Context‐dependent variability in the population prevalence and individual fitness effects of plant–fungal symbiosis

For birds, unpredictable environments during the energetically stressful times of moulting and breeding are expected to have negative fitness effects. Detecting those effects however, might be difficult if individuals modulate their physiology and/or behaviours in ways to minimize short-term fitness costs. Corticosterone in feathers (CORTf) is thought to provide information on total baseline and stress-induced CORT levels at moulting and is an integrated measure of hypothalamic–pituitary–adrenal activity during the time feathers are grown. We predicted that CORTf levels in northern common eider females would relate to subsequent body condition, reproductive success and survival, in a population of eiders nesting in the eastern Canadian Arctic during a capricious period marked by annual avian cholera outbreaks. We collected CORTf data from feathers grown during previous moult in autumn and data on phenology of subsequent reproduction and survival for 242 eider females over 5 years. Using path analyses, we detected a direct relationship between CORTf and arrival date and body condition the following year. CORTf also had negative indirect relationships with both eider reproductive success and survival of eiders during an avian cholera outbreak. This indirect effect was dramatic with a reduction of approximately 30% in subsequent survival of eiders during an avian cholera outbreak when mean CORTf increased by 1 standard deviation. This study highlights the importance of events or processes occurring during moult on subsequent expression of life-history traits and relation to individual fitness, and shows that information from non-destructive sampling of individuals can track carry-over effects across seasons.

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The conflict within: origin, proliferation and persistence of a spontaneously arising selfish mitochondrial genome

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2019.0174 ◽

2019 ◽

Vol 375 (1790) ◽

pp. 20190174 ◽

Cited By ~ 6

Author(s):

Joseph James Dubie ◽

Avery Robert Caraway ◽

McKenna Margaret Stout ◽

Vaishali Katju ◽

Ulfar Bergthorsson

Keyword(s):

Population Dynamics ◽

Mitochondrial Genome ◽

Complex Iii ◽

Population Bottlenecks ◽

Mtdna Copy Number ◽

Fitness Effects ◽

Individual Fitness ◽

Slow Decline ◽

Large Populations ◽

Mitochondrial Genotype

Mitochondrial genomes can sustain mutations that are simultaneously detrimental to individual fitness and yet, can proliferate within individuals owing to a replicative advantage. We analysed the fitness effects and population dynamics of a mitochondrial genome containing a novel 499 bp deletion in the cytochrome b(1) ( ctb-1 ) gene (Δ ctb-1 ) encoding the cytochrome b of complex III in Caenorhabditis elegans. Δ ctb-1 reached a high heteroplasmic frequency of 96% in one experimental line during a mutation accumulation experiment and was linked to additional spontaneous mutations in nd5 and tRNA-Asn . The Δ ctb-1 mutant mitotype imposed a significant fitness cost including a 65% and 52% reduction in productivity and competitive fitness, respectively, relative to individuals bearing wild-type (WT) mitochondria. Deletion-bearing worms were rapidly purged within a few generations when competed against WT mitochondrial DNA (mtDNA) bearing worms in experimental populations. By contrast, the Δ ctb-1 mitotype was able to persist in large populations comprising heteroplasmic individuals only, although the average intracellular frequency of Δ ctb-1 exhibited a slow decline owing to competition among individuals bearing different frequencies of the heteroplasmy. Within experimental lines subjected to severe population bottlenecks ( n = 1), the relative intracellular frequency of Δ ctb-1 increased, which is a hallmark of selfish drive. A positive correlation between Δ ctb-1 and WT mtDNA copy-number suggests a mechanism that increases total mtDNA per se , and does not discern the Δ ctb-1 mitotype from the WT mtDNA. This study demonstrates the selfish nature of the Δ ctb-1 mitotype, given its transmission advantage and substantial fitness load for the host, and highlights the importance of population size for the population dynamics of selfish mtDNA. This article is part of the theme issue ‘Linking the mitochondrial genotype to phenotype: a complex endeavour’.

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Context-dependent fitness effects of behavioral manipulation by a parasitoid

Behavioral Ecology ◽

10.1093/beheco/arp153 ◽

2009 ◽

Vol 21 (1) ◽

pp. 33-36 ◽

Cited By ~ 6

Author(s):

Arne Janssen ◽

Amir H. Grosman ◽

Eduardo G. Cordeiro ◽

Elaine F. de Brito ◽

Juliana Oliveira Fonseca ◽

...

Keyword(s):

Behavioral Manipulation ◽

Fitness Effects ◽

Context Dependent

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Environmentally co-occurring mercury resistance plasmids are genetically and phenotypically diverse and confer variable context-dependent fitness effects

Environmental Microbiology ◽

10.1111/1462-2920.12901 ◽

2015 ◽

Vol 17 (12) ◽

pp. 5008-5022 ◽

Cited By ~ 27

Author(s):

James P.J. Hall ◽

Ellie Harrison ◽

Andrew K. Lilley ◽

Steve Paterson ◽

Andrew J. Spiers ◽

...

Keyword(s):

Mercury Resistance ◽

Fitness Effects ◽

Resistance Plasmids ◽

Context Dependent

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Individual and collective encoding of risk in animal groups

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1905585116 ◽

2019 ◽

Vol 116 (41) ◽

pp. 20556-20561 ◽

Cited By ~ 10

Author(s):

Matthew M. G. Sosna ◽

Colin R. Twomey ◽

Joseph Bak-Coleman ◽

Winnie Poel ◽

Bryan C. Daniels ◽

...

Keyword(s):

Perceived Risk ◽

Structural Connectivity ◽

Group Living ◽

Natural World ◽

Social Cues ◽

Animal Groups ◽

Fish Schools ◽

Individual Fitness ◽

Increased Sensitivity ◽

Context Dependent

The need to make fast decisions under risky and uncertain conditions is a widespread problem in the natural world. While there has been extensive work on how individual organisms dynamically modify their behavior to respond appropriately to changing environmental conditions (and how this is encoded in the brain), we know remarkably little about the corresponding aspects of collective information processing in animal groups. For example, many groups appear to show increased “sensitivity” in the presence of perceived threat, as evidenced by the increased frequency and magnitude of repeated cascading waves of behavioral change often observed in fish schools and bird flocks under such circumstances. How such context-dependent changes in collective sensitivity are mediated, however, is unknown. Here we address this question using schooling fish as a model system, focusing on 2 nonexclusive hypotheses: 1) that changes in collective responsiveness result from changes in how individuals respond to social cues (i.e., changes to the properties of the “nodes” in the social network), and 2) that they result from changes made to the structural connectivity of the network itself (i.e., the computation is encoded in the “edges” of the network). We find that despite the fact that perceived risk increases the probability for individuals to initiate an alarm, the context-dependent change in collective sensitivity predominantly results not from changes in how individuals respond to social cues, but instead from how individuals modify the spatial structure, and correspondingly the topology of the network of interactions, within the group. Risk is thus encoded as a collective property, emphasizing that in group-living species individual fitness can depend strongly on coupling between scales of behavioral organization.

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Energy demand and the context-dependent effects of genetic interactions

10.1101/209510 ◽

2017 ◽

Author(s):

Luke A. Hoekstra ◽

Cole R. Julick ◽

Katelyn M. Mika ◽

Kristi L. Montooth

Keyword(s):

Energy Demand ◽

Developmental Stages ◽

Genetic Interaction ◽

Life Stage ◽

Phenotypic Expression ◽

Fruit Fly ◽

Genetic Effects ◽

Life Stages ◽

Fitness Effects ◽

Context Dependent

ABSTRACTGenetic effects are often context dependent, with the same genotype differentially affecting phenotypes across environments, life stages, and sexes. We used an environmental manipulation designed to increase energy demand during development to investigate energy demand as a general physiological explanation for context-dependent effects of mutations, particularly for those mutations that affect metabolism. We found that increasing the photoperiod during which Drosophila larvae are active during development phenocopies a temperature-dependent developmental delay in a mitochondrial-nuclear genotype with disrupted metabolism. This result indicates that the context-dependent fitness effects of this genotype are not specific to the effects of temperature and may generally result from variation in energy demand. The effects of this genotype also differ across life stages and between the sexes. The mitochondrial-nuclear genetic interaction disrupts metabolic rate in growing larvae, but not in adults, and compromises female, but not male, reproductive fitness. These patterns are consistent with a model where context-dependent genotype-phenotype relationships may generally arise from differences in energy demand experienced by individuals across environments, life stages, and sexes.IMPACT SUMMARYGenetic effects on traits are often context dependent, such that a genotype that improves fitness under one context may have no effect or even a deleterious effect in another context. The external environment is a common context that affects the degree to which a genotype determines a phenotype, but the internal environment of an organism (e.g., its genetic background, sex or life stage) also provides an important context that may modify the phenotypic expression of a genotype. Here we combine new data on the phenotypic effects of a well-characterized genetic interaction between the mitochondrial and nuclear genomes of the fruit fly Drosophila with prior observations to support a model of energy demand as a general explanation for context-dependent genetic effects, particularly for mutations that affect metabolism. We show that the magnitude of fitness effects of this genetic interaction correlates positively with the degree of energy demand among developmental treatments that accelerate growth rate, across developmental stages that differ in the cost of growth, and between sexes with potentially different costs of reproduction. These internal and external contexts create variable demands on energy metabolism that will impact the efficacy of natural selection acting on metabolic mutations in populations.

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Forming Impressions of Personality

Social Psychology ◽

10.1027/1864-9335/a000179 ◽

2014 ◽

Vol 45 (3) ◽

pp. 153-163 ◽

Cited By ~ 13

Author(s):

Sanne Nauts ◽

Oliver Langner ◽

Inge Huijsmans ◽

Roos Vonk ◽

Daniël H. J. Wigboldus

Keyword(s):

Impression Formation ◽

Context Dependent

Asch’s seminal research on “Forming Impressions of Personality” (1946) has widely been cited as providing evidence for a primacy-of-warmth effect, suggesting that warmth-related judgments have a stronger influence on impressions of personality than competence-related judgments (e.g., Fiske, Cuddy, & Glick, 2007 ; Wojciszke, 2005 ). Because this effect does not fit with Asch’s Gestalt-view on impression formation and does not readily follow from the data presented in his original paper, the goal of the present study was to critically examine and replicate the studies of Asch’s paper that are most relevant to the primacy-of-warmth effect. We found no evidence for a primacy-of-warmth effect. Instead, the role of warmth was highly context-dependent, and competence was at least as important in shaping impressions as warmth.

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Memorial Consequences of Environmental Context Change in Children and Adults

Experimental Psychology (formerly Zeitschrift für Experimentelle Psychologie) ◽

10.1027/1618-3169/a000056 ◽

2010 ◽

Vol 57 (6) ◽

pp. 455-461 ◽

Cited By ~ 5

Author(s):

Alp Aslan ◽

Anuscheh Samenieh ◽

Tobias Staudigl ◽

Karl-Heinz T. Bäuml

Keyword(s):

Elementary School ◽

Young Adults ◽

Episodic Memory ◽

Middle Childhood ◽

First Graders ◽

Fourth Graders ◽

Environmental Context ◽

Context Change ◽

Context Dependent

Changing environmental context during encoding can influence episodic memory. This study examined the memorial consequences of environmental context change in children. Kindergartners, first and fourth graders, and young adults studied two lists of items, either in the same room (no context change) or in two different rooms (context change), and subsequently were tested on the two lists in the room in which the second list was encoded. As expected, in adults, the context change impaired recall of the first list and improved recall of the second. Whereas fourth graders showed the same pattern of results as adults, in both kindergartners and first graders no memorial effects of the context change arose. The results indicate that the two effects of environmental context change develop contemporaneously over middle childhood and reach maturity at the end of the elementary school days. The findings are discussed in light of both retrieval-based and encoding-based accounts of context-dependent memory.

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