during mating season flamingos have an increase in preen oil formation which leads to an increase in the brightness of flamingos feathers, which makes them more appealing to females and increase the males fitness. 3.	Under the “visual signaling” heading, I would talk about widow birds and how they have extremely long tail feathers that affect their fitness and the length of these feathers helps the female select her mate. These long tail feathers are a hindrance to the bird but evolutionary forces have selected for the long tail feathers. “Cosmetic coloration is another mechanism by which male birds use to try to attract a mate. Cosmetic coloration involves brightening of a birds feathers, thus making it more attractive to females.” Amat, JA, et.al. 2010. Greater flamingos Phoenicopterus roseus use uropygial secretions as make-up. Behavioral Ecology and Sociobiology. 65(4): 665-673. https://en.wikipedia.org/wiki/Sexual_selection_in_birds

Final Draft Cosmetic Coloration: Signaling Applications and Mate Choice in Birds

Sexual selection is a mechanism by which natural selection and evolution can occur. Sexual selection involves male or female choice when it comes to choosing a mate. There are two modalities by which sexual selection occurs, intrasexual selection which is competition among one sex (usually males) for mates and the second modality is intersexual selection by which one sex (usually females) makes the choice of who to mate with. Birds are a common group of animals used to study intersexual selection because birds have many ritual, displays, and mechanisms by which females choose a mate. One way that females choose a mate is by the appearance of the male. Male appearance sends a signal to the females that the male is a good or bad choice in mate. These signals will then tell the female whether or not she should choose that male to share her genetic information with. One way that males make themselves more desirable to females, thus increasing their chances of finding a mate, is through cosmetic coloration. Cosmetic coloration is color modifications that are either actively applied by a bird or are secreted onto the feathers of a bird that cause a change in the appearance and texture of mature feathers (Delhey, K, et al. 2003). These alterations are then used as a signaling mechanism to females that can increase the likelihood that those males with altered feathers will be selected as a mate. This bias in mate choice can then drive natural selection to favor males that have the best cosmetic coloration. First, it is important to understand how signaling and communication between animals operates. Signals work to communicate a certain idea to the receiver of the signal. In many cases, the signal is meant to communicate whether a mate is fit or unfit for reproduction. There are two different components to the design of a signal (Guilford and Dawkins 1991). The two components are content of the signal and the signals efficacy. The content of the signal deals with what information is being processed and efficacy is defined as the effectiveness with which information is transmitted and received. Efficacy is contingent on the information being detected by the sensory organs and then that information being associated with other events. For coloration preference in birds, the brightness of the feathers would be what reaches the sensory organs of the female and that information is then associated with how a mate is chosen. If a female bird mates with a male that has drab feather coloring and then her young are weak and have low fitness, the drab feather coloration will be associated with weak young. As a result, upon the females next mating, she will not select a male with poor coloring, and will instead look for a mate with more vibrant coloration. The vibrant coloration will better attract the receiver’s eye and will increase an attraction response (Guilford and Dawkins 1991). That attraction response will lead to the female mating with the male. This selection by the female is an example of intersexual selection and can lead to sexual selection by which females select mates with brighter feathers, so males with drab feathers will have a lower fitness and will be selected against. Birds have other specific ways of communicating to other birds. The complexity of the signals that birds send to one another is a common feature of the communication systems (Rowe and Skelhorn 2004). One way that complexity can be conveyed is in the patterning of a colorful signal. The more complex the pattern, the more salient the signal is to the receiver. One study looked at California quail and found that the combination of multiple ornamentations on males explained the variation in mate choice by females (Rowe and Skelhorn 2004). The plumage ornamentations indicated a level of complexity to the females and this level of complexity was then used by the females to select a mate. This goes along with the idea of efficacy that was previously described because the plumage ornamentations deliver an effective signal to the females about the traits that males have that the female would find desirable. The handicap principle explains a last mode of signaling. The handicap principle suggests that some traits that develop through mate preference will impose a handicap on the individual for whom they have been selected (Zahavi 1975). The handicaps are useful in selecting a mate because they serve as markers for the quality of the mate. This type of handicap is seen in birds that have large plumages such as peacocks, which use their huge plumages to attract peahens. The handicap principle leads to the question of the cost of signaling to the individual (Guilford and Dawkins 1991). These great plumages that are seen in some birds are good at communicating the fitness of the bird but they can also hinder the bird in day-to-day functions. Also, these huge plumages come at a cost because they make the bird more visible to predators, which could cause a decrease in fitness. This mismatch between the good signal and the cost of the signal is a form of sensory bias or receiver bias. Receiver bias is when signals evolve to match the preference of the receiver. In the case of the peacocks, the peahen has a preference that bias’ her to prefer the huge plumages, so these feather adornments have evolved to match up with the peahens preferences because they will incur the greatest fitness payoff to the male. This sensory bias has lead to what is called runaway sexual selection whereby females select for more exaggerated signals because they have a greater efficacy (Tazzyman 2014). These signals or characters may be chosen for no apparent reason and may not indicate any difference in fitness between males, but the female has chosen for the trait anyway because she prefers this. This preference can lead to selection for males that have that trait. An example of runaway sexual selection is in tail length in widow birds. Females have selected for the tail length in males to be very exaggerated but the tail length tells nothing about the true fitness of the individual. All of these sensory signals show how signals can affect mate choice and drive sexual selection. Sensory signaling has lead to a new form of intersexual selection, which was previously introduced as cosmetic coloration. To reiterate, cosmetic coloration is color modification of the feathers that makes them appear brighter or have a different texture. Cosmetic coloration has two different types. The first is a type is when substances are produced by the bird itself such as uropygial gland secretions, skin secretions, and powder. The second kind are substances that the bird acquires from the environment such as soil (Delhey, et al 2003). The first type of coloration, whereby the animal produces the substances for coloration, is directed by secretions of the uropygial gland. This gland secretes waxes and oils that make feathers appear glossier which causes an increase in brightness. The feathers coated with the preen oils look brighter and the degree to which the plumage was glossy was a way in which mates could determine the diet or overall health of the individual. The uropygial gland also can change the shape of the reflected light off the feathers, which alters what wavelengths of light are reflected. The secretions of the gland illustrate how this coloration is cosmetic. For example, species of hornbill produce colored gland secretions that they apply to their plumage, thereby changing the color of their feathers. Only sexually mature birds develop the coloration, which would lead to the inference that these secretions have something to do with the sexual activity of the birds. Another example is in the greater flamingo Phoenicopterus roseus. This study found that the flamingo applied these carotenoid rich secretions from the uropygial gland on its plumage and the resulting cosmetic coloration may influence mate choice (Amat, et.al 2010). This data is supported by the findings that application of the oils was more frequent during periods where the flamingos were displaying for mates and the presence of the cosmetic coloration decreased after egg hatching, indicating that the coloration has the function of finding mates but it is not of use after a mate has been found. A last example is in the house finch where they found that preen waxes on feathers acted as cosmetics and that the waxes increased the signal content of feather traits (Lopez-Rull, et al 2010). The signal content correlated to the condition of the individual and increased the signaling value to mates, and therefore affected mate choice, implying that cosmetic coloration has some effect on sexual selection. These carotenoid pigments have been seen in multiple families of birds and have been traced back Cenozoic era, indicating that these pigments have a strong evolutionary benefit to the individual (Thomas 2014). The second type of coloration that also involves gland secretions is with powder feathers (Delhey, et al 2003). Powder feathers are modified feathers that disintegrate into a fine powder. These powder feathers are found on pigeons, parrots, and herons. Herons provide a great example of how cosmetic coloration is related to mate choice and sexual selection. In the whistling heron, they develop a yellowish color on their neck, stomach, and tail due to the powder feathers. The coloration due to the powder is more intense during breeding season. In bustards, males use a red powder during courtship displays to attract mates and then the powder fades after the display. These examples show how these modifications to feathers can affect mate choice. The last kind of cosmetic coloration is when external substances are used to color the feathers, such as dirt. In bearded vultures, individuals will bath in mud and the degree to which the mud stains the feathers is seen as a sign of dominance. This sign of dominance could then affect mate choice. Birds rely on communication systems and their corresponding signals to ensure that a fit mate is chosen. The efficacy of the signal and the complexity of signals all allow females to choose the bet mate. The power of female choice often leads to development of certain characteristics in males that are desirable. In this case, cosmetic coloration was investigated to see how changes to feathers affected mate choice. It was found that by the mechanism of cosmetic coloration, many species of birds have increased the efficacy of their signaling to mates, thus increasing their breeding opportunities. This demonstrates how cosmetic coloration can be a cause of sexual selection in birds. References Amat, JA, et.al. 2010. Greater flamingos Phoenicopterus roseus use uropygial secretions as make-up. Behavioral Ecology and Sociobiology. 65(4): 665-673. Delhey, K, et al. 2003. Cosmetic coloration in birds: Occurrence, function, and evolution. American Naturalist. 169(1):145-158. Guilford, D, Dawkins, MS. (1991). Receiver Psychology and the Evolution of Animal Signals. Animal Behavior. 42(1): 1-14. Lopez-Rull, I, et al. 2010. Cosmetic Enhancement of Signal Coloration: Experimental Evidence in the House Finch. Behavioral Ecology. 21(4):781-787. Rowe, C, Skelhorn J. 2004. Avian Psychology and Communication. Proceedings of the Royal Society B Biological Sciences. 271(1547):1435-1442. Tazzyman, SJ, et al. 2014. Signaling Efficacy Drives the Evolution of Larger Sexual Ornaments by Sexual Selection. Evolution. 68(1):216-229. Thomas, DB. (2014). Ancient origins and multiple appearances of carotenoid-pigmented feathers in birds. Proceedings of the Royal Society B Biological Sciences. 281(1788). Zahavi, A. (1975). Mate Selection- Selection for a Handicap. Journal of Theoretical Biology. 53(1):205-214.

Edit to a Page https://en.wikipedia.org/wiki/Sexual_selection_in_birds Cosmetic coloration is another mechanism by which male birds use to try to attract a mate. Cosmetic coloration involves brightening of a birds feathers, thus making it more attractive to females. Cosmetic coloration has two different types. The first is a type is when substances are produced by the bird itself such as uropygial gland secretions, skin secretions, and powder. The second kind are substances that the bird acquires from the environment such as soil. The first type of coloration, whereby the animal produces the substances for coloration, is directed by secretions of the uropygial gland. This gland secretes waxes and oils that make feathers appear glossier which causes an increase in brightness. The feathers coated with the preen oils look brighter and the degree to which the plumage was glossy was a way in which mates could determine the diet or overall health of the individual. The uropygial gland also can change the shape of the reflected light off the feathers, which alters what wavelengths of light are reflected. The secretions of the gland illustrate how this coloration is cosmetic. For example, species of hornbill produce colored gland secretions that they apply to their plumage, thereby changing the color of their feathers. Only sexually mature birds develop the coloration, which would lead to the inference that these secretions have something to do with the sexual activity of the birds. Another example is in the greater flamingo Phoenicopterus roseus. This study found that the flamingo applied these carotenoid rich secretions from the uropygial gland on its plumage and the resulting cosmetic coloration may influence mate choice. This data is supported by the findings that application of the oils was more frequent during periods where the flamingos were displaying for mates and the presence of the cosmetic coloration decreased after egg hatching, indicating that the coloration has the function of finding mates but it is not of use after a mate has been found. A last example is in the house finch where they found that preen waxes on feathers acted as cosmetics and that the waxes increased the signal content of feather traits. The signal content correlated to the condition of the individual and increased the signaling value to mates, and therefore affected mate choice, implying that cosmetic coloration has some effect on sexual selection. These carotenoid pigments have been seen in multiple families of birds and have been traced back Cenozoic era, indicating that these pigments have a strong evolutionary benefit to the individual. The second type of coloration that also involves gland secretions is with powder feathers. Powder feathers are modified feathers that disintegrate into a fine powder. These powder feathers are found on pigeons, parrots, and herons. Herons provide a great example of how cosmetic coloration is related to mate choice and sexual selection. In the whistling heron, they develop a yellowish color on their neck, stomach, and tail due to the powder feathers. The coloration due to the powder is more intense during breeding season. In bustards, males use a red powder during courtship displays to attract mates and then the powder fades after the display. These examples show how these modifications to feathers can affect mate choice. The last kind of cosmetic coloration is when external substances are used to color the feathers, such as dirt. In bearded vultures, individuals will bath in mud and the degree to which the mud stains the feathers is seen as a sign of dominance. This sign of dominance could then affect mate choice.