122 research outputs found
Data from Sentis et al. (2015) for main publication
No full textFunctional response data provided by Arnaud Sentis and colleagues (https://doi.org/10.1111/gcb.12931).
“Daphnia_density” is the initial prey number; “Daphnia_eaten” is the number of eaten prey individuals after the experiment. Please see the original publication by Sentis et al. (2015, https://doi.org/10.1111/gcb.12931) for details and also cite their paper if using these data! These data appear only in the main publication (D1) published in MEE
Data for Sentis et al. Short-term thermal acclimation modulates predator functional response
No full textData from the study Short-term thermal acclimation modulates predator functional response by Arnaud Sentis, Lukas Veselý, Marek Let, Martin Musil, Viktoriia Malinovska and Antonín Kouba.
The data represent the number of prey eaten for different initial prey densities, temperatures and acclimation times.
The first column "temperature" represents the experimental temperature.
The second column "acl.time" represents the duration of acclimation at each of the experimental temperature before the predation trials
The third column "PreyDensity" represents the initial prey density at the begining of the predation trial
The column "alive indiv." represents the number of prey alive at the end of the predation trial
The column "dead indiv." represents the number of prey dead but not eaten at the end of the predation trial
The column "indiv. into pieces" represents the number of dead prey with visible attack marks at the end of the predation trial
The column "PreyEaten" represents the number of prey eaten at the end of the predation trial
The column "PreyEatenNCM" represents the number of prey eaten and killed but not eaten at the end of the predation trial
Each row represents a single observation (i.e. predation trial).
Predators and prey were used only once
R code for Sentis et al. Intraspecific difference among herbivore lineages and their host-plant specialization drive the strength of trophic cascades
No full textR codes for Sentis et al. (2020) Intraspecific difference among herbivore lineages and their host-plant specialization drive the strength of trophic cascades
Data from: Stoichiometric constraints modulate the effects of temperature and nutrients on biomass distribution and community stability
No full textTemperature 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.Directions for running code in R
1. Place all R codes in your working directory
2. run the R code "generate starting values" to produce the starting values for the simulations
3. run the R code "Models" for the simulations with the RM and SRM models
4. Plot the results using the R code "Models".
For more information see Sentis, A., B. Haegeman and J. M. Montoya. "Stoichiometric constraints modulate the effects of temperature and nutrients on biomass distribution and community stability." on Biorxiv
Thermal stress effects on herbivores and their predators: Implications for biological control
No full textEffet de la température sur les interactions trophiques et intraguildes au sein d’un système plante-herbivore-ennemis naturels : modélisation et approches expérimentales
No full textDoctorat réalisé en cotutelle entre l'Université de Montréal et l'Université Paul Sabatier-Toulouse IIIIl est maintenant reconnu que les changements climatiques ont des impacts importants sur l’ensemble des organismes vivants. Parmi les facteurs de ces changements, la température occupe une place prépondérante pour les organismes ectothermes car elle régule leur métabolisme. Toutefois, bien que les effets de la température sur les individus d’une espèce soient largement connus, les connaissances demeurent limitées quant aux conséquences sur les interactions trophiques. Dans ce contexte, notre étude s’intéresse aux effets de la température sur un système biologique composé d’une plante, le poivron Capsicum annuum L., d’un herbivore, le puceron Myzus persicae Sulzer (proie extraguilde), ainsi que de deux de ses ennemis naturels : la coccinelle maculée Coleomegilla maculata lengi Timberlake (prédateur intraguilde) et la cécidomyie prédatrice Aphidoletes aphidimyza Rondani (proie intraguilde). Dans ce but, nous avons opté pour une approche multiple comprenant : (1) la modélisation des interactions prédateur-proie et intraguilde (prédation entre deux compétiteurs d’espèces différentes qui exploitent une même ressource), (2) la réalisation d’expériences empiriques en laboratoire permettant de tester les prédictions des modèles et de caractériser l’effet de la température et de ses variations sur les composantes du système biologique étudié. Conformément aux prédictions d’un premier modèle, nous mettons en évidence que, lorsque la température augmente, C. maculata est plus efficace pour trouver et manipuler ses proies, ce qui augmente le taux de prédation. En revanche, à haute température son efficacité de recherche décroît, ce qui entraîne une diminution du taux de prédation. L’activité de prédation se limite donc à une fenêtre thermique en dehors de laquelle elle est réduite ou nulle. Par la suite, nous comparons un modèle linéaire et un modèle non-linéaire (saturant à haute densité de proies) afin de déterminer lequel de ces deux modèles décrit le mieux la réponse fonctionnelle d’un prédateur intraguilde, c’est-à-dire la relation entre le nombre de proies consommées et la densité de proies. Nos résultats expérimentaux démontrent que les prédictions du modèle non-linéaire correspondent bien aux observations empiriques, tandis que le modèle linéaire surestime largement le nombre de proies consommées et la fréquence des interactions intraguildes. Par la suite, nous dérivons le modèle non-linéaire afin d’y inclure l’effet de la température. Comme prédit par ce dernier modèle, la prédation intraguilde devient plus fréquente lorsque la température augmente mais diminue lorsqu’il y a davantage de proies extraguildes. Dans une dernière étude, nous soumettons le système biologique à des pics de température. Nos résultats démontrent que ces pics diminuent la fécondité des pucerons, l’accroissement de leurs populations, le poids des larves de coccinelles et le contrôle des pucerons par les coccinelles mais n’ont pas d’effets sur la plante et les relations plante-insecte. Le système biologique s’avère également plus résistant aux pics de température en présence de coccinelles qu’en leur absence. En conclusion, notre étude souligne l’importance de considérer la température dans les interactions trophiques puisqu’elle influence le comportement des organismes et la fréquence de leur interaction, ce qui se répercute au niveau des populations et des communautés.There are several pieces of evidence that climate change significantly impact plants, herbivores, and predators. For ectotherms, temperature is the most important factor associated with these changes as it regulates their metabolism. Although the effects of temperature on individual organisms or populations have been well documented, our understanding about their consequences on trophic and guild interactions remains limited. In this context, we investigated the effects of temperature on complex interactions between a plant, the pepper Capsicum annuum L.; an herbivore, the aphid Myzus persicae Sulzer (extraguild prey); and two of its natural enemies, the ladybeetle Coleomegilla maculata lengi Timberlake (intraguild predator) and the predatory midge Aphidoletes aphidimyza Rondani (intraguild prey). We combined two approaches: (1) modeling predator–prey and intraguild (predation between two species that compete for the same resource) interactions, and (2) testing model predictions and characterizing the effects of temperature on components of our biological system through laboratory experiments. As predicted by the first model, we found that when temperature rises, C. maculata is more efficient at finding and handling prey, which increases predation rate. However, search rate decreases at high temperatures, leading to a reduction in predation. The predatory activity is therefore limited to a temperature window outside of which predation is reduced or absent. The next objective was to compare two models, one linear and one nonlinear, to determine which one best describes the functional response (the relationship between the number of prey consumed and prey density) of an intraguild predator. Results indicated that predictions of the nonlinear model (i.e., saturating at high prey densities) fit empirical observations well while the linear model greatly overestimates the number of prey consumed and the incidence of intraguild predation. Subsequently, we derived the nonlinear model to include the effect of temperature. As predicted by this model, we found that the incidence of intraguild predation increases with temperature but decreases when extraguild prey are more abundant. In a last experiment, we investigated the effects of temperature peaks on each component of our biological system. Results showed that temperature peaks reduce aphid fecundity and thereby population growth, decrease the weight of ladybeetle larvae, and decrease aphid control by ladybeetles, but have no effect on plants or plant–insect relationships. We also observed that the food chain is more resistant to temperature peaks when ladybeetles are included in the system than when they are absent. This suggests that ecosystems with predators exerting strong biotic control on prey population should be more resistant to climate change than ecosystem lacking them. In conclusion, our study highlights the importance of considering temperature in trophic and guild interactions since it influences the behavior of organisms as well as the frequency of interactions that affect population and community dynamics
Virus mediated trophic interactions between aphids and their natural enemies
No full textMicrobial endosymbionts alter the phenotype of their host which may have cascading effects at both population and community levels. However, we currently lack information on whether the effects of viruses on both host phenotypic traits and host population demography can modify interactions with upper trophic levels. To fill this gap, we investigated whether a prevalent densovirus infecting the aphid Myzus persicae (i.e., MpDNV) can modify trophic interactions between host aphids and their natural enemies (i.e., predators and parasitoids) by influencing aphid phenotypic traits (i.e., body mass and defensive behaviours), population demography (i.e. density and age-structure) and susceptibility towards both predation and parasitism. We found that the virus decreased aphid body mass but did not influence their behavioural defences. At the population level, the virus had a minor effect on aphid adult mortality whereas it strongly reduced the density of nymphs and influenced the stage structure of aphid populations. In addition, the virus enhanced the susceptibility of aphids to parasitism regardless of the parasitoid species. Predation rate on adult aphids was not influenced by the virus but ladybeetle predators strongly decreased the number of aphid nymphs, especially for uninfected ones compared to infected ones. As a result, the virus decreased predator effects on aphid populations. By reducing both aphid quality and availability, increasing their susceptibility to parasitism, and modulating predator effect on aphid populations, we highlighted that viral endosymbionts can be prevalent drivers of their host ecology as they modify their phenotypes and interspecific interactions. These virus-mediated ecological effects may have consequences on enemies foraging strategies as well as trophic webs dynamics and structure
Intraspecific difference among herbivore lineages and their host-plant specialization drive the strength of trophic cascades
No full text<p>Dataset from the publication Intraspecific difference among herbivore lineages and their host-plant specialization drive the strength of trophic cascades</p>
Effet de la température sur les interactions trophiques et intraguildes au sein d'un système plante-herbivore-ennemis naturels : modélisation et approches expérimentales
No full textBien que les effets des changements climatiques sur les individus d'une espèce soient largement connus, les connaissances demeurent limitées quant aux conséquences sur les interactions trophiques. Notre étude s'intéresse aux effets de la température sur un système biologique plante-puceron-coccinelle. Nous avons modélisé les interactions trophiques et réalisé des expériences empiriques afin de caractériser l'effet de la température sur les composantes du système biologique étudié. Nos modèles et résultats mettent en évidence que le taux de prédation et la fréquence des interactions intraguildes augmentent avec la température, atteignent un maximum puis décroissent à température élevée. Conformément aux prédictions du modèle, la prédation intraguilde diminue lorsque la densité de puceron augmente. Nos résultats démontrent aussi que le système biologique résiste mieux aux pics de température en présence de coccinelles qu'en leur absence. Notre étude souligne l'importance de considérer la température dans les interactions trophiques puisqu'elle influence le comportement des organismes et la fréquence de leur interaction.Although the effects of climate change on individual organisms or populations have been well documented, our understanding about their consequences on trophic interactions remains limited. We investigated the effects of temperature on complex interactions in a plant-aphid-ladybeetle system. We combined models and laboratory experiments to characterize the effects of temperature on components of our biological system. We found that predation rate and intraguild interactions increase with temperature, reach a maximum, and then decrease at higher temperature. According to model predictions, intraguild predation decreases when aphid density increases. We also observed that the food chain is more resistant to temperature peaks when ladybeetles are included in the system than when they are absent. Our study highlights the importance of considering temperature in trophic and guild interactions since it influences the behavior of organisms as well as the frequency of interactions
Aperçu éditorial: Changement global: intégrer les conséquences écologiques et évolutives à travers le temps et l'espace
No full text[Departement_IRSTEA]Eaux [ADD1_IRSTEA]Dynamique et fonctionnement des écosystèmesInternational audienceHuman activities have changed ecosystems at local and global scales. These changes include altered climate, habitat loss and fragmentation, species invasions, land use change, pollution, and pesticides [1]. These changes threatens many species and affects biodiversity and ecosystem functions and services through multiple side effects [2, 3, 4]. Insects are of major importance for ecology, economy, health, and alimentation and their populations are declining worldwide [5]. Understanding the impacts of global change drivers on the diversity, abundance, and functions of insect species is thus an urgent scientific and societal challenge. However, addressing this challenge is difficult for several reasons. First, species are embedded within communities and the effects of global change drivers on a single species thus depend on their direct and indirect effects mediated by species interactions [6,7]. Second, evolutionary, epigenetic and plastic phenotypic responses to environmental change affect the spatial and temporal distributions of phenotypes which can modulate the speed of evolutionary adaptation as well as species' functions and interactions [8, 9, 10]. Third, humans can strongly influence species dispersal by fragmenting natural habitats or mediating insect dispersal trough long distances [11,12]. Change in insect dispersal can have important consequences on, for instance, their meta-population dynamics or the establishment of exotic invasive species. Fourth, global change drivers can interact in space and time and their combined effects can be additive, synergistic or antagonist, which adds another layer of difficulty when addressing or predicting multiple driver effects on insects [13]. We propose that analysing issues of global change from a perspective addressing these fourth points will lead to a fully integrative understanding of the ecological and evolutionary consequences of global change across time and space. However, developing a comprehensive understanding of how all this plays out remains an important research frontier. We thus have assembled 12 contributions that each tackle a component of what we believe is needed to integrate the ecological and evolutionary consequences of global change across time and space. We hope that this issue will advance a new, concerted research effort that can help developing a more comprehensive perspective on how global change affects ecological systems. Such comprehensive perspective is certainly needed to preserve biodiversity, manage natural resources, and maintain key ecosystem services such as pollination and the control of agricultural pests and vector diseases
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