scholarly journals Size and contrast increase the divertive effect of eyespots

2018 ◽  
Vol 30 (1) ◽  
pp. 159-165 ◽  
Author(s):  
Karin Kjernsmo ◽  
Miranda Grönholm ◽  
Sami Merilaita

Abstract Recent studies have shown that some eyespots of prey divert the strikes of predators, increasing the likelihood of prey escape. However, little is known about what makes eyespots effective divertive (deflective) prey marks. The size of eyespots varies much both between and even within taxa. Yet, whether size is important for the divertive function of eyespots is unknown. Furthermore, eyespots have often been described as highly contrasting, but the effects of contrast on the divertive function of eyespots has never been tested experimentally. Using artificial prey and the three-spined stickleback (Gasterosteus aculeatus) as a model for predator cognition and behavior, we tested the importance of size as well as internal contrast for the divertive effect of eyespots. We independently increased the internal contrast and size of eyespots and found that both increased the divertive effect. The effect of size was significant over all 4 subsequent prey presentations, whereas the effect of contrast decreased after the initial presentations. These results suggest that the size and contrast of divertive marks are probably shaped by selection imposed by predation. We also discuss the involvement of predation in the seasonal and ontogenic plasticity of eyespots found in some taxa.

2002 ◽  
Vol 42 (3) ◽  
pp. 337-344 ◽  
Author(s):  
Miklós K. Páll ◽  
Ian Mayer ◽  
Bertil Borg

2020 ◽  
Author(s):  
Hannah E. A. MacGregor ◽  
Aislinn Cottage ◽  
Christos C. Ioannou

AbstractConsistent inter-individual variation within a population, widely referred to as personality variation, can be affected by environmental context. Feedbacks between an individual’s personality and state can strengthen (positive feedback) or weaken (negative feedback) individual differences when experiences such as predator encounters or winning contests are dependent on personality type. We examined the influence of foraging on individual-level consistency in refuge use (a measure of risk-taking, i.e. boldness) in three-spined sticklebacks, Gasterosteus aculeatus, and particularly whether changes in refuge use depended on boldness measured under control conditions. In the control treatment trials with no food, individuals were repeatable in refuge use across repeated trials, and this behavioral consistency did not differ between the start and end of these trials. In contrast, when food was available, individuals showed a higher degree of consistency in refuge use at the start of the trials versus controls but this consistency significantly reduced by the end of the trials. The effect of the opportunity to forage was dependent on personality, with bolder fish varying more in their refuge use between the start and the end of the feeding trials than shyer fish. This suggests a state-behavior feedback, but there was no overall trend in how individuals changed their behavior, with some individuals spending more, and others less, time in the refuge area at the end than at the start of the trials. Our study shows that personality variation can be suppressed in foraging contexts and a potential but unpredictable role of feedbacks between state and behavior.


2018 ◽  
Vol 41 ◽  
Author(s):  
Peter DeScioli

AbstractThe target article by Boyer & Petersen (B&P) contributes a vital message: that people have folk economic theories that shape their thoughts and behavior in the marketplace. This message is all the more important because, in the history of economic thought, Homo economicus was increasingly stripped of mental capacities. Intuitive theories can help restore the mind of Homo economicus.


2019 ◽  
Vol 42 ◽  
Author(s):  
Jeffrey R. Alberts ◽  
Christopher Harshaw ◽  
Gregory E. Demas ◽  
Cara L. Wellman ◽  
Ardythe L. Morrow

Abstract We identify the significance and typical requirements of developmental analyses of the microbiome-gut-brain (MGB) in parents, offspring, and parent-offspring relations, which have particular importance for neurobehavioral outcomes in mammalian species, including humans. We call for a focus on behavioral measures of social-emotional function. Methodological approaches to interpreting relations between the microbiota and behavior are discussed.


Author(s):  
N. David Theodore ◽  
Mamoru Tomozane ◽  
Ming Liaw

There is extensive interest in SiGe for use in heterojunction bipolar transistors. SiGe/Si superlattices are also of interest because of their potential for use in infrared detectors and field-effect transistors. The processing required for these materials is quite compatible with existing silicon technology. However, before SiGe can be used extensively for devices, there is a need to understand and then control the origin and behavior of defects in the materials. The present study was aimed at investigating the structural quality of, and the behavior of defects in, graded SiGe layers grown by chemical vapor deposition (CVD).The structures investigated in this study consisted of Si1-xGex[x=0.16]/Si1-xGex[x= 0.14, 0.13, 0.12, 0.10, 0.09, 0.07, 0.05, 0.04, 0.005, 0]/epi-Si/substrate heterolayers grown by CVD. The Si1-xGex layers were isochronally grown [t = 0.4 minutes per layer], with gas-flow rates being adjusted to control composition. Cross-section TEM specimens were prepared in the 110 geometry. These were then analyzed using two-beam bright-field, dark-field and weak-beam images. A JEOL JEM 200CX transmission electron microscope was used, operating at 200 kV.


Author(s):  
Peter Pegler ◽  
N. David Theodore ◽  
Ming Pan

High-pressure oxidation of silicon (HIPOX) is one of various techniques used for electrical-isolation of semiconductor-devices on silicon substrates. Other techniques have included local-oxidation of silicon (LOCOS), poly-buffered LOCOS, deep-trench isolation and separation of silicon by implanted oxygen (SIMOX). Reliable use of HIPOX for device-isolation requires an understanding of the behavior of the materials and structures being used and their interactions under different processing conditions. The effect of HIPOX-related stresses in the structures is of interest because structuraldefects, if formed, could electrically degrade devices.This investigation was performed to study the origin and behavior of defects in recessed HIPOX (RHIPOX) structures. The structures were exposed to a boron implant. Samples consisted of (i) RHlPOX'ed strip exposed to a boron implant, (ii) recessed strip prior to HIPOX, but exposed to a boron implant, (iii) test-pad prior to HIPOX, (iv) HIPOX'ed region away from R-HIPOX edge. Cross-section TEM specimens were prepared in the <110> substrate-geometry.


2012 ◽  
Vol 13 (4) ◽  
pp. 111-119 ◽  
Author(s):  
Alexandra Hollo

Language development is the foundation for competence in social, emotional, behavioral, and academic performance. Although language impairment (LI) is known to co-occur with behavioral and mental health problems, LI is likely to be overlooked in school-age children with emotional and behavioral disorders (EBD; Hollo, Wehby, & Oliver, in press). Because language deficits may contribute to the problem behavior and poor social development characteristic of children with EBD, the consequences of an undiagnosed language disorder can be devastating. Implications include the need to train school professionals to recognize communication deficits. Further, it is critically important that specialists collaborate to provide linguistic and behavioral support for students with EBD and LI.


1999 ◽  
Vol 4 (6) ◽  
pp. 5-6

Abstract Personality disorders are enduring patterns of inner experience and behavior that deviate markedly from those expected by the individual's culture; these inflexible and pervasive patterns reflect issues with cognition, affectivity, interpersonal functioning and impulse control, and lead to clinically significant distress or impairment in social, occupational, or other important areas of functioning. The AMA Guides to the Evaluation of Permanent Impairment, Fourth Edition, defines two specific personality disorders, in addition to an eleventh condition, Personality Disorder Not Otherwise Specified. Cluster A personality disorders include paranoid, schizoid, and schizotypal personalities; of these, Paranoid Personality Disorder probably is most common in the legal arena. Cluster B personality disorders include antisocial, borderline, histrionic, and narcissistic personality. Such people may suffer from frantic efforts to avoid perceived abandonment, patterns of unstable and intense interpersonal relationships, an identity disturbance, and impulsivity. Legal issues that involve individuals with cluster B personality disorders often involve determination of causation of the person's problems, assessment of claims of harassment, and assessment of the person's fitness for employment. Cluster C personality disorders include avoidant, dependent, and obsessive-compulsive personality. Two case histories illustrate some of the complexities of assessing impairment in workers with personality disorders, including drug abuse, hospitalizations, and inpatient and outpatient psychotherapy.


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