The eco‐evolutionary dynamics of prior selfing rates promote coexistence without niche partitioning under conditions of reproductive interference

1. Pollinator-mediated reproductive interference can occur when two or more plant species share the same pollinators. Recent studies have suggested that prior autonomous selfing mitigates reproductive interference, potentially facilitating coexistence even in the absence of pollination niche partitioning (i.e. the pre-emptive selfing hypothesis). However, whether the evolution of prior selfing promotes coexistence, in the context of the eco-evolutionary dynamics of population size, selfing rates and inbreeding depression, remains poorly understood. 2. We constructed an individual-based model to examine the conditions under which the evolution of prior selfing promotes coexistence in the context of mutual reproductive interference. In the model, two plant species compete by way of mutual reproductive interference, and both have the potential to evolve the capacity for prior autonomous selfing. We expected that purging of deleterious mutations might result in evolutionary rescue, assuming that the strength of inbreeding depression declines as the population selfing rate increases; this would enable inferior competitors to maintain population density through the evolution of prior selfing. 3. Our simulation demonstrated that evolution of prior selfing may promote coexistence, whereas reproductive interference in the absence of such evolution results in competitive exclusion. We found that lower pollinator availability is likely to favour rapid evolutionary shifts to higher prior selfing rates, thereby neutralising the negative effects of reproductive interference in both species. When the strength of inbreeding depression decreased with an increase in the population-level selfing rate, moderate pollinator availability resulted in long-term coexistence in which relative abundance-dependent selection on the prior selfing rate served to intermittently maintain the population density of the inferior competitor. 4. Synthesis. We demonstrate that the evolution of prior selfing may increase population growth rates of inferior competitors and may consequently promote long-term coexistence via an evolutionary rescue. This constitutes a novel mechanism explaining the co-evolutionary coexistence of closely related plant species without niche partitioning, and is consistent with recent studies reporting that closely related species with mixed mating systems can co-occur sympatrically, even under conditions of mutual reproductive interference

HIV-1 competition experiments in humanized mice show that APOBEC3H imposes selective pressure and promotes virus adaptation

APOBEC3 (A3) family proteins are DNA cytosine deaminases recognized for contributing to HIV-1 restriction and mutation. Prior studies have demonstrated that A3D, A3F, and A3G enzymes elicit a robust anti-HIV-1 effect in cell cultures and in humanized mouse models. Human A3H is polymorphic and can be categorized into three phenotypes: stable, intermediate, and unstable. However, the anti-viral effect of endogenous A3H in vivo has yet to be examined. Here we utilize a hematopoietic stem cell-transplanted humanized mouse model and demonstrate that stable A3H robustly affects HIV-1 fitness in vivo. In contrast, the selection pressure mediated by intermediate A3H is relaxed. Intriguingly, viral genomic RNA sequencing reveled that HIV-1 frequently adapts to better counteract stable A3H during replication in humanized mice. Molecular phylogenetic analyses and mathematical modeling suggest that stable A3H may be a critical factor in human-to-human viral transmission. Taken together, this study provides evidence that stable variants of A3H impose selective pressure on HIV-1

Recurrent speciation rates on islands decline with species number

In an archipelagic system, species diversity is maintained and determined by the balance among speciation, extinction and migration. As the number of species increases, the average population size of each species decreases, and the extinction likelihood of any given species grows. By contrast, the role of reduced population size in geographic speciation has received comparatively less research attention. Here, to study the rate of recurrent speciation, we adopted a simple multi-species two-island model and considered symmetric interspecific competition on each island. As the number of species increases on an island, the competition intensifies, and the size of the resident population decreases. By contrast, the number of migrants is likely to exhibit a weaker than proportional relationship with the size of the source population due to rare oceanic dispersal. If this is the case, as the number of species on the recipient island increases, the impact of migration strengthens and decelerates the occurrence of further speciation events. According to our analyses, the number of species can be stabilized at a finite level, even in the absence of extinction

Species-specific model to predict amphibian metamorphosis

Abstract Exploring the timing of life-history transitions has been a pivotal focus in the field of evolutionary ecology. Studies on amphibian metamorphosis are well suited to investigate this aspect. We propose a species-specific model to predict the optimal metamorphosis point for frog individuals with different larval growth trajectories. Because overall fitness will be determined throughout both aquatic and terrestrial stages, we included growth and survival rates of aquatic and terrestrial stages in the fitness equation. Then we conducted a rearing experiment on a brown frog, Rana ornativentris, as an example to obtain the size at metamorphosis, larval period, and larval growth trajectory. Based on these results, we determined the model's parameters to fit the actual metamorphosis patterns. Because the parameters are supposed to be evolutionarily maintained, our data-driven approach enabled obtaining fundamental ecological information (evolutionally-based life-history parameters) of the target species. Comparing the parameters among species will allow us to understand the mechanisms in determining life-history transition more deeply

TableS3_statistical.results.xlsx from Evolution of competitive traits changes species diversity in a natural field

Studying the interaction between evolutionary and ecological processes (i.e. eco-evolutionary dynamics) has great potential to improve our understanding of biological processes such as species interactions, community assembly and ecosystem functions. However, most experimental studies have been conducted under controlled laboratory or mesocosm conditions, and the importance of these interactions in natural field communities has not been evaluated. In this study, we focused on the contemporary divergence of a competitive trait (the height–width ratio) of an annual grass Eleusine indica between urban and farmland populations and investigated how trait evolution affects ecological processes by transplanting E. indica individuals from lineages with different trait values into semi-natural grassland. The competitive trait of the transplanted individuals not only affected their own growth and fitness, but also affected the vegetative growth of the competing species and the species diversity. These results indicate that the evolution of competitive traits, even in a single species, can influence the community species diversity through changes in interspecific interactions. Eco-evolutionary interactions therefore play a crucial role in natural field environments. Our results suggest that understanding intraspecific variation in competitive traits driven by rapid evolution is essential for understanding interspecific competitive interactions, community assembly and species diversity

Fukano_ProB_FigureS1-2.docx from Evolution of competitive traits changes species diversity in a natural field

Studying the interaction between evolutionary and ecological processes (i.e. eco-evolutionary dynamics) has great potential to improve our understanding of biological processes such as species interactions, community assembly and ecosystem functions. However, most experimental studies have been conducted under controlled laboratory or mesocosm conditions, and the importance of these interactions in natural field communities has not been evaluated. In this study, we focused on the contemporary divergence of a competitive trait (the height–width ratio) of an annual grass Eleusine indica between urban and farmland populations and investigated how trait evolution affects ecological processes by transplanting E. indica individuals from lineages with different trait values into semi-natural grassland. The competitive trait of the transplanted individuals not only affected their own growth and fitness, but also affected the vegetative growth of the competing species and the species diversity. These results indicate that the evolution of competitive traits, even in a single species, can influence the community species diversity through changes in interspecific interactions. Eco-evolutionary interactions therefore play a crucial role in natural field environments. Our results suggest that understanding intraspecific variation in competitive traits driven by rapid evolution is essential for understanding interspecific competitive interactions, community assembly and species diversity

TableS1_species.list.xlsx from Evolution of competitive traits changes species diversity in a natural field

Studying the interaction between evolutionary and ecological processes (i.e. eco-evolutionary dynamics) has great potential to improve our understanding of biological processes such as species interactions, community assembly and ecosystem functions. However, most experimental studies have been conducted under controlled laboratory or mesocosm conditions, and the importance of these interactions in natural field communities has not been evaluated. In this study, we focused on the contemporary divergence of a competitive trait (the height–width ratio) of an annual grass Eleusine indica between urban and farmland populations and investigated how trait evolution affects ecological processes by transplanting E. indica individuals from lineages with different trait values into semi-natural grassland. The competitive trait of the transplanted individuals not only affected their own growth and fitness, but also affected the vegetative growth of the competing species and the species diversity. These results indicate that the evolution of competitive traits, even in a single species, can influence the community species diversity through changes in interspecific interactions. Eco-evolutionary interactions therefore play a crucial role in natural field environments. Our results suggest that understanding intraspecific variation in competitive traits driven by rapid evolution is essential for understanding interspecific competitive interactions, community assembly and species diversity