scholarly journals Stable coexistence in plant-pollinator-herbivore communities requires balanced mutualistic vs antagonistic interactions

2021 ◽  
Author(s):  
Youssef Yacine ◽  
Nicolas Loeuille

Ecological communities consist of multiple species interacting in diverse ways. Understanding the mechanisms supporting coexistence requires accounting for such a diversity. Because most works focus either on mutualism or predation, how pollination and herbivory interactively determine the stable coexistence in plant-pollinator-herbivore communities is still poorly understood. Studying the typical three-species module of such communities, we determine the conditions allowing stable coexistence then investigate how its maintenance constrains the relative interaction strengths. Our results show that coexistence is possible if pollination is sufficiently strong relative to herbivory, while its stability is possible if herbivory is sufficiently strong relative to pollination. A balance between pollination and herbivory is therefore required. Interestingly, shared preferences for plant phenotypes, that would favor such balance, have been frequently reported in the empirical literature. The identified ecological trade-off between attracting pollinators and deterring herbivores therefore also appears as an emergent property of stable plant-pollinator-herbivore communities.


Author(s):  
Rong Wang ◽  
Yang Yang ◽  
Yi Jing ◽  
Simon T. Segar ◽  
Yu Zhang ◽  
...  


2017 ◽  
Author(s):  
Sergi Valverde ◽  
Santiago F. Elena ◽  
Ricard Solé

Ecological networks, both displaying mutualistic or antagonistic interactions, seem to share common structural traits: the presence of nestedness and modularity. A variety of model approaches and hypothesis have been formulated concerning the significance and implications of these properties. In phage-bacteria bipartite infection networks, nestedness seems to be the rule in many different contexts. Modeling the coevolution of a diverse virus-host ensemble is a difficult task, given the dimensionality and multi parametric nature of a standard continuous approximation. Here we show that this can actually be overcome by using a simple model of coevolving digital genomes on a spatial lattice and having exactly the same properties, i.e. a genome-independent fitness associated to fixed growth and death parameters. A matching allele model of phage-virus recognition rule is enough to generate a complex, diverse ecosystem with heterogeneous patterns of interaction and nestedness, provided that interactions take place under a spatially-constrained setting. It is found that nestedness seems to be an emergent property of the coevolutionary dynamics. Our results indicate that the enhanced diversity resulting from localized interactions strongly promotes the presence of nested infection matrices.



2020 ◽  
Vol 22 (02) ◽  
pp. 2040007
Author(s):  
Dushyant Kumar ◽  
Prabal Roy Chowdhury

We examine a dynamic two-stage incumbent-challenger model of internal conflict, where the government, i.e., the incumbent, is in power, while the rebel challenges the government in a bid to capture state power. The central issue is the trade-off between development and security-based measures in countering such rebellion activity. We find that while an exogenous increase in development decreases the level of rebellion activity, it increases the level of security-based measures by the government whenever the rebel is ‘dominant’ to begin with. Further, if the rebel is dominant, then, with the rebel becoming stronger (i.e., becoming more cost efficient), the level of rebel activity increases, while the security-based measures by the government is lowered. Thus, our analysis suggests that the trade-off is a nuanced one. This framework also allows us to reconcile some divergent results in the empirical literature regarding the effect of development works on conflict.



2010 ◽  
Vol 221 (3) ◽  
pp. 453-458 ◽  
Author(s):  
Nicholas S. Fabina ◽  
Karen C. Abbott ◽  
R.Tucker Gilman


2019 ◽  
Author(s):  
Heather M. Briggs ◽  
Carolyn A. Ayers ◽  
Paul R. Armsworth ◽  
Berry J. Brosi

AbstractGiven ongoing pollinator declines, it is important to understand the dynamics of linked extinctions of plants driven by pollinator extinctions. Topological robustness models focused on this question suggest relatively high robustness of plant species to pollinator species extinctions. Still, existing robustness models typically assume that all interactions in plant-pollinator networks are positive, which is clearly not always the case. For example, many pollinators remove floral resources with-out transferring pollen, or even damage floral structures in the case of nectar robbing. Here we introduce antagonistic interactions into plant-pollinator networks and assess the resilience of plant communities to pollinator species losses. Incorporating antagonistic interactions leads to lower network robustness, i.e. an increased rate of plant species loss (as compared to networks with only mutualistic interactions) in empirical plant-pollinator networks. In conjunction with extinction order, the addition of increasingly antagonistic interactions was idiosyncratic in that it did not always magnify the effects of extinction order across the three networks. These results underscore the importance of considering the full spectrum of interaction outcomes when assessing robustness to coextinctions in plant-pollinator networks, as well as other ecological systems.



2020 ◽  
Author(s):  
Paul J. CaraDonna ◽  
Nickolas M. Waser

AbstractEcological communities consist of species that are joined in complex networks of interspecific interaction. The interactions that networks depict often form and dissolve rapidly, but this temporal variation is not well integrated into our understanding of the causes and consequences of network structure. If interspecific interactions exhibit temporal flexibility across time periods over which organisms co-occur, then the emergent structure of the corresponding network may also be temporally flexible, something that a temporally-static perspective would miss. Here, we use an empirical system to examine short-term flexibility in network structure (connectance, nestedness, and specialization), and in individual species interactions that contribute to that structure. We investigated weekly plant-pollinator networks in a subalpine ecosystem across three summer growing seasons. To link the interactions of individual species to properties of their networks, we examined weekly temporal variation in species’ contributions to network structure. As a test of the potential robustness of networks to perturbation, we also simulated the random loss of species from weekly networks. We then compared the properties of weekly networks to the properties of cumulative networks that aggregate field observations over each full season. A week-to-week view reveals considerable flexibility in the interactions of individual species and their contributions to network structure. For example, species that would be considered relatively generalized across their entire activity period may be much more specialized at certain times, and at no point as generalized as the cumulative network may suggest. Furthermore, a week-to-week view reveals corresponding temporal flexibility in network structure and potential robustness throughout each summer growing season. We conclude that short-term flexibility in species interactions leads to short-term variation in network properties, and that a season-long, cumulative perspective may miss important aspects of the way in which species interact, with implications for understanding their ecology, evolution, and conservation.



2021 ◽  
Author(s):  
Pengjuan Zu ◽  
Karina Boege ◽  
Ek del Val ◽  
Meredith Christine Schuman ◽  
Phil Stevenson ◽  
...  

Zu et al. 2020 (1) proposed a simple, parameter-free, information-arms-race theory to explain the distributions of plant-herbivore interactions and plant-volatile associations observed in plant-herbivore communities. We received a comment by Bass and Kessler (Oct. 2020) questioning this theory and suggesting that a simpler neutral model can explain the observed distributions. This, with our response, went to peer review and was not published (Oct. 29, 2020). The authors have decided to publish their comment on EcoEvoRxiv (2) and so here, we are posting our reply. In sum, we present arguments to show that the comment from Bass and Kessler is based on an incorrect understanding of our study and furthermore suffers from circular reasoning, and that therefore their conclusions are not supported.



2021 ◽  
Vol 118 (12) ◽  
pp. e2023872118
Author(s):  
Ignasi Bartomeus ◽  
Serguei Saavedra ◽  
Rudolf P. Rohr ◽  
Oscar Godoy

Ecological theory predicts that species interactions embedded in multitrophic networks shape the opportunities for species to persist. However, the lack of experimental support of this prediction has limited our understanding of how species interactions occurring within and across trophic levels simultaneously regulate the maintenance of biodiversity. Here, we integrate a mathematical approach and detailed experiments in plant–pollinator communities to demonstrate the need to jointly account for species interactions within and across trophic levels when estimating the ability of species to persist. Within the plant trophic level, we show that the persistence probability of plant species increases when introducing the effects of plant–pollinator interactions. Across trophic levels, we show that the persistence probabilities of both plants and pollinators exhibit idiosyncratic changes when experimentally manipulating the multitrophic structure. Importantly, these idiosyncratic effects are not recovered by traditional simulations. Our work provides tractable experimental and theoretical platforms upon which it is possible to investigate the multitrophic factors affecting species persistence in ecological communities.



2019 ◽  
Vol 25 ◽  
Author(s):  
Heather Briggs ◽  
Carolyn A. Ayers ◽  
Paul R. Armsworth ◽  
Berry J. Brosi

Given ongoing pollinator declines, it is important to understand the dynamics of linked extinctions of plants driven by pollinator extinctions. Topological robustness models focused on this question suggest relatively high robustness of plant species to pollinator species extinctions. Still, existing robustness models typically assume that all interactions in plant-pollinator networks are positive, which is clearly not always the case. For example, many pollinators remove floral resources without transferring pollen, or even damage floral structures in the case of nectar robbing. Here we introduce antagonistic interactions into plant-pollinator networks and assess the resilience of plant communities to pollinator species losses. Incorporating antagonistic interactions leads to lower network robustness, i.e. an increased rate of plant species loss (as compared to networks with only mutualistic interactions) in empirical plant-pollinator networks. In conjunction with extinction order, the addition of increasingly antagonistic interactions was idiosyncratic in that it did not always magnify the effects of extinction order across the three networks. These results underscore the importance of considering the full spectrum of interaction outcomes when assessing robustness to coextinctions in plant-pollinator networks, as well as other ecological systems.



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