Tandem evolution of diet and chemosensory responses in snakes

2008 ◽  
Vol 29 (3) ◽  
pp. 393-398 ◽  
Author(s):  
William Cooper

Abstract Adaptations to foraging requirements have molded sensory capacities of animals in intriguing and sometimes spectacular ways, including evolution of echolocation by bats and infrared detection by pitvipers, as well as of location of prey using lingually sampled chemical cues by actively foraging lizards. Among snakes, specialized diets and geographic differences in diets have evolved many times. Because snakes identify prey by vomerolfactory analysis of chemicals sampled by tongue-flicking, it may be predicted that responsiveness to lingually sampled chemical cues corresponds to diet: It should be much stronger to prey included in than excluded from specialized diets and should covary with geographic dietary differences in prey generalists. Breeding studies in Thamnophis elegans showed that greater responsiveness to local prey in populations having geographically variable diets has a heritable component. Whether strong chemosensory response evolves to match current diet has not been established for snakes using the comparative method. For all paired comparisons of dietary change now available, chemosensory behavior changed so that strongest responses were limited to cues from the current prey. Because diets were specialized and snakes were ingestively naive hatchlings in almost all comparisons, the basis for observed relationships is innate rather than experiential. Snake chemosensory responses have evolved to match current diets.

2020 ◽  
Author(s):  
Jenna Gorlick ◽  
Claire Gorman ◽  
Heidi M. Weeks ◽  
Arielle Pearlman ◽  
Natasha Schvey ◽  
...  

Background: Parents of children with high weight are often the target of blame and shaming. However, this form of stigma, termed weight stigma by association, is poorly understood.Objective: To investigate the sources, forms, and impacts of weight stigma by association among mothers of children with overweight or obesity. Methods: Mothers of 5 to 16-year-old children (N=34; 54% non-Hispanic White) participated in semi-structured interviews. A coding scheme was developed using the constant comparative method and reliably applied to interview transcripts. Mothers’ self-reported sociodemographic information, and height and weight were measured.Results: Family members were a common source of negative comments to parents about children’s weight; these comments were often critical of mothers’ parenting and caused hurt feelings and family estrangement. Many mothers also reported negative feelings about their children’s physicians due to interactions about their children’s weight. Almost all mothers expressed guilt and sadness for not parenting differently; many internalized beliefs that they were bad parents because of their children’s weight. Conclusion: Mothers of children with overweight and obesity are frequently the target of weight stigma by association. Additional research is needed to elucidate the impacts of this form of stigma on parents’ health, the parent/child relationship, and children’s health.


2012 ◽  
Vol 58 (4) ◽  
pp. 549-555 ◽  
Author(s):  
Anthony J. Saviola ◽  
David Chiszar ◽  
Stephen P. Mackessy

Abstract Snakes often have specialized diets that undergo a shift from one prey type to another depending on the life stage of the snake. Crotalus viridis viridis (prairie rattlesnake) takes different prey at different life stages, and neonates typically prey on ectotherms, while adults feed almost entirely on small endotherms. We hypothesized that elevated rates of tongue flicking to chemical stimuli should correlate with particular prey consumed, and that this response shifts from one prey type to another as individuals age. To examine if an ontogenetic shift in response to chemical cues occurred, we recorded the rate of tongue flicking for 25 neonate, 20 subadult, and 20 adult (average SVL = 280.9, 552, 789.5 mm, respectively) wild-caught C. v. viridis to chemical stimuli presented on a cotton-tipped applicator; water-soluble cues from two ectotherms (prairie lizard, Sceloporus undulatus, and house gecko, Hemidactylus frenatus), two endotherms (deer mouse, Peromyscus maniculatus and lab mouse, Mus musculus), and water controls were used. Neonates tongue flicked significantly more to chemical cues of their common prey, S. undulatus, than to all other chemical cues; however, the response to this lizard’s chemical cues decreased in adult rattlesnakes. Subadults tongue flicked with a higher rate of tongue flicking to both S. undulatus and P. maniculatus than to all other treatments, and adults tongue flicked significantly more to P. maniculatus than to all other chemical cues. In addition, all three sub-classes demonstrated a greater response for natural prey chemical cues over chemical stimuli of prey not encountered in the wild (M. musculus and H. frenatus). This shift in chemosensory response correlated with the previously described ontogenetic shifts in C. v. viridis diet. Because many vipers show a similar ontogenetic shift in diet and venom composition, we suggest that this shift in prey cue discrimination is likely a general phenomenon among viperid snakes.


2007 ◽  
Vol 28 (3) ◽  
pp. 413-417 ◽  
Author(s):  
William Cooper

AbstractThe rough green snake Opheodrys aestivus is a dietary specialist on insects and other arthropods. In a laboratory experiment, I tested chemosensory responses to chemical cues from several taxa palatable to other snakes and two control stimuli presented on cotton swabs. The snakes tongue-flicked at significantly higher rates in response to cues from crickets than from any of the other stimuli, and none of the other potential prey types elicited more tongue-flicks than cologne, the control for response to an odorous substance irrelevant to feeding. These findings are consistent with existing data for a few other species of snakes that are prey specialists, suggesting that correlated evolution may occur between diet specialization and chemosensory responsiveness to cues from the specialized prey. Tests of additional species of prey specialists are needed to establish whether this hypothesis is correct.


2002 ◽  
Vol 80 (4) ◽  
pp. 655-663 ◽  
Author(s):  
William E Cooper Jr., ◽  
Janalee P Caldwell ◽  
Laurie J Vitt ◽  
Valentín Pérez-Mellado ◽  
Troy A Baird

Lizards use chemical cues to locate and identify prey and plant food, assess the nutritional quality of food, and detect plant toxins. Among insectivorous lizards, all actively foraging species studied respond strongly to prey chemicals sampled lingually, but ambush foragers do not. Much recent research has been devoted to assessing differential responses to food and nonfood chemicals (i.e., food-chemical discrimination) by omnivorous and herbivorous species and determining whether correlated evolution has occurred between plant diet and plant-chemical discrimination. We conducted experimental studies of food-chemical discrimination by two species of teiid lizards, the omnivorous Cnemidophorus murinus and the actively foraging insectivorous Ameiva ameiva. The omnivore distinguished both prey and plant chemicals from control substances. The insectivore exhibited prey-chemical, but not plant-chemical, discrimination, as indicated by tongue-flicking and biting. A comparative analysis using concentrated-changes tests showed that correlated evolution has occurred between plant consumption and plant-chemical discrimination in a major lizard taxon, Lacertiformes. These results extend and strengthen previous findings of similar correlated evolution to a new group and add to a growing database indicating that omnivorous lizards use chemical cues to assess both prey and plant foods.


Vojno delo ◽  
2021 ◽  
Vol 73 (3) ◽  
pp. 73-87
Author(s):  
Neđo Danilović

The subject of the research in this paper are contemporary aspects of the relation between branches of the state power and the Armed Forces. The general starting hypothesis was: "If the state power holders do not have stable support in economic and political actors of the social structure and do not ensure their interaction with social, political, cultural, information and communications and security system, then the execution of the modern role of the Armed Forces in the political system is difficult." Almost all main analytical and synthetic methods of knowledge have been used in the paper, and the comparative method when it comes to general scientific methods. From the data collection methods the operational method of document content analysis has been used. The paper emphasizes several main findings, first of all, that the Armed Forces and other elements of the defence system in the process of protection of vital social values should be under constant supervision and civilian control of the legitimately elected legislative power, and the executive power should provide conditions, budget and supreme command and through ministerial instructions give guidelines and priorities for the development of the Armed Forces and directly control them. The judicial power sanctions anti-constitutional and illegal actions of the Armed Forces members, as well as other citizens of the society, but also protects the rights and freedoms of those who seek justice.


2007 ◽  
Vol 85 (5) ◽  
pp. 619-625 ◽  
Author(s):  
William E. Cooper, ◽  
Stephen Secor

Squamate reptiles use the lingual–vomeronasal system to identify food using only chemical cues. In lizards, most of which are dietary generalists that consume a wide variety of arthropods and other small animals, correlated evolution has occurred between addition of plants to the diet and responsiveness to plant chemical cues. In snakes, many of which are dietary specialists, several studies have detected differences in response strength among populations that correspond to the importance of prey types in different geographic locations. In one species of Thamnophis Fitzinger, 1843, such variation in responsiveness has been demonstrated to have a genetic basis. We studied tongue-flicking and biting responses to chemical cues from a range of potential prey types by nine ingestively naive hatchlings of the eastern hog-nosed snake ( Heterodon platirhinos Latreille in Sonnini and Latreille, 1801), which is an extreme toad specialist that less frequently eats other anurans. The snakes responded most strongly to chemical cues from the southern toad ( Bufo terrestris (Bonnaterre, 1789)), as indicated by significantly greater tongue-flick rate. Only two individuals bit in response to chemicals cues, both to the toad cues. Elevated tongue-flick rates were also elicited by chemical cues from the green frog ( Rana clamitans Latreille in Sonnini de Manoncourt and Latreille, 1801), but the mean rate for frog cues was less than for toad cues. Responses to other potential prey types did not differ from those of the control stimuli. Our findings are consistent with those of several other investigators in showing close correspondence between the inclusion and importance of dietary items and the intensity of chemosensory investigation in snakes. Studies of diverse dietary specialists are needed to establish the generality of this relationship in snakes and to demonstrate that diet and chemosensory responses to food cues coevolve.


2019 ◽  
Vol 7 ◽  
pp. 150-177
Author(s):  
Oleksandr PAHIRIA

The article examines the activities of the Organization of Ukrainian Nationalists (OUN) and the Ukrainian Insurgent Army (UPA) through the prism of anti-colonialism theory with the application of the historical-comparative method. Despite the obvious influences of fascism and national-socialism on the OUN ideology and program in the 1930s – early 1940s, the Ukrainian nationalist movement typologically is closer to the category of anti-colonial and national liberation rather than fascist movement. The OUN ideology and program had not been static and dynamically evolved from admiring authoritarian and totalitarian models to the democratic turn in 1943. While on all stages of its activities, the organization pursued one strategic goal and tasks – to fight for Ukraine's independence, to overcome the legacy of foreign rule and colonialism, and to establish a nation-state. The OUN and UPA phenomenon was inherent against the backdrop of similar national liberation and anti-colonial movements in Europe, Asia, and Africa. The article comprises a comparative analysis of ideologies, programs, and the political toolbox of various liberation movements that operates from the common comparative base – the stateless status of the respective nations and their desire to exercise their right to self-determination and to liberate from national subjugation. Most of the liberation movements were radical and practiced violence against their political opponents, and almost all developed a rigid internal discipline and hierarchy. At the same time, such typology does not eliminate all controversial issues surrounding Ukrainian nationalists' history, including the involvement of OUN/UPA members in war crimes and crimes against humanity. Keywords: the Organization of Ukrainian Nationalists (OUN), the Ukrainian Insurgent Army (UPA), liberation movements, colonialism, comparative studies


2020 ◽  
Vol 21 (21) ◽  
pp. 83-97
Author(s):  
Jian Liu

Theoretical background. Depending on the choice of the original source underlying the work, all Broadway musicals can be divided into three main types – with the original libretto and plot (“Next to normal” by T. Kitt), based on (or even on the material) of the same name cartoons (E. John’s “The Lion King”, D. Stewart’s and G. Ballard’s “Ghost”) and operas (E. John’s “Aida” after G. Verdi’s opera of the same name, J. Larson’s “Rent” written after “La bohème” by G. Puccini). In the latter group there is a contrasting branching, which can be observed even on the example of the two named musicals. If E. John seeks to preserve the historical correspondence to the epoch depicted in the opera, as well as to embody the conditionally Egyptian oriental color with the help of exotic orchestration, then J. Larson makes a radical modernization of the plot. His radicalism lies not so much in the time distance over which he “transposes” events, as in the “reduction” to naturalistic brutality and nudity of forbidden, but very “painful” in the 90s of the twentieth century topics – drugs, AIDS, same-sex relationships. In comparison with the problems of the musical, G. Puccini’s opera is perceived as a romanticized fairy tale. The social acuity of the musical is closer to the verismo aesthetics than the opera by G. Puccini, and encourages a more thorough analysis of its relationship with the opera prototype. The objective of the article is to reveal the specifics of the metamorphosis of the plot and musical drama of Puccini’s “La bohème” in the musical “Rent” by J. Larson. In accordance with the goal, research methods such as structural and functional are used to identify the components of the composer’s text and their role in the drama of the whole, comparative method to consider selected works in terms of plot interpretation, libretto features, general developing of the drama and musical text. Results of the study. J. Larson’s musical “Rent” demonstrate a free interpretation of G. Puccini’s opera original, with which a number of metamorphoses take place. The first is related to the modernization of the plot, which is transposed from Paris in the mid-nineteenth century to the 90s of the twentieth century and the “lower classes” of New York. The plot is reduced due to the saturation of its topical issues, which reflected the American spirit of the 90’s – AIDS, drug addiction, same-sex relationships. At the same time, the lyricization of drama is carried out, because in the musical J. Larson shows the development of the love affair of three couples. Almost all of them end tragically: Angel dies, Mimi is also on the verge of death. In turn, Joan and Maureen constantly quarrel and reconcile only at the end of the musical. At the same time, the plot outline of the development of Roger and Mimi’s relationship duplicates a similar line of the opera, starting from the scene of their acquaintance and ending with a duet in the finale, where the characters once again confess their love for each other. The key scene is the manifesto of bohemian life, as in the opera, is the scene in a cafe (“La Vie Boheme”, № 23). Musical dramaturgy of “Rent”, in contrast to the plot, is far removed from the operatic original, due to the genre tradition of the musical, which is reflected in the two-act structure, the principle of dramatic “relaxation” in the second act, where the denouement of all plot lines comes, number structure, where musical numbers alternate with conversational dialogues. At the same time, J. Larson strives for the integrity of the musical’s dramaturgy, which is reflected in the “musicalization” of dialogues, which mostly sound with musical accompaniment and flexibly flow into duet-ensemble scenes. The solo numbers, which brings a stop to the action, is mostly replaced by duets that “promote” the action and reveal the development of the characters’ relationships (the key pair has four such duets). Conclusions. All mentioned qualities of the musical “Rent” significantly distinguish the composition of J. Larson from another example of the musical based after the opera – “Aida” by E. John, which allows us to talk about the presence of individual compositional and dramatic solutions, even when working with a similar source. This shows the significant potential of the Broadway musical as a musical-theatrical genre, as opposed to its accusations of commercialism and the assertion of the priority of entertainment, which makes it an interesting and perspective material for research.


1973 ◽  
Vol 27 (3) ◽  
pp. 188-198 ◽  
Author(s):  
Philip L. Hanst ◽  
Allen S. Lefohn ◽  
Bruce W. Gay

Infrared detection of air pollutants has been extended to the parts-per-billion sensitivity range. The increased detection sensitivity results from the use of the scanning Michelson interferometer, cooled solid state detectors, the fast minicomputer, and the multiple pass long path cell. Forming ratios of spectra with the aid of the computer extracts obscure information and minimizes the interferences of atmospheric water and carbon dioxide. Almost all of the significant gaseous pollutants can be measured by the method described, even at concentrations smaller than one part pollutant to one billion parts air.


2000 ◽  
Vol 78 (8) ◽  
pp. 1375-1379 ◽  
Author(s):  
William E Cooper, Jr.

Most iguanian lizards are insectivores that do not use chemical cues sampled by tongue-flicking to identify prey before attacking, but the sole iguanian herbivore previously studied did so. To investigate the effects of a partially herbivorous diet on responses to food chemicals, I conducted an experiment to determine whether the omnivorous bearded dragon (Pogona vitticeps) has a similar ability. Chemical stimuli from crickets and carrots, both preferred foods, and alfalfa sprouts, and deionized water (a nonpreferred food and odorless control, respectively) were presented on cotton-tipped applicators. The lizards responded more strongly to both preferred foods than to the controls, performing more tongue flicks and biting the cotton in a greater number of trials. It is hypothesized that lingually mediated food-chemical discrimination is useful to herbivorous and omnivorous lizards for identifying plant and animal foods and for evaluating the quality of plant foods. The insectivorous ambush foragers ancestral to P. vitticeps could not locate prey by tongue-flicking repeatedly at an ambush post and do not exhibit prey-chemical discrimination. Adding plants to the diet altered the selective milieu because plants approached using visual cues can be evaluated using chemical cues, allowing the evolution of the ability to discriminate between plant-food chemicals. The ability to identify animal prey by tongue-flicking may have evolved through correlated evolution with chemosensory identification of plants or specifically for locating or identifying immobile prey.


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