We construct a dynamic system model of a web of NA?animal species interacting with NP plant species using a system of coupled differential equations. The model has a parameter which represents the effect of animal on ...We construct a dynamic system model of a web of NA?animal species interacting with NP plant species using a system of coupled differential equations. The model has a parameter which represents the effect of animal on plant species that can be positive (mutualistic interaction) or negative (antagonistic interaction). We work a Multispecies Mean Field Model MMFM in which the full set of NA and NP variables are reduced to a couple of an average animal and plant species. We study the conditions for existence of the MMFM and relate the result to the difference between animal and plant species in the network. We compare our results with empirical data from pollinators (mutualistic) and herbivorous insect (antagonistic) networks. We conclude by combining analytical and empirical work that antagonistic networks present fewer animal species in relation to plant species than mutualistic ones.展开更多
The richness of spider species on the foliage of Mexican ant-acacias in Los Tuxtlas (Veracruz), and Santiago Pinotepa Nacional (Oaxaca) was documented. A total of 11 species, grouped into five families were found;in L...The richness of spider species on the foliage of Mexican ant-acacias in Los Tuxtlas (Veracruz), and Santiago Pinotepa Nacional (Oaxaca) was documented. A total of 11 species, grouped into five families were found;in Los Tuxtlas five species representing two families were identified, whereas in Santiago Pinotepa Nacional, the number of taxa was eight, belonging to five families. The richness of spiders in Santiago Pinotepa Nacional was higher than that found in Los Tuxtlas. In both locations <em>Nephila clavipes</em> Linnaeus and <em>Eustala illicita</em> O. Pickard-Cambridge, both from Araneidae, were found;these species had been previously reported as common inhabitants of Central American ant-acacias. The presence of <em>E. illicita</em> in Mexican myrmecophytic acacias was confirmed. A total of 10 species grouped into five families are reported for the first time inhabiting Mexican ant-acacias, increasing the richness of spider interactions documented in Mexico. This study showed that the occurrence of spiders in the <em>Vachellia-Pseudomyrmex</em> mutualism system has been overlooked and is likely more common than what has been reported until now. This opens an opportunity for the study of the evolution of spider-ant-plant interactions.展开更多
Scatter-hoarding rodents play a crucial role in seed survival and seed dispersal.As one of the most important seed traits,seed size and its effect on rodent–seed interaction attract lots of attention.Current studies ...Scatter-hoarding rodents play a crucial role in seed survival and seed dispersal.As one of the most important seed traits,seed size and its effect on rodent–seed interaction attract lots of attention.Current studies usually target one or a few species and show inconsistent patterns;however,few experiments include a large number of species although many plant species usually coexist in natural forest and overlap in fruiting time.Here,we tracked the dispersal and predation of 26100 seeds belonging to 41 tree species in a subtropical forest for 2 years.Most species showed no relationships between seed size and rodent foraging preference,while the remaining species displayed diverse of patterns:monotonic decrease and increase trends,and hump-shaped and U-shaped patterns,indicating that a one-off study with a few species might give misleading information.However,the seed size effect across species was consistent in both years,indicating that including a large number of species that hold a sufficient range of seed size may avoid the aforementioned bias.Interestingly,seed size effect differed among rodent foraging processes:a negative effect on seed harvest,a hump-shaped effect on seed removal and removal distance,while a positive effect on overwinter survival of cached seeds,indicating that rodents may make trade-offs between large and small seeds both among foraging processes and within a single process,thus lead to a parabolic relationship between seed size and seed dispersal success,that is medium-sized seeds were more likely to be removed and cached,and transported with a further distance.展开更多
Global warming is predicted to affect plant-herbivore interactions. However, little is known about the effects of temperature on marine plant secondary chemistry and how these effects may impact plant-herbivore intera...Global warming is predicted to affect plant-herbivore interactions. However, little is known about the effects of temperature on marine plant secondary chemistry and how these effects may impact plant-herbivore interactions. As marine macroalgae can become physiologically stressed due to warm water temperatures and nutrient-poor conditions during summer, we conducted a culture experiment to test the combined effects of temperature (10°C, 20°C, 30°C) and nutrient availability (seawater enriched with 25% PESI medium and non-enriched seawater) on relative growth rate (RGR) and concentration of phlorotannins (i.e., defensive compounds) in the upper and lower parts of shoots of the brown alga Sargassum patens. RGR was affected by temperature but not by nutrient availability. Phlorotannnin concentration was affected by nutrient availability but not by temperature, although there was a significant interaction between temperature and part of the shoots. Correlations between RGR and phlorotannin concentration were significant for the upper part of the shoots but not for the lower part. These correlations were slightly positive in the nutrient-enriched medium but negative in the non-enriched medium. These results suggest that temperature affects phlorotannin concentration of S. patens indirectly via changes in the growth rate and that its effect depends on the part of the shoot and nutrient availability.展开更多
After maturation, Korean pine (Pinus koraiensis Siebold & Zucc.) seeds often cannot disperse to reach a suitable germination site. It is therefore difficult to naturally regenerate by itself and relies on animal d...After maturation, Korean pine (Pinus koraiensis Siebold & Zucc.) seeds often cannot disperse to reach a suitable germination site. It is therefore difficult to naturally regenerate by itself and relies on animal dispersal. Squirrels hoard pine seeds as winter food and Korean pine seeds stored for overwintering might become the source of regeneration of the species. From field observations, the pine seeds are the food preference for squirrels during autumn in the Lesser Khingan Mountains in Northeast China. Such preference by squirrels has been attributed to high seed energy content and the ease of seed storage. However, it may also be expected from nutritional aspects that a coevolutionary relationship between squirrels and Korean pine species could be partially explained by the effect of active seed components and their physiological regulatory effects on squirrels. To test this hypothesis, control experiments were carried out to examine the modulatory effects of Korean pine nut oil (PNO) on intestinal microbiota, inflammatory profile and oxidative stress in mice. The results showed that, compared with mice fed a high-fat diet, PNO significantly improved the physical and the healthy state of mice. Histological analysis of the liver and epididymal fat tissue showed that PNO alleviated liver and adipocyte lesions, and inflammation caused by high-fat diets. PNO also significantly decreased atherosclerotic index and ameliorate serum lipid accumulation to prevent cardiovascular disease, which effect the positive control SG group. Moreover, PNO elevated superoxide dismutase and glutathione peroxidase enzyme activities and reduced malondialdehyde levels in the serum. 16S rRNA sequencing showed that PNO restored intestinal microbiota composition, significantly increasing the relative abundance of Lactobacillus and Akkermansia bacteria. These results suggest that Korean pine seeds not only provide adequate fat, protein and energy for squirrels, but also promote physical health and improve body immunity.展开更多
文摘We construct a dynamic system model of a web of NA?animal species interacting with NP plant species using a system of coupled differential equations. The model has a parameter which represents the effect of animal on plant species that can be positive (mutualistic interaction) or negative (antagonistic interaction). We work a Multispecies Mean Field Model MMFM in which the full set of NA and NP variables are reduced to a couple of an average animal and plant species. We study the conditions for existence of the MMFM and relate the result to the difference between animal and plant species in the network. We compare our results with empirical data from pollinators (mutualistic) and herbivorous insect (antagonistic) networks. We conclude by combining analytical and empirical work that antagonistic networks present fewer animal species in relation to plant species than mutualistic ones.
文摘The richness of spider species on the foliage of Mexican ant-acacias in Los Tuxtlas (Veracruz), and Santiago Pinotepa Nacional (Oaxaca) was documented. A total of 11 species, grouped into five families were found;in Los Tuxtlas five species representing two families were identified, whereas in Santiago Pinotepa Nacional, the number of taxa was eight, belonging to five families. The richness of spiders in Santiago Pinotepa Nacional was higher than that found in Los Tuxtlas. In both locations <em>Nephila clavipes</em> Linnaeus and <em>Eustala illicita</em> O. Pickard-Cambridge, both from Araneidae, were found;these species had been previously reported as common inhabitants of Central American ant-acacias. The presence of <em>E. illicita</em> in Mexican myrmecophytic acacias was confirmed. A total of 10 species grouped into five families are reported for the first time inhabiting Mexican ant-acacias, increasing the richness of spider interactions documented in Mexico. This study showed that the occurrence of spiders in the <em>Vachellia-Pseudomyrmex</em> mutualism system has been overlooked and is likely more common than what has been reported until now. This opens an opportunity for the study of the evolution of spider-ant-plant interactions.
基金funded by the National Natural Science Foundation of China(31971444 and 32171533).
文摘Scatter-hoarding rodents play a crucial role in seed survival and seed dispersal.As one of the most important seed traits,seed size and its effect on rodent–seed interaction attract lots of attention.Current studies usually target one or a few species and show inconsistent patterns;however,few experiments include a large number of species although many plant species usually coexist in natural forest and overlap in fruiting time.Here,we tracked the dispersal and predation of 26100 seeds belonging to 41 tree species in a subtropical forest for 2 years.Most species showed no relationships between seed size and rodent foraging preference,while the remaining species displayed diverse of patterns:monotonic decrease and increase trends,and hump-shaped and U-shaped patterns,indicating that a one-off study with a few species might give misleading information.However,the seed size effect across species was consistent in both years,indicating that including a large number of species that hold a sufficient range of seed size may avoid the aforementioned bias.Interestingly,seed size effect differed among rodent foraging processes:a negative effect on seed harvest,a hump-shaped effect on seed removal and removal distance,while a positive effect on overwinter survival of cached seeds,indicating that rodents may make trade-offs between large and small seeds both among foraging processes and within a single process,thus lead to a parabolic relationship between seed size and seed dispersal success,that is medium-sized seeds were more likely to be removed and cached,and transported with a further distance.
文摘Global warming is predicted to affect plant-herbivore interactions. However, little is known about the effects of temperature on marine plant secondary chemistry and how these effects may impact plant-herbivore interactions. As marine macroalgae can become physiologically stressed due to warm water temperatures and nutrient-poor conditions during summer, we conducted a culture experiment to test the combined effects of temperature (10°C, 20°C, 30°C) and nutrient availability (seawater enriched with 25% PESI medium and non-enriched seawater) on relative growth rate (RGR) and concentration of phlorotannins (i.e., defensive compounds) in the upper and lower parts of shoots of the brown alga Sargassum patens. RGR was affected by temperature but not by nutrient availability. Phlorotannnin concentration was affected by nutrient availability but not by temperature, although there was a significant interaction between temperature and part of the shoots. Correlations between RGR and phlorotannin concentration were significant for the upper part of the shoots but not for the lower part. These correlations were slightly positive in the nutrient-enriched medium but negative in the non-enriched medium. These results suggest that temperature affects phlorotannin concentration of S. patens indirectly via changes in the growth rate and that its effect depends on the part of the shoot and nutrient availability.
基金This work was supported by the Heilongjiang Province Hundred Million Engineering Science and Technology Major Project(2020ZX07B01).
文摘After maturation, Korean pine (Pinus koraiensis Siebold & Zucc.) seeds often cannot disperse to reach a suitable germination site. It is therefore difficult to naturally regenerate by itself and relies on animal dispersal. Squirrels hoard pine seeds as winter food and Korean pine seeds stored for overwintering might become the source of regeneration of the species. From field observations, the pine seeds are the food preference for squirrels during autumn in the Lesser Khingan Mountains in Northeast China. Such preference by squirrels has been attributed to high seed energy content and the ease of seed storage. However, it may also be expected from nutritional aspects that a coevolutionary relationship between squirrels and Korean pine species could be partially explained by the effect of active seed components and their physiological regulatory effects on squirrels. To test this hypothesis, control experiments were carried out to examine the modulatory effects of Korean pine nut oil (PNO) on intestinal microbiota, inflammatory profile and oxidative stress in mice. The results showed that, compared with mice fed a high-fat diet, PNO significantly improved the physical and the healthy state of mice. Histological analysis of the liver and epididymal fat tissue showed that PNO alleviated liver and adipocyte lesions, and inflammation caused by high-fat diets. PNO also significantly decreased atherosclerotic index and ameliorate serum lipid accumulation to prevent cardiovascular disease, which effect the positive control SG group. Moreover, PNO elevated superoxide dismutase and glutathione peroxidase enzyme activities and reduced malondialdehyde levels in the serum. 16S rRNA sequencing showed that PNO restored intestinal microbiota composition, significantly increasing the relative abundance of Lactobacillus and Akkermansia bacteria. These results suggest that Korean pine seeds not only provide adequate fat, protein and energy for squirrels, but also promote physical health and improve body immunity.
