Citation: Yi X, Wang Z, Liu C, Liu G, 2015. Seed trait and rodent species determine seed dispersal and predation: evidences from semi-natural enclosures. iForest 8: 207-213 [online 2014-08-28] URL: http://www.sisef.it/iforest/contents/?id=ifor1185-008 Communicated by: Massimo FaccoliSeed trait and rodent species determine seed dispersal and predation: evidences from semi-natural enclosures Xianfeng Yi (1) , Zhenyu Wang (1) , Changqu Liu (2) , Guoqiang Liu (2) Seed traits affect seed dispersal by animals. However, the combined role of seeds and dispersers in determining seed dispersal is not well explored. We attempted to test how seed traits and predators determine seed dispersal and predation interaction in a rodent-mediated seed dispersal system. Semi-natural enclosure experiments were conducted to investigate seed dispersal and predation of five sympatric tree species with different seed traits, Juglans mandshurica, Quercus mongolica, Pinus koraiensis, Corylus mandshurica and C. heterophylla by three rodent species, Apodemus peninsulae, Tamias sibiricus and Clethrionomys rufocanus showing different body sizes, hoarding behaviors and activity rhythms. Our results demonstrated that seed species with thick coat were removed more slowly than thin-coated seeds in regardless of rodent species, reflecting a consistent negative effect of seed coat on seed dispersal. Seeds with thick coat were less likely to be eaten both in situ and after removal by small rodents. Seeds with high caloric value were more likely to be larder-hoarded, whereas seed traits showed no influence on scatter-hoarding. Rodent species with large body size tended to eat more seeds in situ, while small-sized rodents preferred to eat seeds after removal. Large-sized rodent species scatter-hoarded more seeds, however, small-sized rodents larder-hoarded more seeds. Seeds with thick coat showed high mutualism but low predation with rodents, while rodents with large size showed low mutualism but high predation with seeds. Our results indicate that both seeds and predators play important roles in determining seed dispersal and predation in the seed-rodent dispersal system. Keywords: Body Size, Caloric Value, Seed Coat, Seed Dispersal thin coat because thick coat usually increase the time for rodents to eat seeds ; (2) thick-coated seeds will be less likely eaten in situ but more likely eaten after removal according to the handling-time hypothesis; (3) more seeds with high caloric value will be hoarded by rodents according to the optimal forage theory (Pyke 1984); (4) large-sized rodent species will eat more seeds in situ, while rodents with small size tend to eat seeds after removal; (5) largesized rodents will larder-hoard more seeds than small-sized ones, while rodents with small size will scatter-hoard more seeds than large-sized rodents due to their lower ability to defend larders (MacDonald 1976, Preston & Jacobs 2001. Materials and methods Study siteThis study was conducted in the Dongfanghong Forestry Center (average elevation 750 m...

SummaryEven though beneficial plant-microbe interactions are commonly observed in nature, direct evidence for the evolution of bacterial mutualism in the rhizosphere remains elusive. Here we use experimental evolution to causally show that initially plant-antagonistic Pseudomonas protegens bacterium evolves into mutualists in the rhizosphere of Arabidopsis thaliana within six plant growth cycles (6 months). This evolutionary transition was accompanied with increased mutualist fitness via two mechanisms: i) improved competitiveness for root exudates and ii) enhanced capacity for activating the root-specific transcription factor gene MYB72, which triggers the production of plant-secreted scopoletin antimicrobial for which the mutualists evolved relatively higher tolerance to. Genetically, mutualism was predominantly associated with different mutations in the GacS/GacA two-component regulator system, which conferred high fitness benefits only in the presence of plants. Together, our results show that bacteria can rapidly evolve along the parasitism-mutualism continuum in the plant rhizosphere at an agriculturally relevant evolutionary timescale.