scholarly journals Unravelling Darwin's entangled bank: architecture and robustness of mutualistic networks with multiple interaction types

2016 ◽  
Vol 283 (1843) ◽  
pp. 20161564 ◽  
Author(s):  
Wesley Dáttilo ◽  
Nubia Lara-Rodríguez ◽  
Pedro Jordano ◽  
Paulo R. Guimarães ◽  
John N. Thompson ◽  
...  
Keyword(s):  
Evolutionary Dynamics ◽  
Plant Protection ◽  
Interaction Network ◽  
Ecological Communities ◽  
Multiple Forms ◽  
Interacting Species ◽  
Interactive Species ◽  
Mutualistic Networks ◽  
Multiple Interaction

Trying to unravel Darwin's entangled bank further, we describe the architecture of a network involving multiple forms of mutualism (pollination by animals, seed dispersal by birds and plant protection by ants) and evaluate whether this multi-network shows evidence of a structure that promotes robustness. We found that species differed strongly in their contributions to the organization of the multi-interaction network, and that only a few species contributed to the structuring of these patterns. Moreover, we observed that the multi-interaction networks did not enhance community robustness compared with each of the three independent mutualistic networks when analysed across a range of simulated scenarios of species extinction. By simulating the removal of highly interacting species, we observed that, overall, these species enhance network nestedness and robustness, but decrease modularity. We discuss how the organization of interlinked mutualistic networks may be essential for the maintenance of ecological communities, and therefore the long-term ecological and evolutionary dynamics of interactive, species-rich communities. We suggest that conserving these keystone mutualists and their interactions is crucial to the persistence of species-rich mutualistic assemblages, mainly because they support other species and shape the network organization.

scholarly journals Eco-evolutionary feedbacks promote fluctuating selection and long-term stability of antagonistic networks

2018 ◽  
Vol 285 (1874) ◽  
pp. 20172596 ◽  
Author(s):  
Cecilia Siliansky de Andreazzi ◽  
Paulo R. Guimarães ◽  
Carlos J. Melián
Keyword(s):  
Temporal Variation ◽  
Evolutionary Dynamics ◽  
Species Interaction ◽  
Fluctuating Selection ◽  
Term Stability ◽  
Long Term Stability ◽  
Interacting Species ◽  
Species Abundances ◽  
Antagonistic Interactions

Studies have shown the potential for rapid adaptation in coevolving populations and that the structure of species interaction networks can modulate the vulnerability of ecological systems to perturbations. Although the feedback loop between population dynamics and coevolution of traits is crucial for understanding long-term stability in ecological assemblages, modelling eco-evolutionary dynamics in species-rich assemblages is still a challenge. We explore how eco-evolutionary feedbacks influence trait evolution and species abundances in 23 empirical antagonistic networks. We show that, if selection due to antagonistic interactions is stronger than other selective pressures, eco-evolutionary feedbacks lead to higher mean species abundances and lower temporal variation in abundances. By contrast, strong selection of antagonistic interactions leads to higher temporal variation of traits and on interaction strengths. Our results present a theoretical link between the study of the species persistence and coevolution in networks of interacting species, pointing out the ways by which coevolution may decrease the vulnerability of species within antagonistic networks to demographic fluctuation.

scholarly journals Phenological variation in annual timing of hibernation and breeding in nearby populations of Arctic ground squirrels

2010 ◽  
Vol 278 (1716) ◽  
pp. 2369-2375 ◽  
Author(s):  
Michael J. Sheriff ◽  
G. Jim Kenagy ◽  
Melanie Richter ◽  
Trixie Lee ◽  
Øivind Tøien ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Ground Squirrels ◽  
Ecological Communities ◽  
Physiological Mechanisms ◽  
Interacting Species ◽  
Trade Offs ◽  
Phenological Shifts ◽  
Arctic Ground Squirrels ◽  
Northern Alaska

Ecologists need an empirical understanding of physiological and behavioural adjustments that animals can make in response to seasonal and long-term variations in environmental conditions. Because many species experience trade-offs between timing and duration of one seasonal event versus another and because interacting species may also shift phenologies at different rates, it is possible that, in aggregate, phenological shifts could result in mismatches that disrupt ecological communities. We investigated the timing of seasonal events over 14 years in two Arctic ground squirrel populations living 20 km apart in Northern Alaska. At Atigun River, snow melt occurred 27 days earlier and snow cover began 17 days later than at Toolik Lake. This spatial differential was reflected in significant variation in the timing of most seasonal events in ground squirrels living at the two sites. Although reproductive males ended seasonal torpor on the same date at both sites, Atigun males emerged from hibernation 9 days earlier and entered hibernation 5 days later than Toolik males. Atigun females emerged and bred 13 days earlier and entered hibernation 9 days earlier than those at Toolik. We propose that this variation in phenology over a small spatial scale is likely generated by plasticity of physiological mechanisms that may also provide individuals the ability to respond to variation in environmental conditions over time.

scholarly journals Macroevolutionary imprints on the assembly of frugivory networks

2020 ◽  
Author(s):  
Gustavo Burin ◽  
Paulo R. Guimarães ◽  
Tiago B. Quental
Keyword(s):  
Interaction Network ◽  
Ecological Networks ◽  
Species Number ◽  
Ecological Communities ◽  
Biological Interactions ◽  
Deep Time ◽  
Interacting Species ◽  
History Of ◽  
Current Interaction ◽  
Biodiversity Changes

Biological interactions are a key aspect of ecological communities (Delmas et al., 2018). Current interaction network structures are snapshots of dynamic processes of community assembly (Thompson, 2005), and represent the product of the evolutionary history of interacting species over millions of years. Thus, assessing the deep time mechanisms affecting the assembly of ecological networks are key to better understand biodiversity changes in broader time scales (Jablonski, 2008). Here we integrate tools from macroevolutionary studies with network science to show that more central species in frugivory networks belong to lineages with higher macroevolutionary stability. This association is more pronounced in warmer, wetter, less seasonal environments, which highlights the role of environmental factors in shaping ecological networks. Furthermore, our results suggest that these environments possess a more diverse (either in species number or ecology) assemblage of species that can be sorted during network assembly. Lastly, we found evidence that the macro-evolutionary contribution to network stability changes in geographical space. This reinforces the idea that the macroevolutionary sorting mechanism acts at the regional pool of species, rather than selecting absolute paces of diversification. Hence our results suggest an interplay between ecological roles and diversification regimes in shaping the fate of lineages of plants and seed dispersing birds.

scholarly journals Environmental variability and phenology evolution: impacts of climate change and spring onset on reproductive timing in a small mammal

2018 ◽  
Author(s):  
Easton R White ◽  
Kalle Parvinen ◽  
Ulf Dieckmann
Keyword(s):  
Climate Change ◽  
Evolutionary Dynamics ◽  
Environmental Variability ◽  
Long Term Effects ◽  
Timing Of Reproduction ◽  
Juvenile Mortality ◽  
Interacting Species ◽  
Ochotona Collaris ◽  
The Mean

The phenology, or timing of life history events, of organisms affects both ecological and evolutionary dynamics. Recent work has illustrated the effects of climate change on the phenology for many species. Changing selective pressures on phenology can have consequences for species if the reliability of phenological cues decreases or if climate change affects interacting species differentially. There are now numerous examples, in which earlier mean timing of spring has selected for earlier phenology of organisms. However, much less is known about how changes in the variability of spring — and consequently the reliability of cues — might affect species. We built a general model of animal population dynamics to study both the ecology and evolution of phenological events under climate change. We parameterized this model for a population of the collared pika (Ochotona collaris) found in the Yukon, Canada. In line with past work, we show that an earlier timing of spring snowmelt will select for an earlier timing of reproduction. In addition, we show that variability in the onset of spring also selects for earlier reproduction. However, evolution or plasticity in juvenile mortality, due to late snowmelt, can lead to later reproduction. These results highlight the importance of looking at the variability, and not only the mean, in spring onset. The specific relationship between the mean and variability of spring onset coupled with the ability of a population to be plastic or adaptable will determine the long-term effects of climate change on the phenology of species.

scholarly journals Environmental variability and phenology evolution: impacts of climate change and spring onset on reproductive timing in a small mammal

2018 ◽  
Author(s):  
Easton R White ◽  
Kalle Parvinen ◽  
Ulf Dieckmann
Keyword(s):  
Climate Change ◽  
Evolutionary Dynamics ◽  
Environmental Variability ◽  
Long Term Effects ◽  
Timing Of Reproduction ◽  
Juvenile Mortality ◽  
Interacting Species ◽  
Ochotona Collaris ◽  
The Mean

The phenology, or timing of life history events, of organisms affects both ecological and evolutionary dynamics. Recent work has illustrated the effects of climate change on the phenology for many species. Changing selective pressures on phenology can have consequences for species if the reliability of phenological cues decreases or if climate change affects interacting species differentially. There are now numerous examples, in which earlier mean timing of spring has selected for earlier phenology of organisms. However, much less is known about how changes in the variability of spring — and consequently the reliability of cues — might affect species. We built a general model of animal population dynamics to study both the ecology and evolution of phenological events under climate change. We parameterized this model for a population of the collared pika (Ochotona collaris) found in the Yukon, Canada. In line with past work, we show that an earlier timing of spring snowmelt will select for an earlier timing of reproduction. In addition, we show that variability in the onset of spring also selects for earlier reproduction. However, evolution or plasticity in juvenile mortality, due to late snowmelt, can lead to later reproduction. These results highlight the importance of looking at the variability, and not only the mean, in spring onset. The specific relationship between the mean and variability of spring onset coupled with the ability of a population to be plastic or adaptable will determine the long-term effects of climate change on the phenology of species.

scholarly journals Long-Term Cocirculation of Two Strains of Pepino Mosaic Virus in Tomato Crops and Its Effect on Population Genetic Variability

2020 ◽  
Vol 110 (1) ◽  
pp. 49-57 ◽  
Author(s):  
C. Alcaide ◽  
M. P. Rabadán ◽  
M. Juárez ◽  
P. Gómez
Keyword(s):  
Genetic Variability ◽  
Mosaic Virus ◽  
Evolutionary Dynamics ◽  
Geographical Area ◽  
Viral Fitness ◽  
Mixed Infections ◽  
Supporting Evidence ◽  
Pepino Mosaic Virus ◽  
Nucleotide Variability

Mixed viral infections are common in plants, and the evolutionary dynamics of viral populations may differ depending on whether the infection is caused by single or multiple viral strains. However, comparative studies of single and mixed infections using viral populations in comparable agricultural and geographical locations are lacking. Here, we monitored the occurrence of pepino mosaic virus (PepMV) in tomato crops in two major tomato-producing areas in Murcia (southeastern Spain), supporting evidence showing that PepMV disease-affected plants had single infections of the Chilean 2 (CH2) strain in one area and the other area exhibited long-term (13 years) coexistence of the CH2 and European (EU) strains. We hypothesized that circulating strains of PepMV might be modulating the differentiation between them and shaping the evolutionary dynamics of PepMV populations. Our phylogenetic analysis of 106 CH2 isolates randomly selected from both areas showed a remarkable divergence between the CH2 isolates, with increased nucleotide variability in the geographical area where both strains cocirculate. Furthermore, the potential virus–virus interaction was studied further by constructing six full-length infectious CH2 clones from both areas, and assessing their viral fitness in the presence and absence of an EU-type isolate. All CH2 clones showed decreased fitness in mixed infections and although complete genome sequencing indicated a nucleotide divergence of those CH2 clones by area, the magnitude of the fitness response was irrespective of the CH2 origin. Overall, these results suggest that although agroecological cropping practices may be particularly important for explaining the evolutionary dynamics of PepMV in tomato crops, the cocirculation of both strains may have implications on the genetic variability of PepMV populations.

The elicitor protein BcIEB1 and the derived peptide ieb35 provide long‐term plant protection

2020 ◽  
Vol 69 (5) ◽  
pp. 807-817 ◽  
Author(s):  
Alicia Pérez‐Hernández ◽  
Mario González ◽  
Celedonio González ◽  
Nélida Brito
Keyword(s):  
Plant Protection

scholarly journals Dinosaurs in decline tens of millions of years before their final extinction

2016 ◽  
Vol 113 (18) ◽  
pp. 5036-5040 ◽  
Author(s):  
Manabu Sakamoto ◽  
Michael J. Benton ◽  
Chris Venditti
Keyword(s):  
Mass Extinction ◽  
Marked Reduction ◽  
Evolutionary Dynamics ◽  
General Pattern ◽  
Extinction Rate ◽  
Catastrophic Event ◽  
Extinction Event ◽  
Mass Extinction Event ◽  
First Time

Whether dinosaurs were in a long-term decline or whether they were reigning strong right up to their final disappearance at the Cretaceous–Paleogene (K-Pg) mass extinction event 66 Mya has been debated for decades with no clear resolution. The dispute has continued unresolved because of a lack of statistical rigor and appropriate evolutionary framework. Here, for the first time to our knowledge, we apply a Bayesian phylogenetic approach to model the evolutionary dynamics of speciation and extinction through time in Mesozoic dinosaurs, properly taking account of previously ignored statistical violations. We find overwhelming support for a long-term decline across all dinosaurs and within all three dinosaurian subclades (Ornithischia, Sauropodomorpha, and Theropoda), where speciation rate slowed down through time and was ultimately exceeded by extinction rate tens of millions of years before the K-Pg boundary. The only exceptions to this general pattern are the morphologically specialized herbivores, the Hadrosauriformes and Ceratopsidae, which show rapid species proliferations throughout the Late Cretaceous instead. Our results highlight that, despite some heterogeneity in speciation dynamics, dinosaurs showed a marked reduction in their ability to replace extinct species with new ones, making them vulnerable to extinction and unable to respond quickly to and recover from the final catastrophic event.

The Textual Evolution of the Ottoman Şeyhülislams’ Fetvas: A Cross-Corpora Computational Analysis

Der Islam ◽  
2021 ◽  
Vol 98 (2) ◽  
pp. 516-545
Author(s):  
Boğaç Ergene ◽  
Atabey Kaygun
Keyword(s):  
Seventeenth Century ◽  
Computational Analysis ◽  
Computational Techniques ◽  
Close Reading ◽  
Institutional Evolution ◽  
Multiple Forms ◽  
Term Evolution ◽  
Speed Up ◽  
Over Time

Abstract In this article, we use a mix of computational techniques to identify textual shifts in the Ottoman şeyhülislams’ fetvas between the sixteenth and twentieth centuries. Our analysis, supplemented by a close reading of these texts, indicates that the fetvas underwent multiple forms of transformation, a consequence of the institutional evolution of the şeyhülislam’s fetva office (fetvahane) that aimed to speed up and streamline the production of the fetvas: over time, the texts appropriated a more uniform character and came to contain shorter responses. In the compositions of the questions, we identified many “trigger terms” that facilitated reflexive responses independent of the fetvas’ jurisprudential contexts, a tendency that became stronger after the second half of the seventeenth century. In addition, we propose in the article a methodology that measures the relative strengths of textual and conceptual links among the fetva corpora of various Ottoman şeyhülislams. This analysis informs us about possible paths of long-term evolution of this genre of jurisprudential documents.

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.

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