Biology subjects

Yamawo, A.

Publications and source records attributed to Yamawo, A..

6 recordsLinked to original sources

bioRxiv2026

Coexistence of annual plants under competition and reproductive interference

In natural ecosystems, community dynamics are driven by diverse interactions operating through both ecological and reproductive processes. Although theory predicts that these processes jointly generate complex and contingent dynamics through the interplay of stabilizing (negative frequency dependence arising from niche differences) and destabilizing effects (positive frequency dependence caused by reproductive interference), empirical tests of this prediction remain scarce. Here, we combined experimental and theoretical approaches to investigate the dynamics of two congeneric annual plant species (Commelina) experiencing both ecological competition and reproductive interference. Our empirically parameterized model revealed a large niche difference and mutual reproductive interference. However, the reproductive interference was not strong enough to generate pronounced contingency of community dynamics on initial conditions. Instead, coexistence was the most likely outcome regardless of initial species composition. Parameter exploration indicated that the weak contingency arose because reproductive assurance strategies of Commelina species buffered the minority disadvantage caused by reproductive interference. These findings provide empirical evidence that reproductive interference does not necessarily destabilize coexistence and that it may be outweighed by ecological niche and fitness differences. Our study highlights the importance of integrating ecological and reproductive processes towards better prediction of community dynamics.

ecology↗

bioRxiv2026

Genotype-dependent reductions of competition are associated with yield maintenance in a modern common wheat Triticum aestivum L. cultivar

Modern crop breeding has increased yield under monoculture stands, but the mechanisms underlying this improvement remain incompletely understood. We tested whether genotype-dependent reduction of competition, whereby plants adjust competitive responses according to neighbor genetic identity, contributes to yield maintenance in modern common wheat cultivars. We conducted a root-exudate application experiment and two competition experiments using three common wheat (Triticum aestivum L.) landraces and one modern cultivar, Norin 61. Norin 61 exhibited little change in shoot-to-root allocation in response to root exudates from the same cultivar compared with distilled water, whereas it increased shoot-to-root allocation exposed to root exudate from different cultivars. Moreover, shoot-to-root allocation increased with decreasing genetic relatedness between neighboring cultivars in common wheat plants. In competition experiments, greater shoot-to-root allocation was associated with stronger suppression of competitors. Norin 61 maintained grain biomass under the same-cultivar competition compared to solitary conditions but exhibited substantial yield reductions when competing with different cultivars, whereas these patterns were weaker or absent in landraces. These results suggest that genotype-dependent reduction of competition may contribute to yield maintenance in modern wheat cultivars and provide a new perspective on how crop breeding has shaped plant-plant interactions in monoculture stands.

ecology↗

bioRxiv2023

Plant-mycorrhizal associations may explain the latitudinal gradient of plant community assembly

Biogeographical variation in community assembly patterns forms the basis of large-scale biodiversity gradients. Previous studies on community assembly have suggested the dominant role of environmental filtering at higher latitudes. However, recent evidence indicates that plant community distributions at higher latitudes exhibit more spatial clustering, suggesting the importance of spatial assembly processes. In this study, we propose a hypothesis that resolves this paradox by incorporating biogeographic variations in dominant mycorrhizal types: the increasing prevalence of ectomycorrhizal (EcM) trees with latitude contributes to the spatially clustered distribution of plants, as EcM trees tend to exhibit positive plant-soil feedback. We analyzed a large-scale standardized dataset of Japanese forests covering a latitudinal gradient of >10{degrees} and found that (i) the proportion of EcM trees was higher at higher latitudes, and (ii) EcM tree-rich communities exhibited more spatially clustered distributions. Consequently, (iii) the tree species composition at higher latitudes was better explained by spatial variables. Moreover, consistent with predictions derived from the plant-soil feedback theory, these findings were particularly evident in the understory rather than the canopy communities. This study demonstrates that plant-soil feedback influences plant community distributions at metacommunity scales, thereby giving rise to a paradox within the latitudinal gradient of plant community assembly.

ecology↗

bioRxiv2022

Evolutionary relations between mycorrhizal symbiosis and plant-plant communication in trees

Ecological factors that drive the evolution of plant-plant communication via volatile organic compounds (VOCs) have not been elucidated. Here, we examined the relationship between type of mycorrhizal symbiosis (arbuscular mycorrhiza, AM; ectomycorrhizal mycorrhiza, ECM) and plant-plant communication within tree species. We hypothesized that ECM promotes plant-plant communication among conspecific individuals in trees, because it promotes their cooccurrence through positive plant-soil feedback. We tested communication using saplings of nine tree species with either AM or ECM, either exposed for 10 days to volatiles from an injured conspecific or not exposed. We evaluated the number of insect-damaged leaves and the area of leaf damage after 1 and 2 months in the field. Most exposed ECM-associated trees had less leaf damage than controls. However, AM-associated trees did not differ in leaf damage between treatments. We combined our results with those of previous studies and analysed the evolutionary relation between mycorrhizal type and the presence or absence of plant-plant communication within tree species. ECM symbiosis is associated with the evolution of plant-plant communication within species. These results suggest that the evolution of types of mycorrhizal symbiosis associates with the evolution of plant-plant communications within tree species.

ecology↗

bioRxiv2021

Intraspecific interaction of host plant influences local distribution of specialist herbivores through metabolic alterations in leaves

O_LIRecent studies suggest that changes in leaf traits due to interactions between plants affect the resource utilisation and distribution of herbivores. However, this has not yet been confirmed experimentally. Here, we investigated the effects of phenotypic plasticity in leaf traits of Rumex obtusifolius (host plant) in response to the intra- and interspecific interaction on distribution of two leaf beetles, Gastrophysa atrocyanea (specialist herbivore) and Galerucella grisescens (generalist herbivore). C_LIO_LIWe investigated the local population density of R. obtusifolius plants and the presence of leaf beetles on the plants at five study sites. Leaf chemicals (condensed tannins and total phenolics) were compared between aggregated and solitary R. obtusifolius plants. To clarify the effects of the interaction environment of R. obtusifolius plants on their leaf traits and resource utilisation by leaf beetles, we conducted cultivation and preference experiments. Leaf chemicals (chlorophylls, organic acids, primary metabolites, condensed tannins and total phenolics) and preferences of adult leaf beetles were compared between intraspecific, interspecific plant interaction, or no-interaction treatments. Finally, we evaluated the effects of interaction between R. obtusifolius on leaf beetle distribution in mesocosm experiments. C_LIO_LIIn the field, the presence of the specialist leaf beetle, G. atrocyanea, was positively correlated with the local population density (rosette overlap ratio) of R. obtusifolius plants; however, no correlation was observed in the case of the generalist leaf beetle, G. grisescens. In the cultivation experiment, plants in the intraspecific interaction treatment increased their leaf contents of condensed tannins and total phenolics, and G. atrocyanea consumed more of these leaves than leaves in other treatments. Similar results were observed in the field. In the mesocosm experiment, larger numbers of G. atrocyanea were distributed on R. obtusifolius plants exposed to below-ground intraspecific interaction than on plants not exposed to intraspecific interaction. C_LIO_LIOur results provide experimental evidence that leaf-trait changes in response to intraspecific interaction between host plants influence specialist herbivore distribution. This highlights the need to integrate plant-plant interactions into our understanding of plant-animal interactions. C_LI

ecology↗

bioRxiv2020

Joint evolution of mycorrhizal type, pollination, and seed dispersal mode in trees

Although tree diversity is fundamental to terrestrial ecosystems, the processes that generate it remain uncertain. Mycorrhizal type, pollination mode, and seed dispersal mode may be key drivers of tree diversity. We predicted that mycorrhizal symbiosis drove evolution of pollination and seed dispersal modes because arbuscular mycorrhizal (AM) associations would favour long-range seed or pollen dispersal owing to their negative plant-soil-feedback effects on conspecific individuals, and ectomycorrhizal (EcM) associations would favour short-range dispersal owing to their positive effects. We analysed evolutionary relationships among mycorrhizal type, seed dispersal mode, and pollination mode in 704 tree species and conducted a meta-analysis of the dispersal distances of the various seed dispersal and pollination modes. We found evidence of joint evolution of all three features. Most AM-associated trees had endozoochorous seed dispersal and biotic pollination and these dispersal modes had long dispersal distances, whereas most EcM-associated trees had anemochorous seed dispersal and wind pollination and these dispersal modes had relatively shorter dispersal distances. Overall, evolution of mycorrhizal type, seed dispersal mode, and pollination mode were linked, strongly suggesting that mycorrhizal symbiosis drives the evolution of seed and pollination modes and contributes to tree diversification.

evolutionary biology↗