Abstract:Interspecific interactions are affected by community context and, as a consequence, show spatial variation in magnitude and sign. The selective forces imposed by interactions at the mutualism-antagonism interface are a consequence of the traits involved and their matching between species. If mutualistic and antagonistic communities are linked by gene flow, coevolution between a pair of interacting species is influenced by how selection varies in space. Here we investigate the effects of metacommunity arrangeme… Show more
“…;May 2016;Lemos-Costa et al 2017;Nelson and May 2020;Stevens et al 2021). analysesaster: https://cran.r-project.org/web/packages/aster/index.html aster2: https://cran.r-project.org/web/packages/aster2/index.html …”
The ecological and evolutionary consequences of microbiome treatments aimed to protect plants and animals against infectious disease are not well understood, even as such biological control measures become more common in agriculture and medicine. Notably, we lack information on the impacts of symbionts on pathogen fitness with which to project the consequences of competition for the evolution of virulence. To address this gap, we estimated fitness consequences for a common plant pathogen, Ustilago maydis, over differing virulence levels and when the host plant (Zea mays) is co-infected with a defensive symbiont (Fusarium verticillioides), and compared these fitness estimates to those obtained when the symbiont is absent. Here, virulence is measured as the reduction in the growth of the host caused by pathogen infection. Results of aster statistical models demonstrate that the defensive symbiont most negatively affects pathogen infection and that these effects propagate through subsequent stages of disease development to cause lower pathogen fitness across all virulence levels. Moreover, the virulence level at which pathogen fitness is maximal is higher in the presence of the defensive symbiont than in its absence. Thus, as expected from theory for multiple parasites, competition from the defensive symbiont may cause selection for increased pathogen virulence. More broadly, we consider that the evolutionary impacts of interactions between pathogens and microbial symbionts will depend critically on biological context and environment, and that interactions among diverse microbial symbionts in spatially heterogenous communities contributes to the maintenance of the highly diverse symbiotic functions observed in these communities.
“…;May 2016;Lemos-Costa et al 2017;Nelson and May 2020;Stevens et al 2021). analysesaster: https://cran.r-project.org/web/packages/aster/index.html aster2: https://cran.r-project.org/web/packages/aster2/index.html …”
The ecological and evolutionary consequences of microbiome treatments aimed to protect plants and animals against infectious disease are not well understood, even as such biological control measures become more common in agriculture and medicine. Notably, we lack information on the impacts of symbionts on pathogen fitness with which to project the consequences of competition for the evolution of virulence. To address this gap, we estimated fitness consequences for a common plant pathogen, Ustilago maydis, over differing virulence levels and when the host plant (Zea mays) is co-infected with a defensive symbiont (Fusarium verticillioides), and compared these fitness estimates to those obtained when the symbiont is absent. Here, virulence is measured as the reduction in the growth of the host caused by pathogen infection. Results of aster statistical models demonstrate that the defensive symbiont most negatively affects pathogen infection and that these effects propagate through subsequent stages of disease development to cause lower pathogen fitness across all virulence levels. Moreover, the virulence level at which pathogen fitness is maximal is higher in the presence of the defensive symbiont than in its absence. Thus, as expected from theory for multiple parasites, competition from the defensive symbiont may cause selection for increased pathogen virulence. More broadly, we consider that the evolutionary impacts of interactions between pathogens and microbial symbionts will depend critically on biological context and environment, and that interactions among diverse microbial symbionts in spatially heterogenous communities contributes to the maintenance of the highly diverse symbiotic functions observed in these communities.
“…By contrast, when two species-rich, local communities are linked by gene flow, mutualistic coevolution increases the convergence and matching of traits among all species of the two local communities [45]. While the effects of spatial processes on coevolution are starting to be unravelled [39,41,42,45,46], we still know little about how coevolution can affect distribution patterns in a heterogeneous environment or whether coevolution favours or hinders persistence across space under environmental changes. Figure 1Representation of coevolving mutualists in a metacommunity.…”
Section: Introductionmentioning
confidence: 99%
“…Spatial heterogeneity may impose different local evolutionary regimes, but colonization dynamics may alter the distribution of genotypes and phenotypes of populations across space, which feeds back and affects local evolutionary and coevolutionary dynamics [33][34][35][36][37][38] (figure 1). For instance, variation in mutualistic selection across space can create geographical mosaics of adaptation [39][40][41][42][43][44]. By contrast, when two species-rich, local communities are linked by gene flow, mutualistic coevolution increases the convergence and matching of traits among all species of the two local communities [45].…”
Linking local to regional ecological and evolutionary processes is key to understand the response of Earth's biodiversity to environmental changes. Here we integrate evolution and mutualistic coevolution in a model of metacommunity dynamics and use numerical simulations to understand how coevolution can shape species distribution and persistence in landscapes varying in space and time. Our simulations show that coevolution and species richness can synergistically shape distribution patterns by increasing colonization and reducing extinction of populations in metacommunities. Although conflicting selective pressures emerging from mutualisms may increase mismatches with the local environment and the rate of local extinctions, coevolution increases trait matching among mutualists at the landscape scale, counteracting local maladaptation and favouring colonization and range expansions. Our results show that by facilitating colonization, coevolution can also buffer the effects of environmental changes, preventing species extinctions and the collapse of metacommunities. Our findings reveal the mechanisms whereby coevolution can favour persistence under environmental changes and highlight that these positive effects are greater in more diverse systems that retain landscape connectivity.
“…Studying entire communities requires consideration of the reciprocal evolutionary changes species impose on each other both directly and indirectly (terHorst et al, 2018). While the interplay between spatial dynamics and coevolution has been explored (Fernandes et al, 2019; Gibert et al, 2013; Gordon et al, 1996; Lemos‐Costa et al, 2017; Medeiros et al, 2018; Thompson, 2005), the effects of habitat loss and fragmentation have not been explicitly considered. Therefore, the extent to which habitat destruction influences the eco‐(co)evolutionary feedback within communities remains unknown.…”
Habitat destruction is a growing threat to biodiversity and ecosystem services. The ecological consequences of habitat loss and fragmentation involve reductions in species abundance and even the extinction of species and their interactions. However, we do not yet understand how habitat loss alters the coevolutionary trajectories of the remaining species or how coevolution, in turn, affects their response to habitat loss. To investigate this, we develop a spatially explicit model which couples metacommunity and coevolutionary dynamics. We show that, by changing the size, composition and structure of local networks, habitat destruction increases the diversity of coevolutionary trajectories of mutualists across the landscape. Conversely, in antagonistic communities, some species increase while others reduce their spatial trait heterogeneity. Furthermore, we show that while coevolution dampens the negative effects of habitat destruction in mutualistic networks, its effects on the persistence of antagonistic communities tend to be smaller and less predictable.
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