Sensory cues underlying competitive growth in the clown anemonefish (Amphiprion percula)

2020 ◽  
Vol 181 ◽  
pp. 104276
Author(s):  
Leah Desrochers ◽  
Rebecca Branconi ◽  
E Schlatter ◽  
Brianne Dent ◽  
Peter Buston
2019 ◽  
Vol 15 (2) ◽  
pp. 20180737 ◽  
Author(s):  
Cymone Reed ◽  
Rebecca Branconi ◽  
John Majoris ◽  
Cara Johnson ◽  
Peter Buston

Many animal societies have dominance hierarchies in which social rank is correlated with size. In such societies, the growth and size of individuals can be a strategic response to their social environment: in fishes, individuals may decrease their growth rate to remain small and retain a subordinate position; in mammals, individuals may increase their growth rate to become large and attain a dominant position—a strategy called competitive growth. Here, we investigate whether the clown anemonefish, Amphiprion percula , exhibits competitive growth also. We show that juvenile clownfish paired with a size-matched reproductive rival increase their growth rate and size relative to solitary controls. Remarkably, paired individuals achieved this, despite being provided with the same amount of food as solitary controls. Our results demonstrate that clownfish are able to increase their growth rate in response to social competition. This study adds to the growing body of evidence that the growth of social vertebrates can be a fine-tuned plastic response to their social environment.


2018 ◽  
Vol 23 (6) ◽  
pp. 14-15
Author(s):  
Lee H. Ensalada

Abstract Symptom validity testing (SVT), also known as forced-choice testing, is a means of assessing the validity of sensory and memory deficits, including tactile anesthesias, paresthesias, blindness, color blindness, tunnel vision, blurry vision, and deafness. The common feature among these symptoms is a claimed inability to perceive or remember a sensory signal. SVT comprises two elements: a specific ability is assessed by presenting a large number of items in a multiple-choice format, and then the examinee's performance is compared to the statistical likelihood of success based on chance alone. These tests usually present two alternatives; thus the probability of simply guessing the correct response (equivalent to having no ability at all) is 50%. Thus, scores significantly below chance performance indicate that the sensory cues must have been perceived, but the examinee chose not to report the correct answer—alternative explanations are not apparent. SVT also has the capacity to demonstrate that the examinee performed below the probabilities of chance. Scoring below a norm can be explained by fatigue, evaluation anxiety, inattention, or limited intelligence. Scoring below the probabilities of chance alone most likely indicates deliberate deceptions and is evidence of malingering because it provides strong evidence that the examinee received the sensory cues and denied the perception. Even so, malingering must be evaluated from the total clinical context.


2019 ◽  
Vol 13 (03) ◽  
pp. 139-144
Author(s):  
Michael Hermanussen ◽  
Christiane Scheffler ◽  
Barry Bogin

Zusammenfassung Hintergrund Noch immer gründen heutige Analysen genetischer Zwillings- und Familienstudien auf mathematischen Ansätzen des frühen 20. Jahrhunderts, namentlich von Galton, Pearson und Fisher, und führen zu konventionellen Schätzwerten für die Heritabilität der Körperhöhe zwischen h² = 0,87 und h² = 0,93 bei Männern und zwischen h² = 0,68 und h² = 0,84 bei Frauen. Diese Werte sind wesentlich höher als moderne Schätzungen auf der Basis genomweiter Assoziationsstudien (GWAS), mit denen sich zwischen 12,3 % und 49 % der Körperhöhenvarianz im Erwachsenenalter erklären lassen. Diese so genannte „missing heritability“ gibt Anlass zu Missverständnissen. Diskussion Wir nehmen eine biokulturelle Perspektive ein, um Entwicklungsmerkmale zu verstehen, die nur auf den ersten Blick erblich erscheinen. Innerhalb sozialer Gruppen dient Körpergröße als Signal. Kompetitive Wachstumsstrategien (competitive growth strategies) und strategische Wachstumsanpassungen (strategic growth adjustments) insbesondere im Hinblick auf die Gefahr, aus einer führenden sozialen Rolle verdrängt zu werden (threat of being displaced) sind bei sozialen Säugern beschrieben und spielen sehr wahrscheinlich auch in menschlichen Sozialstrukturen eine wesentliche Rolle. Die Körperhöhe eines Menschen hängt von der Körperhöhe anderer Mitglieder seiner Peer Group ab. Im vergangenen Jahrhundert wurden Körperhöhentrends von bis zu 20 cm in manchen Populationen beobachtet (säkulare Trends). Dies ist Ausdruck von phänotypischer Plastizität und war Galton, Pearson und Fisher unbekannt. Schlussfolgerung Die beschriebene „missing heritability“ für Körperhöhe spiegelt die Diskrepanz zwischen moderner Wissenschaft und überholten Vermengungen von deterministischen und politischen Ideen des frühen 20. Jahrhunderts wider.


1991 ◽  
Vol 23 (4-6) ◽  
pp. 899-905 ◽  
Author(s):  
Y. Matsuzawa ◽  
T. Mino

Activated sludge mixed cultures were cultivated with a glucose containing substrate in order to investigate the relationship between the feeding pattern (continuous or intermittent feeding) and the glycogen reservation capacity of activated sludge. An experimental method to measure the maximum capacity of glycogen reservation in the sludge was developed. Sludge with higher glycogen reservation capacity has an ability to synthesize glycogen faster, which ensures the higher glucose uptake. Therefore, sludge which has high glycogen reservation capacity becomes predominant in intermittently fed reactors. When the feeding pattern was changed from continuous feeding to intermittent feeding, a filamentous bacterium, Type 1701, started to decrease and a gram positive tetrad coccus became predominant. When the feeding pattern was returned to continuous feeding, Type 1701 re-appeared. Type 1701 has lower glycogen reservation capacity than the tetrad coccus. Therefore, the former cannot dominate over the latter in intermittently fed reactors.


1995 ◽  
Vol 32 (4) ◽  
pp. 77-88 ◽  
Author(s):  
H. Horn ◽  
D. Uhlmann

Since 1975, different patterns of the growth of Fragilaria and Cyanobacteria in the mid or late summer have been observed in the Saidenbach Reservoir. In most of the years, there was a mutual exclusion of mass growths of these two groups. High yields of Fragilaria caused low yields of blue-greens and vice versa. In the first years, Fragilaria was always the first to achieve a mass growth, followed by the Cyanobacteria. Then, in the last years, the blue-greens were succeeded by Fragilaria. Only in some years, there was a large and simultaneous growth of both groups. It has been shown, that the supply of silicon and phosphorus immediately before controlled the pattern of succession in the midsummer period. Mostly, the Si:P ratio was the regulating factor, but there were also years in which the absolute concentration level of these two nutrients were either non-limiting high or below the minimum resource concentration necessary to compensate for the losses. In these cases, the Si:P ratio lost its controlling function. Other influencing factors are discussed, in particular the effect of turbulent mixing. The special nutrient conditions in the midsummer were not only determined by the external load but also by the Si depletion during the spring mass development of diatoms other than Fragilaria, which mostly is physically controlled. Therefore, the succession pattern in the midsummer is sensitive to the meteorological conditions to a large extent.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Caitlin S. Mallory ◽  
Kiah Hardcastle ◽  
Malcolm G. Campbell ◽  
Alexander Attinger ◽  
Isabel I. C. Low ◽  
...  

AbstractNeural circuits generate representations of the external world from multiple information streams. The navigation system provides an exceptional lens through which we may gain insights about how such computations are implemented. Neural circuits in the medial temporal lobe construct a map-like representation of space that supports navigation. This computation integrates multiple sensory cues, and, in addition, is thought to require cues related to the individual’s movement through the environment. Here, we identify multiple self-motion signals, related to the position and velocity of the head and eyes, encoded by neurons in a key node of the navigation circuitry of mice, the medial entorhinal cortex (MEC). The representation of these signals is highly integrated with other cues in individual neurons. Such information could be used to compute the allocentric location of landmarks from visual cues and to generate internal representations of space.


Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 84
Author(s):  
Xiaohong Wang ◽  
Zhipeng Chen ◽  
Duo Dong ◽  
Dongdong Zhu ◽  
Hongwei Wang ◽  
...  

The phase selection of hyper-peritectic Al-47wt.%Ni alloy solidified under different pressures was investigated. The results show that Al3Ni2 and Al3Ni phases coexist at ambient pressure, while another new phase α-Al exists simultaneously when solidified at high pressure. Based on the competitive growth theory of dendrite, a kinetic stabilization of metastable peritectic phases with respect to stable ones is predicted for different solidification pressures. It demonstrates that Al3Ni2 phase nucleates and grows directly from the undercooled liquid. Meanwhile, the Debye temperatures of Al-47wt.%Ni alloy that fabricated at different pressures were also calculated using the low temperature heat capacity curve.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Aurélien Weiss ◽  
Valérian Chambon ◽  
Junseok K. Lee ◽  
Jan Drugowitsch ◽  
Valentin Wyart

AbstractMaking accurate decisions in uncertain environments requires identifying the generative cause of sensory cues, but also the expected outcomes of possible actions. Although both cognitive processes can be formalized as Bayesian inference, they are commonly studied using different experimental frameworks, making their formal comparison difficult. Here, by framing a reversal learning task either as cue-based or outcome-based inference, we found that humans perceive the same volatile environment as more stable when inferring its hidden state by interaction with uncertain outcomes than by observation of equally uncertain cues. Multivariate patterns of magnetoencephalographic (MEG) activity reflected this behavioral difference in the neural interaction between inferred beliefs and incoming evidence, an effect originating from associative regions in the temporal lobe. Together, these findings indicate that the degree of control over the sampling of volatile environments shapes human learning and decision-making under uncertainty.


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