scholarly journals Selective advantage conferred by resemblance of aposematic mimics to venomous model

2017 ◽  
Vol 17 (3) ◽  
Author(s):  
Frederico Gustavo Rodrigues França ◽  
Vívian da Silva Braz ◽  
Alexandre Fernandes Bamberg de Araújo
Keyword(s):  
Selective Advantage ◽  
Coral Snake ◽  
Selective Force ◽  
Exact Test ◽  
Central Brazil ◽  
Body Regions ◽  
Different Color ◽  
And Behavior ◽  
Model Affect ◽  
Predation Rates

Abstract Mimicry is an excellent example of how natural selection can act on color, morphology, and behavior of species. Herein we assess predation rates on coral snake mimics in Central Brazil, a region with many mimics but only a single model, to answer the following questions: (i) Do predators avoid attacking coral snake mimics? (ii) Does the degree to which mimics resemble their venomous model affect the frequency of predator attacks? (iii) Do predators attack different body regions in mimics with different color patterns? Our experiment was conducted in the Chapada dos Veadeiros National Park, in the municipality of Alto Paraíso de Goiás, state of Goiás, Brazil. To evaluate predation rates on the different mimic patterns, we made 2,400 clay snake replicas using pre-colored nontoxic plasticine and distributed them in open savanna landscapes within the park. A total of 164 (6.83%) replicas were attacked by predators of snakes. Among these attacks, 121 were attacks by birds, and 43 were attacks by carnivorous mammals. Logistic regression and Fisher’s exact test indicated that replicas with red, white, and black coloration are less likely to be attacked than were grey replicas, and coral snake replicas were attacked more often at the “head” end. Also, the greater the similarity to the pattern of venomous coral snakes, the rarer the attack on the replica. Our study underscores the strong selective force that protects coral snake mimics from predators. Our findings reinforce resemblance to the model as an extremely effective strategy in a complex natural system with only one model and numerous mimics.

Using Macrotexture Map to Visualize Texture Heterogeneity in Polycrystalline Aggregate

2021 ◽  
pp. 1-18
Author(s):  
Dongsheng Li
Keyword(s):  
Length Scale ◽  
Polycrystalline Aggregate ◽  
Performance Simulation ◽  
Orientation Imaging ◽  
Behavior Simulation ◽  
Starting Point ◽  
Different Color ◽  
Large Length Scale ◽  
And Behavior ◽  
Texture Characterization

Abstract A new tool, macrotexture map, was developed to represent and visualize texture heterogeneity in polycrystalline aggregate. This is a critical tool for microstructure representation, useful in risk analysis, performance simulation, and hotspot identification. In contrast to orientation imaging microscope (OIM) map where each color represents a crystal orientation, each color in this macrotexture map represents a texture. Different color represent different texture and similar texture shall have similar color. Macrotexture map provide a unique function to quantitatively evaluate texture heterogeneity of large components, leading to a first-hand understanding of property heterogeneity and anisotropy. For an experienced user, these maps serve the same purpose in identifying high risk locations in the investigated component as medical imaging maps do for diagnosis purpose. This method will also serve as a starting point in mesoscale simulation with meshing sensitivity based on the texture heterogeneity. It will provide a bridge between texture characterization and behavior simulation of components with texture heterogeneity. Macrotexture map will offer a linkage between crystal plasticity simulation in small length scale and finite element/difference simulation in large length scale.

NF2 and Spinal Tumors

2006 ◽  
Vol 5 (2) ◽  
pp. 179 ◽  
Author(s):  
Dilys M. Parry
Keyword(s):  
Spinal Tumor ◽  
Spinal Tumors ◽  
Fisher Exact Test ◽  
Radiological Progression ◽  
Intramedullary Tumors ◽  
Exact Test ◽  
Extramedullary Tumor ◽  
Clinical Records ◽  
And Behavior

Object The authors conducted a study to examine the incidence, classification, and progression of spinal tumors in patients with neu-rofibromatosis Type 2 (NF2) treated at a single center, and to examine relationships with the known mutational subtypes of NF2. Methods They performed a retrospective review of clinical records, neuroimaging studies, and genetic data obtained in 61 patients with NF2. Forty-one (67%) of 61 patients harbored one or more spinal tumors. Thirty-four patients had undergone serial spinal magnetic resonance imaging during a mean follow-up period of 52 months (range 10–103 months; median 53 months). In 16 patients there were multiple extramedullary tumors smaller than 5 mm, which did not progress. Fourteen patients harbored at least one extramedullary tumor that was greater than 5 mm; of these, radiological progression was demonstrated or spinal tumor excision was performed during the follow-up period in eight cases (57%). Eleven patients harbored intramedullary cord tumors in addition to small and large extramedullary tumors, three (27%) of which exhibited radiological progression. In cases in which genotypes were known, protein-truncating mutations were significantly more likely to be associated with the presence of spinal tumors than in other types (p = 0.03, Fisher exact test). No associations between clinical behavior of spinal tumors and genotype, however, could be demonstrated. Conclusions Spinal tumors in cases involving NF2 are heterogeneous in type, distribution, and behavior but larger-size tumors are more likely to progress significantly. Intramedullary tumors usually accompany multiple extramedullary tumors. In the authors' experience subtyping of the NF2 mutation has not yet influenced management. Protein-truncating mutations are associated with an increased prevalence of spinal tumors.

scholarly journals Edge effect on post-dispersal artificial seed predation in the southeastern Amazonia, Brazil

2015 ◽  
Vol 75 (2) ◽  
pp. 347-351 ◽  
Author(s):  
G. Penido ◽  
V. Ribeiro ◽  
DS. Fortunato
Keyword(s):  
Edge Effect ◽  
Seed Predation ◽  
Linear Models ◽  
Site Effect ◽  
Amazon Forest ◽  
Complete Model ◽  
Central Brazil ◽  
Artificial Seed ◽  
Seed Distribution ◽  
Predation Rates

This paper evaluates the post-dispersal artificial seed predation rates in two areas of the southeastern Amazon forest-savanna boundary, central Brazil. We conducted the survey in a disturbance regime controlled research site to verify if exists an edge effect in these rates and if the disturbance (in this case annual fire and no fire) affects seed predation. We placed 800 peanuts seeds in each area at regular distance intervals from the fragment`s edge. Data were analyzed by a likelihood ratio model selection in generalized linear models (GLM). The complete model (with effects from edge distance and site and its interaction) was significative (F3=4.43; p=0.005). Seeds had a larger predation rates in fragment’s interior in both areas, but in the controlled area (no disturbance) this effect was less linear. This suggests an edge effect for post-dispersal seed predation, and that disturbances might alter these effects. Even if we exclude the site effect (grouping both areas together) there is still a strong edge effect on seed predation rates (F3=32.679; p>0.001). We did not verify predator’s species in this study; however, the presence of several species of ants was extremely common in the seeds. The detection of an edge effect in only a short survey time suggests that there is heterogeneity in predation rates and that this variation might affect plant recruitment in fragmented areas of the Amazon forest. Henceforth, this seed predation should be taken in consideration in reforestation projects, where the main source of plants species is from seed distribution.

Larval Mosquitoes as Vulnerable Prey: Chaoborus Predation

1989 ◽  
Vol 46 (9) ◽  
pp. 1642-1650 ◽  
Author(s):  
J. C. Helgen
Keyword(s):  
Daphnia Pulex ◽  
Choice Experiments ◽  
Distinct Difference ◽  
Prey Choice ◽  
Temporary Wetlands ◽  
Aedes Vexans ◽  
Selective Force ◽  
Chaoborus Americanus ◽  
Predation Rates

The vulnerability of instar I and II larvae of the mosquito Aedes vexans as prey for Chaoborus americanus is much greater than that of the small coexisting prey, Daphnia pulex. Predation on Aedes larvae could reduce Aedes populations in overlapping habitats, and be a selective force in driving Aedes to lay eggs in muds of more temporary wetlands. Predation rates are great (7–25∙d−1) and ingestion times are rapid (0.8–6 s) on Aedes instars I and II. In prey choice experiments, Chaoborus strongly prefers Aedes I over small Daphnia. An Aedes diet promotes growth of Chaoborus at least as well as a Daphnia diet. Larval Aedes behaviors show a distinct difference between the first two and last two instars. Aedes swimming speeds and swimming distances increase with each instar, but when disturbed, the first two instars significantly reduce their swimming distances. Calculated prey vulnerabilities, based on swimming speeds and reciprocal ingestion times, suggest a much greater vulnerability for Aedes I and II than that for small (0.8 mm) Daphnia or for Aedes III and IV (4.6–6.2 mm).

A new species of Bokermannohyla (Anura: Hylidae) from highlands of Central Brazil

Zootaxa ◽  
2012 ◽  
Vol 3527 (1) ◽  
pp. 28 ◽  
Author(s):  
REUBER ALBUQUERQUE BRANDÃO ◽  
RAFAEL FÉLIX DE MAGALHÃES ◽  
ADRIAN ANTONIO GARDA ◽  
LEANDRO ABRóSIO CAMPOS ◽  
ANTONIO SEBBEN ◽  
...  
Keyword(s):  
New Species ◽  
Medium Size ◽  
Spectral Features ◽  
Independent Variables ◽  
Central Brazil ◽  
Iris Color ◽  
Gallery Forests ◽  
Distrito Federal ◽  
And Behavior ◽  
A New Species

We describe a new species of hylid frog, Bokermannohyla sapiranga sp. nov., from Central Brazil (15°55’49” S,47°52’59” W, 1110m asl). The species is characterized by medium size (males snout-vent length 45.6±4.7mm, N=13; fe-males 46.9±6.2, N=4) for the B. pseudopseudis group and by iris color varying from orange to reddish. The advertisementcall is similar in some aspects to calls of B. pseudopseudis, but differs mainly by structure and spectral features, but alsotemporal ones such as call length, note duration, and number of notes per call. The new species uses streams with muddybeds in gallery forests as well as rocky bed streams in the highlands of Goiás State and Distrito Federal. The new speciesis tentatively included in the B. pseudopseudis group based on shared morphological features, ecology, and behavior. Mor-phometric analysis of size-independent variables indicated that B. sapiranga differs from B. pseudopseudis mostly in head length and width, interorbital distance, and diameter of the fourth toe disc.

Contrasting parental color morphs increase regularity of prey deliveries in an African raptor

2020 ◽  
Vol 31 (5) ◽  
pp. 1142-1149
Author(s):  
Carina Nebel ◽  
Petra Sumasgutner ◽  
Shane C McPherson ◽  
Gareth J Tate ◽  
Arjun Amar
Keyword(s):  
Environmental Conditions ◽  
Survival Rates ◽  
Selective Advantage ◽  
Color Polymorphism ◽  
Color Morphs ◽  
Complementarity Hypothesis ◽  
Selection For ◽  
Different Color ◽  
The Stability ◽  
Capture Rates

Abstract Disassortative mating in color-polymorphic raptors is a proposed mechanism for the maintenance of color polymorphism in populations. Selection for such a mating system may occur if there are fitness advantages of mating with a contrasting morph. In the black sparrowhawk (Accipiter melanoleucus), mixed-morph pairs may have a selective advantage because they produce offspring that have higher survival rates. Two hypotheses, which may explain the mechanism, are the “avoidance-image” and “complementarity” hypotheses. The first suggests that, within a predator’s territory, prey develop a search image for the more commonly encountered parental morph, for example, the male morph during incubation and brooding. Females of a contrasting morph to their partner would then have higher capture rates once they commence hunting in the later nestling phase. Thus, the “avoidance-image” hypothesis predicts higher provisioning rates for mixed-morph pairs. Alternatively, the “complementarity” hypothesis posits that different color morphs exploit different environmental conditions, allowing mixed-morph pairs to hunt under a wider range of conditions and predicts that food is delivered more consistently. We test these hypotheses using nest cameras to record prey delivery rates during the late nestling phase when both parents are hunting. We found support for the “complementarity” hypothesis, with mixed-morph pairs delivering food more consistently but not at a higher rate. This higher consistency in prey deliveries may explain the improved survival of the offspring of mixed-morph pairs and could, therefore, play a role in maintaining the stability of color polymorphism in this system.

scholarly journals Faunal composition and behavior of Anopheline mosquitoes in the Xavánte Indian reservation of Pimentel Barbosa, Central Brazil

Parasite ◽  
1998 ◽  
Vol 5 (2) ◽  
pp. 197-202 ◽  
Author(s):  
R.V. Ianelli ◽  
N. A. Honorio ◽  
D.C. Lima ◽  
R. Lourenço-de-Oliveira ◽  
R. V. Santos ◽  
...  
Keyword(s):  
Indian Reservation ◽  
Faunal Composition ◽  
Central Brazil ◽  
And Behavior ◽  
Anopheline Mosquitoes

Counting Ticks (Acari: Ixodida) on Hosts Is Complex: A Review and Comparison of Methods

2019 ◽  
Vol 56 (6) ◽  
pp. 1527-1533 ◽  
Author(s):  
Henry W Lydecker ◽  
Peter B Banks ◽  
Dieter F Hochuli
Keyword(s):  
Fundamental Aspect ◽  
Ecological Research ◽  
Ethical Considerations ◽  
Detection Ability ◽  
Future Studies ◽  
Body Regions ◽  
Tick Distribution ◽  
Practice Variability ◽  
Simple Measurement ◽  
And Behavior

Abstract Locating and counting parasites on a host is a fundamental aspect of ecological research and basic veterinary and clinical practice. Variability in the biology and behavior of both hosts and parasites creates many methodological, logistical, and ethical considerations that must be made to collect this deceptively simple measurement. We identified methods that are used to count ticks (Acari: Ixodida, Leach 1815) on hosts by reviewing the methods sections of relevant published studies. Unfortunately, there is no best method agreed upon by scientists to collect ticks from hosts. In general, we suggest that studies focusing purely on counting ticks on hosts should use more sensitive methods to determine patterns of tick distribution on the surfaces of unconscious or deceased hosts in order to provide host body regions to target in future studies to maximize tick detection ability and limit the costs of research for researchers and the host animals involved. As ticks are counted on hosts for many different reasons, researchers must be goal oriented and chose methods that are appropriate for addressing their specific aims.

scholarly journals Cognitive performance and behavior across idiopathic/genetic epilepsies in children and adolescents

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Frederik Jan Moorhouse ◽  
Sonia Cornell ◽  
Lucia Gerstl ◽  
Moritz Tacke ◽  
Timo Roser ◽  
...  
Keyword(s):  
Cognitive Performance ◽  
Behavioral Problems ◽  
Exact Test ◽  
Behavioral Parameters ◽  
Group 2 ◽  
Mean Differences ◽  
Genetic Epilepsies ◽  
And Behavior ◽  
The University ◽  
Post Hoc

AbstractWe investigated the cognitive and behavioral profile of three distinct groups of epilepsies with a genetic background for intergroup differences: (1) idiopathic/genetic generalized epilepsies (IGE/GGE group); (2) idiopathic focal epilepsies (IFE group); and (3) epilepsies with proven or strongly suggested monogenic or structural/numeric chromosomal etiology (genetic epilepsies, GE group). Cognitive (total IQ and subcategories) and behavioral parameters (CBCL) were assessed at the tertiary epilepsy center of the University of Munich (Germany). We used ANOVA with post-hoc Bonferroni-correction to explore significant mean differences and Fisher’s exact test for significant proportional differences of intelligence impairment and behavioral problems. 126 (56 IGE/GGE, 26 IFE, 44 GE) patients were available. Total IQ was 89.0 ± 15.9 (95% CI 84.5–93.4) for IGE/GGE, 94.8 ± 18.1 (95% CI 87.3–102.3) for IFE and 76.4 ± 22.4 (95% CI 67.6–85.3) for GE (p = 0.001). The same trend was significant for all but one IQ subcategory. The rate of patients with an intelligence impairment (total IQ < 70) was higher for GE (40%) than for IGE/GGE (14%) and for IFE (7%) patients (p = 0.033). There were no significant differences between groups for behavior scores and behavioral problems. This study shows that the current ILAE classification of epilepsies with genetic etiology creates a heterogeneous group of patients with respect to cognitive performance but not behavior. These findings may help in further delineating epilepsies as regards cognitive performance, notwithstanding their closely related etiological classification.

scholarly journals THE EVOLUTION OF SELF-REGULATED TRANSPOSITION OF TRANSPOSABLE ELEMENTS

Genetics ◽  
1986 ◽  
Vol 112 (2) ◽  
pp. 359-383
Author(s):  
B Charlesworth ◽  
C H Langley
Keyword(s):  
Transposable Elements ◽  
High Frequency ◽  
Germ Line ◽  
Genetic Recombination ◽  
Somatic Cells ◽  
Selective Advantage ◽  
Selective Force ◽  
Cis Acting ◽  
Bacterial Plasmids ◽  
Regulatory Effects

ABSTRACT This paper examines the conditions under which self-regulated rates of transposition can evolve in populations of transposable elements infecting sexually reproducing hosts. Models of the evolution of both cis-acting regulation (transposition immunity) and trans-acting regulation (transposition repression) are analyzed. The potential selective advantage to regulation is assumed to be derived from the deleterious effects of mutations associated with the insertion of newly replicated elements. It is shown that both types of regulation can easily evolve in hosts with low rates of genetic recombination per generation, such as bacteria or bacterial plasmids. Conditions are much more restrictive in organisms with relatively free recombination. In haploids, the main selective force promoting regulation is the induction of lethal or sterile mutations by transposition; in diploids, a sufficiently high frequency of dominant lethal or sterile mutations associated with transpositions is required. Data from Drosophila and maize suggest that this requirement can sometimes be met. Coupling of regulatory effects across different families of elements would also aid the evolution of regulation. The selective advantages of restricting transposition to the germ line and of excising elements from somatic cells are discussed.

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