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Biology subjects

Sentis, A.

Publications and source records attributed to Sentis, A..

8 recordsLinked to original sources

Ecological and evolutionary drivers of thermal performance curves across the tree of life

Biological rates typically follow a unimodal thermal performance curve (TPC), yet the ecological and evolutionary drivers shaping TPC variation remain poorly understood. We compiled an extensive thermal response database covering 896 TPCs for 416 species and 60 traits, spanning microbes to multicellular organisms. Our analyses reveal three key insights. First, environmental seasonality strongly structures TPCs: species in stable environments exhibit narrower thermal ranges and greater asymmetry, with environmental temperature outperforming latitude as a predictor. Second, trait type and organismal complexity modulate thermal sensitivity: emergent traits have narrower ranges than physiological traits, and complex organisms display reduced heat tolerance. Third, prokaryotes and eukaryotes differ fundamentally: while prokaryotes shift thermal limits symmetrically, eukaryotes show constrained upper limits relative to cold tolerance. These findings highlight how environmental stability, trait organization, and evolutionary history shape species thermal niches, providing crucial insights into vulnerability and adaptation under climate change.

ecology↗

Multigenerational effects of temperature exposure on upper thermal limit and mitochondrial functioning in Medaka (Oryzias Latipes) brain

Determining the mechanisms underpinning the thermal limits of organisms is essential to anticipate the impact of climate change on their survival. As mitochondrial activity is key for cellular ATP production, we aimed at investigating the link between mitochondrial dysfunction and the upper thermal limit (CTmax) at which neuromuscular functions are lost. We reared medaka fish (Oryzias latipes) over generations at 20{degrees}C (COLD) and 30{degrees}C (WARM) during five years and measured their CTmax and their mitochondrial oxygen consumption rates (OCRs) at 25{degrees}C and at their CTmax. We found that multigenerational exposure at elevated temperature increases the CTmax by 13%. We observed for all fish a general decrease in the OCRs and for the RCR of complex-I between 25{degrees}C and their CTmax suggesting a link between CTmax and cerebral mitochondrial performance. Finally, we found an increase in the contribution of the mitochondria complex II to OCRs at elevated temperature suggesting that this complex underlie the plasticity in mitochondrial functioning at high temperature. Our study highlights the link between whole organism thermal tolerance and mitochondrial dysfunction and that multigenerational exposure can modify mitochondrial and thermal performance.

ecology↗

The effects of warming on the stability of consumer-resource interactions

Temperature regulates the physiology and behaviour of organisms. Thus, changing temperatures induce dynamics in species interactions. Considering that consumer-resource interactions underpin ecological communities, the impacts of warming on the stability of consumer-resource interactions have been extensively studied. However, a consensus among empirically determined warming-stability relationships and a clear understanding thereof is lacking. To investigate these systematically, we propose a simplified theoretical framework that can incorporate empirical data in three steps. First, we constrain stability to intrinsic oscillations to avoid comparing disparate stability notions. Second, we reduce complexity by utilising a one-dimensional stability metric. Third, we enable the direct comparison of all data by converting all thermal dependence parameterisations into a single function, with two parameters in the exponent determining its shape. The empirical data generate four different warming-stability relationships: stability increases, decreases, is hump-shaped or U-shaped with temperature. The diversity of warming-stability relationships, though partly attributable to context-dependence, is fundamentally caused by sensitivity to two factors: how the processes within the functional response are defined and the thermal dependence of carrying capacity. Consistency across studies regarding the former and acquiring more data on the latter should help uncover systematic patterns in the thermal dependence of stability in consumer-resource interactions.

ecology↗

No model to rule them all: a systematic comparison of 83 thermal performance curve models across traits and taxonomic groups

In ectotherms, the performance of physiological, ecological and life-history traits universally increases with temperature to a maximum before decreasing again. Identifying the most appropriate thermal performance model for a specific trait type has broad applications, from metabolic modelling at the cellular level to forecasting the effects of climate change on population, ecosystem and disease transmission dynamics. To date, numerous mathematical models have been designed, but a thorough comparison among them is lacking. In particular, we do not know if certain models consistently outperform others and how factors such as sampling resolution and trait or organismal identity influence model performance. To fill this knowledge gap, we compile 2,739 thermal performance datasets from diverse traits and taxa, to which we fit a comprehensive set of 83 existing mathematical models. We detect remarkable variation in model performance that is not primarily driven by sampling resolution, trait type, or taxonomic information. Our results reveal a surprising lack of well-defined scenarios in which certain models are more appropriate than others. To aid researchers in selecting the appropriate set of models for any given dataset or research objective, we derive a classification of the 83 models based on the average similarity of their fits.

ecology↗

A framework to improve predictions of warming effects on consumer-resource interactions

Changes in temperature affect consumer-resource interactions, which underpin the functioning of ecosystems. However, existing studies report contrasting predictions regarding the impacts of warming on biological rates and community dynamics. To improve prediction accuracy and comparability, we develop an approach that combines sensitivity analysis and aggregate parameters. The former determines which biological parameters impact the community most strongly. The use of aggregate parameters (i.e., maximal energetic efficiency,{rho} , and interaction strength,{kappa} ), that combine multiple biological parameters, increases explanatory power and reduces the complexity of theoretical analyses. We illustrate the approach using empirically-derived thermal dependence curves of biological rates and applying it to consumer-resource biomass ratio and community stability. Based on our analyses, we generate four predictions: 1) resource growth rate regulates biomass distributions at mild temperatures, 2) interaction strength alone determines the thermal boundaries of the community, 3) warming destabilises dynamics at low and mild temperatures only, 4) interactions strength must decrease faster than maximal energetic efficiency for warming to stabilise dynamics. We argue for the potential benefits of directly working with the aggregate parameters to increase the accuracy of predictions on warming impacts on food webs and promote cross-system comparisons.

ecology↗

Warming indirectly increases invasion success in food webs

Climate warming and biological invasions are key drivers of biodiversity change. Their combined effects on ecological communities remain largely unexplored. We investigated the direct and indirect influences of warming on invasion success, and their synergistic effects on community structure and dynamics. Using size-structured food web models, we found that warming increased invasion success. The direct physiological effects of warming on invasions were minimal in comparison to indirect effects mediated by changes on food web structure and stability. Warmed communities with less connectivity, shortened food chains and reduced temporal variability were more susceptible to invasions. The directionality and magnitude of invasions effects on food webs varied across warming regimes. Warmer communities became smaller, more connected, and with more predator species when invaded than their colder counterparts. They were also less stable and their species more abundant. Considering food web structure is crucial to predict invasion success and its impacts under warming.

ecology↗

Herbivore intraspecific variation and evolutionary divergence drive trophic cascade strength

AO_SCPLOWBSTRACTC_SCPLOWTrophic cascades--the indirect effect of predators on non-adjacent lower trophic levels--are important drivers of the structure and dynamics of ecological communities. However, the influence of intraspecific trait variation on the strength of trophic cascade remains largely unexplored, which limits our understanding of the mechanisms underlying ecological networks. Here we experimentally investigated how intraspecific difference among herbivore lineages specialized on different host plants influences the strength of trophic cascade in a terrestrial tritrophic system. We found that the occurrence and strength of the trophic cascade are strongly influenced by herbivores lineage and host-plant specialization but are not associated with density-dependent effects mediated by the growth rate of herbivore populations. Our findings stress the importance of intraspecific heterogeneities and evolutionary specialization as drivers of the strength of trophic cascades and underline that intraspecific variation should not be overlooked to decipher the joint influence of evolutionary and ecological factors on the functioning of multi-trophic interactions.

ecology↗

Stoichiometric constraints modulate the effects of temperature and nutrients on biomass distribution and community stability

AO_SCPLOWBSTRACTC_SCPLOWTemperature and nutrients are two of the most important drivers of global change. Both can modify the elemental composition (i.e. stoichiometry) of primary producers and consumers. Yet their combined effect on the stoichiometry, dynamics, and stability of ecological communities remains largely unexplored. To fill this gap, we extended the Rosenzweig-MacArthur consumer-resource model by including thermal dependencies, nutrient dynamics, and stoichiometric constraints on both the primary producer and the consumer. We found that stoichiometric constraints dampen the paradox of enrichment and increased persistence at high nutrient levels. Nevertheless, they also reduced consumer persistence at extreme temperatures. Finally, we also found that stoichiometric constraints can strongly influence biomass distribution across trophic levels by modulating consumer assimilation efficiency and resource growth rates along the environmental gradients. In the Rosenzweig-MacArthur model, consumer biomass exceeded resource biomass for most parameter values whereas, in the stoichiometric model, consumer biomass was strongly reduced and sometimes lower than resource biomass. Our findings highlight the importance of accounting for stoichiometric constraints as they can mediate the temperature and nutrient impact on the dynamics and functioning of ecological communities.

ecology↗