Search results for "DEP"

Safety in Numbers: How Color Morph Frequency Affects Predation Risk in an Aposematic Moth

2021

Polymorphic warning signals in aposematic systems are enigmatic because predator learning should favor the most common form, creating positive frequency-dependent survival. However, many populations exhibit variation in warning signals. There are various selective mechanisms that can counter positive frequency-dependent selection and lead to temporal or spatial warning signal diversification. Examining these mechanisms and their effects requires first confirming whether the most common morphs are favored at both local and regional scales. Empirical examples of this are uncommon and often include potentially confounding factors, such as a lack of knowledge of predator identity and behavior. …

Heterozygote advantage and pleiotropy contribute to intraspecific color trait variability

2022

The persistence of intrapopulation phenotypic variation typically requires some form of balancing selection because drift and directional selection eventually erode genetic variation. Heterozygote advantage remains a classic explanation for the maintenance of genetic variation in the face of selection. However, examples of heterozygote advantage, other than those associated with disease resistance, are rather uncommon. Across most of its distribution, males of the aposematic moth Arctia plantaginis have two hindwing phenotypes determined by a heritable one locus-two allele polymorphism (genotypes: WW/Wy = white morph, yy = yellow morph). Using genotyped moths, we show that the presence of o…

Weak warning signals can persist in the absence of gene flow

2019

Aposematic organisms couple conspicuous warning signals with a secondary defense to deter predators from attacking. Novel signals of aposematic prey are expected to be selected against due to positive frequency-dependent selection. How, then, can novel phenotypes persist after they arise, and why do so many aposematic species exhibit intrapopulation signal variability? Using a polytypic poison frog (Dendrobates tinctorius), we explored the forces of selection on variable aposematic signals using 2 phenotypically distinct (white, yellow) populations. Contrary to expectations, local phenotype was not always better protected compared to novel phenotypes in either population; in the white popul…

The impact of life stage and pigment source on the evolution of novel warning signal traits

2021

Our understanding of how novel warning color traits evolve in natural populations is largely based on studies of reproductive stages and organisms with endogenously produced pigmentation. In these systems, genetic drift is often required for novel alleles to overcome strong purifying selection stemming from frequency-dependent predation and positive assortative mating. Here, we integrate data from field surveys, predation experiments, population genomics, and phenotypic correlations to explain the origin and maintenance of geographic variation in a diet-based larval pigmentation trait in the redheaded pine sawfly (Neodiprion lecontei), a pine-feeding hymenopteran. Although our experiments c…

Diversity in warning coloration: selective paradox or the norm?

2019

Aposematic theory has historically predicted that predators should select for warning signals to converge on a single form, as a result of frequency-dependent learning. However, widespread variation in warning signals is observed across closely related species, populations and, most problematically for evolutionary biologists, among individuals in the same population. Recent research has yielded an increased awareness of this diversity, challenging the paradigm of signal monomorphy in aposematic animals. Here we provide a comprehensive synthesis of these disparate lines of investigation, identifying within them three broad classes of explanation for variation in aposematic warning signals: …

Pirmsskolas vecuma bērnu vecāku pašefektivitātes, viņu uztvertā sociālā atbalsta un depresija pazīmju saistība ar bērnu audzināšanas pieejām

2020

Šī maģistra darba mērķis ir atbildēt uz jautājumu, kāda saistība pastāv starp vecāku pašefektivitātes izjūtu, vecāk uztverto sociālo atbalstu un izjustajām depresijas pazīmēm ar bērnu audzināšanas pieejām? Pētījumā piedalījās 96 vecāki, no tiem 94 mātes un 2 tēvi, kuriem ir bērni vecumā no 3-7 gadu vecumam, ar noteikumu, ka nav uzsākuši mācības skolā. Aptauja tika izplatīta elektroniski izmantojot “Facebook” lietotni. Šajā pētījumā tika izmantotas “Ģentes audzināšanas pieejas skala”, “Daudzdimensionālā sajustā sociālā atbalsta skala”, kas tika papildināta ar apgalvojumiem saistībā ar sajusto atbalstu no baznīcas (mācītāja, kāda cilvēka, kas ir piederīgs kādai draudzei),“Pašefektivitātes izj…

The impact of summertime food consumption by vendace on the abundance of zooplankton the following spring

2008

Zidane, lógica del honor contra lógica profesional

2006

Olof Schalberg : akateeminen perintö ja teoreettisen filosofian rappiotila

2022

Behavioral Activation through Virtual Reality for Depression: A Single Case Experimental Design with Multiple Baselines

2022

Behavioral activation (BA) is a structured psychotherapeutic approach for the treatment of major depressive disorder (MDD), which aims at increasing the engagement in activities that might bring enjoyment and meaning to patients’ lives. Although a growing body of evidence supports the effectiveness of BA, enhancing the motivation and activity level of depressed patients is often challenging. In the present study, we explored the effectiveness of a brief BA treatment supported by virtual reality (VR) to facilitate the visualization and anticipation of four pleasurable activities that we tried to re-introduce in the patients’ daily routine. To do so, we conducted a single-case experimental de…