scholarly journals The role of indirect effects in coevolution as mutualism transitions into antagonism

2021 ◽  
Author(s):  
Fernando Pedraza ◽  
Hanlun Liu ◽  
Klementyna A. Gawecka ◽  
Jordi Bascompte
Keyword(s):  
Global Change ◽  
Evolutionary Theory ◽  
Indirect Effects ◽  
Species Interactions ◽  
Antagonistic Selection ◽  
Combine Network ◽  
Mutualistic Networks ◽  
Interaction Types ◽  
Tight Integration

Species interactions have evolved from antagonistic to mutualistic and back several times throughout life's history. Yet, it is unclear how changes in the type of interaction between species alter the coevolutionary dynamics of entire communities. This is a pressing matter, as transitions from mutualisms to antagonisms may be becoming more common with human-induced global change. Here, we combine network and evolutionary theory to simulate how shifts in interaction types alter the coevolution of empirical communities. We show that as mutualistic networks shift to antagonistic, selection imposed by direct partners begins to outweigh that imposed by indirect partners. This weakening of indirect effects is associated with communities losing their tight integration of traits and increasing their rate of adaptation. The above changes are more pronounced when specialist consumers are the first species to switch to antagonism. A shift in the outcome of species' interactions may therefore reverberate across communities and alter the direction and speed of coevolution.

scholarly journals Interactions between Climate and Nutrient Cycles on Forest Response to Global Change: The Role of Mixed Forests

Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 609 ◽  
Author(s):  
Ester González de Andrés
Keyword(s):  
Climate Change ◽  
Global Change ◽  
Environmental Conditions ◽  
Species Interactions ◽  
N Deposition ◽  
Elemental Ratios ◽  
Nutrient Mineralization ◽  
Carbon Dioxide Co2 ◽  
The Impact

Forest ecosystems are undergoing unprecedented changes in environmental conditions due to global change impacts. Modification of global biogeochemical cycles of carbon and nitrogen, and the subsequent climate change are affecting forest functions at different scales, from physiology and growth of individual trees to cycling of nutrients. This review summarizes the present knowledge regarding the impact of global change on forest functioning not only with respect to climate change, which is the focus of most studies, but also the influence of altered nitrogen cycle and the interactions among them. The carbon dioxide (CO2) fertilization effect on tree growth is expected to be constrained by nutrient imbalances resulting from high N deposition rates and the counteractive effect of increasing water deficit, which interact in a complex way. At the community level, responses to global change are modified by species interactions that may lead to competition for resources and/or relaxation due to facilitation and resource partitioning processes. Thus, some species mixtures can be more resistant to drought than their respective pure forests, albeit it depends on environmental conditions and species’ functional traits. Climate change and nitrogen deposition have additional impacts on litterfall dynamics, and subsequent decomposition and nutrient mineralization processes. Elemental ratios (i.e., stoichiometry) are associated with important ecosystem traits, including trees’ adaptability to stress or decomposition rates. As stoichiometry of different ecosystem components are also influenced by global change, nutrient cycling in forests will be altered too. Therefore, a re-assessment of traditional forest management is needed in order to cope with global change. Proposed silvicultural systems emphasize the key role of diversity to assure multiple ecosystem services, and special attention has been paid to mixed-species forests. Finally, a summary of the patterns and underlying mechanisms governing the relationships between diversity and different ecosystems functions, such as productivity and stability, is provided.

scholarly journals Influence of the Electrolyte Salt Concentration on DNA Detection with Graphene Transistors

Biosensors ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 24
Author(s):  
Agnes Purwidyantri ◽  
Telma Domingues ◽  
Jérôme Borme ◽  
Joana Rafaela Guerreiro ◽  
Andrey Ipatov ◽  
...  
Keyword(s):  
Phosphate Buffer ◽  
Species Interactions ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Limit Of Detection ◽  
Debye Length ◽  
Intermolecular Forces ◽  
Single Layer Graphene ◽  
Dna Adsorption

Liquid-gated Graphene Field-Effect Transistors (GFET) are ultrasensitive bio-detection platforms carrying out the graphene’s exceptional intrinsic functionalities. Buffer and dilution factor are prevalent strategies towards the optimum performance of the GFETs. However, beyond the Debye length (λD), the role of the graphene-electrolytes’ ionic species interactions on the DNA behavior at the nanoscale interface is complicated. We studied the characteristics of the GFETs under different ionic strength, pH, and electrolyte type, e.g., phosphate buffer (PB), and phosphate buffer saline (PBS), in an automatic portable built-in system. The electrostatic gating and charge transfer phenomena were inferred from the field-effect measurements of the Dirac point position in single-layer graphene (SLG) transistors transfer curves. Results denote that λD is not the main factor governing the effective nanoscale screening environment. We observed that the longer λD was not the determining characteristic for sensitivity increment and limit of detection (LoD) as demonstrated by different types and ionic strengths of measuring buffers. In the DNA hybridization study, our findings show the role of the additional salts present in PBS, as compared to PB, in increasing graphene electron mobility, electrostatic shielding, intermolecular forces and DNA adsorption kinetics leading to an improved sensitivity.

Deductive Hedonism and the Anxiety of Influence

Utilitas ◽  
2000 ◽  
Vol 12 (3) ◽  
pp. 329-346 ◽  
Author(s):  
D. Weinstein
Keyword(s):  
Evolutionary Theory ◽  
Moral Rights ◽  
The Real ◽  
Herbert Spencer ◽  
Anxiety Of Influence

This paper examines the undervalued role of Herbert Spencer in Sidgwick's thinking. Sidgwick recognized Spencer's utilitarianism, but criticized him on the ground that he tried to deduce utilitarianism from evolutionary theory. In analysing these criticisms, this paper concludes that Spencer's deductive methodology was in fact closer to Sidgwick's empiricist position than Sidgwick realized. The real source of Sidgwick's unhappiness withSpencer lies with the substance of Spencer's utilitarianism, namely its espousal of indefeasible moral rights.

From Victims to Perpetrators of Bullying: The Role of Irrational Cognitions, Externalizing Problems, and Parental Attachment

2021 ◽  
pp. 088626052110435
Author(s):  
Raluca Balan ◽  
Anca Dobrean ◽  
Robert Balazsi
Keyword(s):  
Public Schools ◽  
Path Analysis ◽  
Indirect Effects ◽  
Externalizing Problems ◽  
Parental Attachment ◽  
Bullying Victimization ◽  
Indirect Pathway ◽  
Bullying Perpetration ◽  
Interaction Terms

The transition from bullying victimization to bullying perpetration is well documented in the literature. However, the mechanisms linking bullying victimization to perpetration are not fully understood. The main aim of the current study was to conduct a preliminary research investigating the indirect effects of youths bullying victimization on bullying perpetration through irrational cognitions and externalizing problems. The second aim of the study was to explore the moderating role of the type of parental attachment (secure vs. insecure) in the proposed model in explaining the association of bullying victimization and bullying perpetration. Data were collected from 269 adolescents (11-15 years; M = 11.98, SD = .68), enrolled in middle public schools from Romania. Path analysis and moderated path analysis were conducted to explore the direct and indirect effects and moderating effects, respectively. Study findings indicate that bullying victimization was indirectly related to bullying perpetration separately through youths’ irrational cognition as well as through externalizing problems. The serial indirect pathway from victimization to perpetration through irrational cognitions leading further to externalizing problems was also significant. However, the type of attachment that adolescents reported having toward their parents failed to moderate the indirect pathways, since all the interaction terms were nonsignificant. These findings advance the field prevention and intervention by identifying irrational cognitions and externalizing problems as important targets that anti-bullying programs should address to stop the transition from victims of bullying to perpetrators.

Subdimensions of total rewards satisfaction and creativity among R&D employees: a moderated mediation model

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zhenyuan Wang ◽  
Jianghong Du ◽  
Herman H.M. Tse ◽  
Jun Gu ◽  
Hui Meng ◽  
...  
Keyword(s):  
Work Stress ◽  
Work Engagement ◽  
Indirect Effects ◽  
Moderated Mediation ◽  
Relative Importance ◽  
Mediation Model ◽  
Content Type ◽  
Moderated Mediation Model ◽  
Total Rewards

PurposeThis study aims to explore the relative importance of the subdimensions of total rewards satisfaction in predicting research and development (R&D) employee creativity. In addition, the study examines the indirect effects of the subdimensions of total rewards satisfaction on creativity via work engagement and the moderating role of challenge-related work stress in the first stage.Design/methodology/approachA two-wave design was used, in which total rewards satisfaction and challenge-related work stress were measured in the first wave. Work engagement and creativity were measured in the second wave. Dominance analysis and the latent moderated mediation model were used for the data analyses.FindingsThe analyses show that nonfinancial rewards satisfaction completely dominates indirect and direct financial rewards satisfaction when predicting creativity. Indirect financial rewards satisfaction completely dominates direct financial rewards satisfaction when predicting creativity. Work engagement mediates the relationships between the subdimensions of total rewards satisfaction and creativity. Challenge-related work stress moderates the relationships between the subdimensions of total rewards satisfaction and work engagement and the indirect effects of the subdimensions of total rewards satisfaction on creativity via work engagement.Practical implicationsThe results imply that managers should set challenge demands for R&D employees and try to improve their total rewards satisfaction, especially their nonfinancial and indirect financial rewards satisfaction, for them to be more creative.Originality/valueThis empirical study contributes to the literature by comparing the relative importance of the different dimensions of total rewards satisfaction in predicting creativity. The study also clarifies how (through work engagement) and when (based on challenge-related work stress) the subdimensions of total rewards satisfaction are positively related to R&D employees' creativity.

scholarly journals Using insect natural history collections to study global change impacts: challenges and opportunities

2018 ◽  
Vol 374 (1763) ◽  
pp. 20170405 ◽  
Author(s):  
Heather M. Kharouba ◽  
Jayme M. M. Lewthwaite ◽  
Rob Guralnick ◽  
Jeremy T. Kerr ◽  
Mark Vellend
Keyword(s):  
Natural History ◽  
Global Change ◽  
Global Changes ◽  
Genomic Information ◽  
Theme Issue ◽  
The Past ◽  
Natural History Collections ◽  
Global Change Research ◽  
Challenges And Opportunities

Over the past two decades, natural history collections (NHCs) have played an increasingly prominent role in global change research, but they have still greater potential, especially for the most diverse group of animals on Earth: insects. Here, we review the role of NHCs in advancing our understanding of the ecological and evolutionary responses of insects to recent global changes. Insect NHCs have helped document changes in insects' geographical distributions, phenology, phenotypic and genotypic traits over time periods up to a century. Recent work demonstrates the enormous potential of NHCs data for examining insect responses at multiple temporal, spatial and phylogenetic scales. Moving forward, insect NHCs offer unique opportunities to examine the morphological, chemical and genomic information in each specimen, thus advancing our understanding of the processes underlying species’ ecological and evolutionary responses to rapid, widespread global changes. This article is part of the theme issue ‘Biological collections for understanding biodiversity in the anthropocene’.

scholarly journals The geographic mosaic of coevolution in mutualistic networks

2018 ◽  
Vol 115 (47) ◽  
pp. 12017-12022 ◽  
Author(s):  
Lucas P. Medeiros ◽  
Guilherme Garcia ◽  
John N. Thompson ◽  
Paulo R. Guimarães
Keyword(s):  
Gene Flow ◽  
Species Interactions ◽  
Analytical Approximation ◽  
Spatial Processes ◽  
Geographic Mosaic ◽  
Generalist Species ◽  
Interacting Species ◽  
Adaptive Landscapes ◽  
Surprising Effect ◽  
Mutualistic Networks

Ecological interactions shape adaptations through coevolution not only between pairs of species but also through entire multispecies assemblages. Local coevolution can then be further altered through spatial processes that have been formally partitioned in the geographic mosaic theory of coevolution. A major current challenge is to understand the spatial patterns of coadaptation that emerge across ecosystems through the interplay between gene flow and selection in networks of interacting species. Here, we combine a coevolutionary model, network theory, and empirical information on species interactions to investigate how gene flow and geographical variation in selection affect trait patterns in mutualistic networks. We show that gene flow has the surprising effect of favoring trait matching, especially among generalist species in species-rich networks typical of pollination and seed dispersal interactions. Using an analytical approximation of our model, we demonstrate that gene flow promotes trait matching by making the adaptive landscapes of different species more similar to each other. We use this result to show that the progressive loss of gene flow associated with habitat fragmentation may undermine coadaptation in mutualisms. Our results therefore provide predictions of how spatial processes shape the evolution of species-rich interactions and how the widespread fragmentation of natural landscapes may modify the coevolutionary process.

scholarly journals The Structural Basis of Repertoire Shift in an Immune Response to Phosphocholine

2000 ◽  
Vol 191 (12) ◽  
pp. 2101-2112 ◽  
Author(s):  
McKay Brown ◽  
Maria A. Schumacher ◽  
Gregory D. Wiens ◽  
Richard G. Brennan ◽  
Marvin B. Rittenberg
Keyword(s):  
Immune Response ◽  
Light Chain ◽  
Indirect Effects ◽  
Somatic Mutations ◽  
Variable Region ◽  
Primary Response ◽  
Structural Basis ◽  
Antibody Repertoire ◽  
High Affinity

The immune response to phosphocholine (PC)–protein is characterized by a shift in antibody repertoire as the response progresses. This change in expressed gene combinations is accompanied by a shift in fine specificity toward the carrier, resulting in high affinity to PC–protein. The somatically mutated memory hybridoma, M3C65, possesses high affinity for PC–protein and the phenyl-hapten analogue, p-nitrophenyl phosphocholine (NPPC). Affinity measurements using related PC–phenyl analogues, including peptides of varying lengths, demonstrate that carrier determinants contribute to binding affinity and that somatic mutations alter this recognition. The crystal structure of an M3C65–NPPC complex at 2.35-Å resolution allows evaluation of the three light chain mutations that confer high-affinity binding to NPPC. Only one of the mutations involves a contact residue, whereas the other two have indirect effects on the shape of the combining site. Comparison of the M3C65 structure to that of T15, an antibody dominating the primary response, provides clear structural evidence for the role of carrier determinants in promoting repertoire shift. These two antibodies express unrelated variable region heavy and light chain genes and represent a classic example of the effect of repertoire shift on maturation of the immune response.

Sign in / Sign up

Export Citation Format

Share Document