Search results for "trade-off."

Data from: Experimental evolution of an emerging plant virus in host genotypes that differ in their susceptibility to infection

2014

This study evaluates the extent to which genetic differences among host individuals from the same species conditions the evolution of a plant RNA virus. We performed a three-fold replicated evolution experiment in which Tobacco etch potyvirus isolate At17b (TEV-At17b), adapted to Arabidopsis thaliana ecotype Ler-0, was serially passaged in five genetically heterogeneous ecotypes of A. thaliana. After 15 passages we found that evolved viruses improved their fitness, showed higher infectivity and stronger virulence in their local host ecotypes. The genome of evolved lineages was sequenced and putative adaptive mutations identified. Host-driven convergent mutations have been identified. Eviden…

Data from: Inbreeding-related trade-offs in stress-resistance in the ant Formica exsecta

2014

Inbred individuals and populations are predicted to suffer from inbreeding depression, especially in times of stress. Under natural conditions, organisms are exposed to more than one stressor at any one time, highlighting the importance of stress resistance traits. We studied how inbreeding- and immunity-related traits are correlated under different dietary conditions in the ant Formica exsecta. Its natural diet varies in the amount and nature of plant secondary compounds and the level of free radicals, all of which require detoxification to maintain organismal homeostasis. We found that inbreeding decreased general antibacterial activity under dietary stress, suggesting inbreeding-related …

Data from: Multiple aspects of plasticity in clutch size vary among populations of a globally distributed songbird

2014

1. Plasticity in life-history characteristics can influence many ecological and evolutionary phenomena, including how invading organisms cope with novel conditions in new locations or how environmental change affects organisms in native locations. Variation in reaction norm attributes is a critical element to understanding plasticity in life history, yet we know relatively little about the ways in which reaction norms vary within and among populations. 2. We amassed data on clutch size from marked females in eight populations of house sparrows (Passer domesticus) from North America and Europe. We exploited repeated measures of clutch size to assess both the extent of within-individual pheno…

The energetic cost of humoral immunity in the Collared Dove, Streptopelia decaocto : is the magnitude sufficient to force energy-based trade-offs?

2005

International audience; 1. Energy saving is often suggested as the basis of a resource trade-off between immunocompetence and other fitness-relevant traits. This suggests that the energetic cost of an immune response is significant and sufficient to force trade-offs. To date, few studies have investigated the energetic cost of the humoral component of the immune system in birds and furthermore, existing results are contradictory. 2. We addressed this question through two experiments. In experiment 1, the basal metabolic rate (BMR) of Collared Doves, Streptopelia decaocto , challenged with sheep red blood cells (SRBC) was compared with the BMR of control birds. The energetic cost of immunity…

The effect of prey resources on evolutionary and ecological dynamics of prey (Serratia marcescens) and predator (Tetrahymena thermophila)

2006

Data from: The oxidative cost of reproduction depends on early development oxidative stress and sex in a bird species

2016

In the early 2000’s, a new component of the cost of reproduction was proposed: oxidative stress. Since then the oxidative cost of reproduction hypothesis has, however, received mixed support. Different arguments have been provided to explain this. Among them, the lack of a life history perspective on most experimental tests was suggested. We manipulated the levels of a key intracellular antioxidant (glutathione) in captive zebra finches (Taeniopygia guttata) during a short period of early life and subsequently tested the oxidative cost of reproduction. Birds were allowed to mate freely in an outdoor aviary during several months. We repeatedly enlarged or reduced their broods to increase or …

Profit vs morality: how unfair is labor market discrimination? Results from a survey experiment

2019

Using an original survey-experimental protocol, we study the normative acceptability of the trade-off between immoral profit (discrimination) and costly morality (non-discrimination). We test the causal influence of three factors: i) the origin of discrimination, ii) the steepness of the morality/profit trade-off and iii) anti-discriminatory moral injunctions. Contrasting with past experimental and attitudinal studies, we find that a significant minority of respondents believe that labor market discrimination is acceptable when morality results in profit loss. We also find that the three tested factors have significant effects on normative opinions. Respondents are more likely to choose pro…

Optimizing management to enhance multifunctionality in a boreal forest landscape

2017

The boreal biome, representing approximately one-third of remaining global forests, provides a number of crucial ecosystem services. A particular challenge in forest ecosystems is to reconcile demand for an increased timber production with provisioning of other ecosystem services and biodiversity. However, there is still little knowledge about how forest management could help solve this challenge. Hence, studies that investigate how to manage forests to reduce trade-offs between ecosystem services and biodiversity are urgently needed to help forest owners and policy makers take informed decisions. We applied seven alternative forest management regimes using a forest growth simulator in a la…

Ravintoresurssin ajallisen vaihtelun vaikutus saaliin (Serratia marcescens -bakteeri) ja pedon (Tetrahymena thermophila -alkueläin) evolutiiviseen ja…

2010

Resurssit ovat yksi tärkeimmistä eliöiden evoluutioon vaikuttavista ympäristötekijöistä. Esimerkiksi eliöiden kyky kilpailla ja puolustautua voivat kehittyä erilailla ravintoympäristöstä ja sen muutoksista riippuen: hyvä resurssisaatavuus voi mahdollistaa kalliisiin puolustusominaisuuksiin allokoimisen, kun taas resurssien puute voi estää saaliin puolustusominaisuuksien evoluution. Tutkin saalistuksen ja ympäristön vaihtelun vaikutusta faktoriaalisessa mikrokosmos kokeessa, jossa saalisbakteereita (Serratia marcescens) kasvatettiin joko yksin (kontrollit) tai yhdessä alkueläinpedon (Tetrahymena thermophila) kanssa vakaassa tai vaihtelevassa ravintoresurssiympäristössä 8 viikon ajan. Petojen…

The evolution and ecology of multiple antipredator defences

2023

Prey seldom rely on a single type of antipredator defence, often using multiple defences to avoid predation. In many cases, selection in different contexts may favour the evolution of multiple defences in a prey. However, a prey may use multiple defences to protect itself during a single predator encounter. Such “defence portfolios” that defend prey against a single instance of predation are distributed across and within successive stages of the predation sequence (encounter, detection, identification, approach (attack), subjugation and consumption). We contend that at present, our understanding of defence portfolio evolution is incomplete, and seen from the fragmentary perspective of speci…