scholarly journals The fitness consequences of honesty: under-signalers have a survival advantage in song sparrows

2015 ◽  
Author(s):  
Çağlar Akçay ◽  
S. Elizabeth Campbell ◽  
Michael D. Beecher
Keyword(s):  
Evolutionary Biology ◽  
Survival Advantage ◽  
Future Research ◽  
Major Question ◽  
Song Sparrows ◽  
Soft Song ◽  
High Aggression ◽  
Close Range ◽  
Low Levels ◽  
Reliable Signaling

How honest or reliable signaling can evolve and be maintained has been a major question in evolutionary biology. The question is especially puzzling for a particular class of signals used in aggressive interactions: threat signals. Here we report a study on song sparrows (Melospiza melodia) in which we assayed males with playbacks on their territories to quantify their aggressiveness (flights and close proximity) and aggressive signaling levels (rates of soft song, a close range signal reliably predicting attack) and asked whether these traits affect individuals’ survival on territory. We found that the effect of aggressive signaling via soft song interacted with aggressive behaviors such that there was a negative correlational selection: among males with low aggression, those males that signaled at higher levels (over-signalers) had higher survival whereas among males with high aggression those that signaled at low levels (under-signalers) survived longer. In other words, males who deviate from reliable signaling have a survival advantage. These results, along with previous research that suggested most of the deviation from reliable signaling in this system is in the form of under-signaling (high aggression males signaling at low levels) pose a puzzle for future research on how this reliable signaling system is maintained.

scholarly journals The fitness consequences of honesty: under-signalers have a survival advantage in song sparrows

2015 ◽  
Author(s):  
Çağlar Akçay ◽  
S. Elizabeth Campbell ◽  
Michael D. Beecher
Keyword(s):  
Evolutionary Biology ◽  
Survival Advantage ◽  
Future Research ◽  
Major Question ◽  
Song Sparrows ◽  
Soft Song ◽  
High Aggression ◽  
Close Range ◽  
Low Levels ◽  
Reliable Signaling

How honest or reliable signaling can evolve and be maintained has been a major question in evolutionary biology. The question is especially puzzling for a particular class of signals used in aggressive interactions: threat signals. Here we report a study on song sparrows (Melospiza melodia) in which we assayed males with playbacks on their territories to quantify their aggressiveness (flights and close proximity) and aggressive signaling levels (rates of soft song, a close range signal reliably predicting attack) and asked whether these traits affect individuals’ survival on territory. We found that the effect of aggressive signaling via soft song interacted with aggressive behaviors such that there was a negative correlational selection: among males with low aggression, those males that signaled at higher levels (over-signalers) had higher survival whereas among males with high aggression those that signaled at low levels (under-signalers) survived longer. In other words, males who deviate from reliable signaling have a survival advantage. These results, along with previous research that suggested most of the deviation from reliable signaling in this system is in the form of under-signaling (high aggression males signaling at low levels) pose a puzzle for future research on how this reliable signaling system is maintained.

scholarly journals Aggressiveness, reliable signaling and survival in a wild songbird

2015 ◽  
Author(s):  
Çağlar Akçay ◽  
S. Elizabeth Campbell ◽  
Michael D. Beecher
Keyword(s):  
Evolutionary Biology ◽  
Future Research ◽  
Major Question ◽  
Song Sparrows ◽  
Soft Song ◽  
Close Proximity ◽  
High Aggression ◽  
Close Range ◽  
Low Levels ◽  
Reliable Signaling

The evolution and maintenance of honest or reliable signaling has been a major question in evolutionary biology. The question is especially puzzling for a particular class of signals used in aggressive interactions: threat signals. Here we report a study on song sparrows (Melospiza melodia) in which we assayed males with playbacks in their territories to quantify their aggressiveness (flights, and close proximity) and aggressive signaling levels (rates of soft song, a close range signal reliably predicting attack) and asked whether these traits affect individuals’ survival on territory. We found that the effect of aggressive signaling via soft song interacted with aggressive behaviors such that there was a negative correlational selection: among males with low aggression, those males that signaled at higher levels (over-signalers) had higher survival whereas among males with high aggression those that signaled at low levels (under-signalers) survived longer. In other words, males who deviate from reliable signaling have a survival advantage. These results, along with previous research that suggested most of the deviation from reliable signaling in this system is in the form of under-signaling (high aggression males signaling at low levels) pose a puzzle for future research on how this reliable signaling system is maintained.

scholarly journals Aggressiveness, reliable signaling and survival in a wild songbird

2015 ◽  
Author(s):  
Çağlar Akçay ◽  
S. Elizabeth Campbell ◽  
Michael D. Beecher
Keyword(s):  
Evolutionary Biology ◽  
Melospiza Melodia ◽  
Honest Signaling ◽  
Major Question ◽  
Aggressive Interactions ◽  
Song Sparrows ◽  
Fitness Consequences ◽  
High Aggression ◽  
Reliable Signaling

The evolution and maintenance of honest or reliable signaling has been a major question in evolutionary biology. The question is especially puzzling for a particular class of signals used in aggressive interactions: threat signals. Here we report a study on song sparrows (Melospiza melodia) in which we assayed males with playbacks in their territories to quantify their aggressiveness and aggressive signaling levels and asked whether these affect their survival on territory. We found that the effect on survival of residual signaling (signaling above or below the level predicted by their aggressiveness) depended on aggression levels such that among males with low aggression, those with higher residual signaling scores had higher survival. The residual signaling did not have a strong effect among high aggression males. Aggressiveness by itself did not have an effect on survival. These results present a first step in understanding the fitness consequences of honest signaling in aggressive contexts.

scholarly journals Are signals of aggressive intent less honest in urban habitats?

2019 ◽  
Author(s):  
Çağlar Akçay ◽  
Michelle L Beck ◽  
Kendra B Sewall
Keyword(s):  
Acoustic Noise ◽  
Visual Signals ◽  
Acoustic Properties ◽  
Urban Habitats ◽  
Urban Birds ◽  
Urban Noise ◽  
Song Sparrows ◽  
Soft Song ◽  
Close Range ◽  
Low Amplitude

Abstract How anthropogenic change affects animal social behavior, including communication is an important question. Urban noise often drives shifts in acoustic properties of signals but the consequences of noise for the honesty of signals—that is, how well they predict signaler behavior—is unclear. Here we examine whether honesty of aggressive signaling is compromised in male urban song sparrows (Melospiza melodia). Song sparrows have two honest close-range signals: the low amplitude soft songs (an acoustic signal) and wing waves (a visual signal), but whether the honesty of these signals is affected by urbanization has not been examined. If soft songs are less effective in urban noise, we predict that they should predict attacks less reliably in urban habitats compared to rural habitats. We confirmed earlier findings that urban birds were more aggressive than rural birds and found that acoustic noise was higher in urban habitats. Urban birds still sang more soft songs than rural birds. High rates of soft songs and low rates of loud songs predicted attacks in both habitats. Thus, while urbanization has a significant effect on aggressive behaviors, it might have a limited effect on the overall honesty of aggressive signals in song sparrows. We also found evidence for a multimodal shift: urban birds tended to give proportionally more wing waves than soft songs than rural birds, although whether that shift is due to noise-dependent plasticity is unclear. These findings encourage further experimental study of the specific variables that are responsible for behavioral change due to urbanization. Soft song, the low amplitude songs given in close range interactions, is an honest threat signal in urban song sparrows. Given its low amplitude, soft songs may be a less effective signal in noisy urban habitats. However, we found that soft song remained an honest signal predicting attack in urban habitats. We also found that birds may use more visual signals (rapid fluttering of wings) in urban habitats to avoid masking from acoustic noise.

Risk assessment of waterborne protozoa: current status and future trends

Parasitology ◽  
1999 ◽  
Vol 117 (7) ◽  
pp. 205-212 ◽  
Author(s):  
C. J. GIBSON ◽  
C. N. HAAS ◽  
J. B. ROSE
Keyword(s):  
Risk Assessment ◽  
Management Practices ◽  
Assessment Methods ◽  
Detection Methods ◽  
Current Status ◽  
Future Research ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Chemical Risk Assessment ◽  
Low Levels

Throughout the past decade much research has been directed towards identifying the occurrence, epidemiology, and risks associated with waterborne protozoa. While outbreaks are continually documented, sporadic cases of disease associated with exposure to low levels of waterborne protozoa are of increasing concern. Current methodologies may not be sensitive enough to define these low levels of disease. However, risk assessment methods may be utilised to address these low level contamination events. The purpose of this article is to provide an introduction to microbial risk assessment for waterborne protozoa. Risk assessment is a useful tool for evaluating relative risks and can be used for development of policies to decrease risks. Numerous studies have been published on risk assessment methods for pathogenic protozoa including Cryptosporidium and Giardia. One common notion prevails: microbial risk assessment presents interesting complications to the traditional chemical risk assessment paradigm. Single microbial exposures (non-threshold) are capable of causing symptomatic illness unlike traditional chemical exposures, which require a threshold to be reached. Due to the lack of efficient recovery and detection methods for protozoa, we may be underestimating the occurrence, concentration and distribution of these pathogenic micro-organisms. To better utilize the tool of microbial risk assessment for risk management practices, future research should focus in the area of exposure assessment.

Education and Anti-Immigration Attitudes: Evidence from Compulsory Schooling Reforms across Western Europe

2018 ◽  
Vol 113 (1) ◽  
pp. 254-263 ◽  
Author(s):  
CHARLOTTE CAVAILLE ◽  
JOHN MARSHALL
Keyword(s):  
Secondary School ◽  
Western Europe ◽  
Future Research ◽  
Compulsory Schooling ◽  
Far Right ◽  
Secondary Schooling ◽  
Low Levels ◽  
Immigration Attitudes ◽  
Post War

Low levels of education are a powerful predictor of anti-immigration sentiment. However, there is little consensus on the interpretation of this correlation: is it causal or is it an artifact of selection bias? We address this question by exploiting six major compulsory schooling reforms in five Western European countries—Denmark, France, Great Britain, the Netherlands, and Sweden—that have recently experienced politically influential anti-immigration movements. On average, we find that compelling students to remain in secondary school for at least an additional year decreases anti-immigration attitudes later in life. Instrumental variable estimates demonstrate that, among such compliers, an additional year of secondary schooling substantially reduces the probability of opposing immigration, believing that immigration erodes a country’s quality of life, and feeling close to far-right anti-immigration parties. These results suggest that rising post-war educational attainment has mitigated the rise of anti-immigration movements. We discuss the mechanisms and implications for future research examining anti-immigration sentiment.

scholarly journals Molecular Evolution of Calcium Signaling and Transport in Plant Adaptation to Abiotic Stress

2021 ◽  
Vol 22 (22) ◽  
pp. 12308
Author(s):  
Tao Tong ◽  
Qi Li ◽  
Wei Jiang ◽  
Guang Chen ◽  
Dawei Xue ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
Calcium Signaling ◽  
Stress Responses ◽  
Evolutionary Biology ◽  
Regulatory Networks ◽  
Cascade Reactions ◽  
Future Research ◽  
Spatiotemporal Pattern ◽  
Green Plants ◽  
Signaling Components

Adaptation to unfavorable abiotic stresses is one of the key processes in the evolution of plants. Calcium (Ca2+) signaling is characterized by the spatiotemporal pattern of Ca2+ distribution and the activities of multi-domain proteins in integrating environmental stimuli and cellular responses, which are crucial early events in abiotic stress responses in plants. However, a comprehensive summary and explanation for evolutionary and functional synergies in Ca2+ signaling remains elusive in green plants. We review mechanisms of Ca2+ membrane transporters and intracellular Ca2+ sensors with evolutionary imprinting and structural clues. These may provide molecular and bioinformatics insights for the functional analysis of some non-model species in the evolutionarily important green plant lineages. We summarize the chronological order, spatial location, and characteristics of Ca2+ functional proteins. Furthermore, we highlight the integral functions of calcium-signaling components in various nodes of the Ca2+ signaling pathway through conserved or variant evolutionary processes. These ultimately bridge the Ca2+ cascade reactions into regulatory networks, particularly in the hormonal signaling pathways. In summary, this review provides new perspectives towards a better understanding of the evolution, interaction and integration of Ca2+ signaling components in green plants, which is likely to benefit future research in agriculture, evolutionary biology, ecology and the environment.

Creativity Enhancement

2013 ◽  
pp. 161-168
Author(s):  
Monty McNair ◽  
Caroline Howard ◽  
Indira Guzman ◽  
Paul Watkin
Keyword(s):  
Information Systems ◽  
21St Century ◽  
Low Cost ◽  
Cost Effective ◽  
Future Research ◽  
Creative Performance ◽  
Creativity Training ◽  
Low Levels ◽  
Adaptive Approaches ◽  
Information Systems Personnel

Since the dawn of humanity, creativity has been critical to surmounting the challenges of life. Innovation is particularly essential to survival on every level from an individual solving his/her problems to a world dependent on adaptive approaches to cope with rapidly expanding populations and enormous international tensions. Currently, information systems programs are not fostering the creativity needed to sustain the innovation required to compete in the 21st century marketplace. Educators and researchers need to better understand the effects of creativity training on creative performance to best design programs that meet the needs of information systems personnel and their employers. The results of this study provide evidence that it would be valuable for organizations to experiment with creativity tutorials and recommend that future research be conducted using larger samples of individuals with low levels of creativity. Because the costs of informing people about creativity are low and creativity tutorials can be designed to be easily administered and completed, the authors recommend that a low-cost tutorial would be a cost effective and beneficial strategy for organizations to employ with information systems personnel, especially those who assess themselves as low in creativity.

scholarly journals Determination of Thermal Comfort in Indoor Sport Facilities Located in Moderate Environments: An Overview

Atmosphere ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 769 ◽  
Author(s):  
Fabio Fantozzi ◽  
Giulia Lamberti
Keyword(s):  
Thermal Comfort ◽  
Thermal Environment ◽  
Thermal Sensation ◽  
Future Research ◽  
Indoor Environmental Quality ◽  
Indoor Environments ◽  
Major Question ◽  
Sport Practice ◽  
Sport Facilities

In previous years, providing comfort in indoor environments has become a major question for researchers. Thus, indoor environmental quality (IEQ)—concerning the aspects of air quality, thermal comfort, visual and acoustical quality—assumed a crucial role. Considering sport facilities, the evaluation of the thermal environment is one of the main issues that should be faced, as it may interfere with athletes’ performance and health. Thus, the necessity of a review comprehending the existing knowledge regarding the evaluation of the thermal environment and its application to sport facilities becomes increasingly relevant. This paper has the purpose to consolidate the aspects related to thermal comfort and their application to sport practice, through a deep study concerning the engineering, physiological, and psychological approaches to thermal comfort, a review of the main standards on the topic and an analysis of the methodologies and the models used by researchers to determine the thermal sensation of sport facilities’ occupants. Therefore, this review provides the basis for future research on the determination of thermal comfort in indoor sport facilities located in moderate environments.

Acoustics of the mountain pine beetle (Dendroctonus ponderosae) (Curculionidae, Scolytinae): sonic, ultrasonic, and vibration characteristics

2013 ◽  
Vol 91 (4) ◽  
pp. 235-244 ◽  
Author(s):  
A.J. Fleming ◽  
A.A. Lindeman ◽  
A.L. Carroll ◽  
J.E. Yack
Keyword(s):  
Bark Beetles ◽  
Mountain Pine Beetle ◽  
Dendroctonus Ponderosae ◽  
Laser Doppler Vibrometer ◽  
Future Research ◽  
Acoustic Signaling ◽  
Mountain Pine ◽  
Pine Beetle ◽  
Close Range ◽  
Low Amplitude

Acoustic signaling is widespread in bark beetles (Scolytinae), although little is known about the physical characteristics of signals, how they are transmitted, and how they differ among behavioural contexts. Signals were studied in the male mountain pine beetle (Dendroctonus ponderosae Hopkins, 1902) during stress, male–female, and male–male interactions. Sounds are broadband with significant energy in the ultrasound (peaks between 15 and 26 kHz) and low amplitude (55 and 47 dB SPL at 2 and 4 cm, respectively), indicating that signaling functions at close range. Signal trains vary among contexts primarily in the proportions of chirp types. Chirps were categorized as being simple or interrupted, with the former having significantly lower tooth strike rates and shorter chirp durations. Stress chirps are predominantly simple with characteristics resembling other insect disturbance signals. Male–female interactions begin with the male producing predominantly interrupted chirps prior to gallery entrance, followed by simple chirps. Male–male (rivalry) chirps are predominantly simple, with evidence of antiphonal calling. Substrate-borne vibrations were detectable with a laser-doppler vibrometer at short distances (1–3 cm), suggesting that sensory organs could be tuned to either air or substrate-borne vibrations. These results have important implications for future research on the function and reception of acoustic signals in bark beetles.

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