Labor division is a phenomenon observed across various biological contexts, including examples such as the differentiation between germ/somatic cells in multicellular organisms and the division between reproductive/worker individuals within social animal groups. In such cases, certain members contribute to tasks that enhance the viability of the entire group, even if this requires a reduction in their individual reproductive efforts. Given that group members have the potential to adopt varying contribution levels, a comprehensive analysis of the evolution becomes intricate due to the problem\'s high dimensionality. In this paper, I introduce a novel method for analyzing the evolution of the distribution of contribution levels to group viability, with a particular formulation centered on the success of clonal strains. The analysis demonstrates that the curvature of the fecundity function in relation to contributions to the group plays a pivotal role in determining the occurrence of labor division between reproductive and non-reproductive tasks, aligning in part with results from prior research. Furthermore, I extend this analysis to encompass contributions to multiple categories of tasks for group viability. My findings indicate that investments in non-reproductive tasks are selected based on the average contributions for each task, with individual variation playing a less significant role as long as average values remain consistent. Additionally, I explore the impact of group size and relatedness within the group on labor division. The results highlight that increases in group size and relatedness have a positive influence on the evolution of cooperation, although their effects are not directly tied to labor division itself.

Aim: Off-reserve conservation is a major contributor to China biodiversity conservation efforts, biodiversity conservation being achieved within afforestation and low-intensity agriculture in fragmented landscapes. Functional trait is more strongly related to ecological processes than taxonomic diversity and reflects ecosystem functioning and species responses to environmental changes. In this study, we selected five habitats that differ in degree of disturbance to explore the effects of land use on ant community compositions, traits distributions and functional diversity change. We assessed how habitat disturbance affects the ant community compositions and traits distributions and asked if ant functional diversity respond to disturbance at the local scale? Location: Lüchun County, Yunnan Province, southwest China. Methods: Pitfall traps were used to survey ant communities. Additionally, we measured four ant morphological traits (eyes diameter, distance between eyes, femur length of the hind-leg and Weber\'s length) to assess the functional traits distributions and functional diversity. Shade plot of ant relative abundance was used to explore species distribution amongst different habitats. Kernel density plot was used to explore ant traits distribution patterns amongst different habitats. Non-metric multi-dimensional scaling ordination, based on ant Weber\'s length, was used to explore the ant traits compositions amongst different habitats. The fourth corner model was used to evaluate the association between ant traits and environmental variables. The FRic, RaoQ and FEve indices were selected as three complementary measures of the multivariate functional traits space and functional redundancy of different habitats. Results: We collected 14258 ants, representing 89 species, 40 genera and seven subfamilies. Aphaenogasterschurri and Tetramoriumciliatum were the common species of secondary forest; P.sagei, P.pieli, Cardiocondylawroughtonii, Recurvidrisnuwa, Tapinnomamelanocephalum, Monomoriumpharaonis and M.orientale were the common species in plantations; and Iridomyrmexanceps and Cardiocondylanuda were the common species in managed farms. Ants had medium eye diameters, narrow distances between eyes, medium leg lengths and smaller body sizes in greatly-disturbed habitats; and ants had an increasing eye diameter and narrowing of the space between eyes, while the leg length and Weber\'s length became shorter in moderately-disturbed habitats. Ant trait composition, based on Weber\'s length, showed significantly differences amongst five habitats. The fourth corner analysis indicated that ant species traits were significantly correlated with environmental variables. The functional diversity of secondary forest, lac plantation and lac plantation-corn agroforest were higher than those in dryland farm and rice paddy. Functional diversities were significantly negatively correlated with bare ground cover and significantly positively correlated with leaf-litter cover, leaf-litter thickness and plant cover. Main conclusion: Our results indicated that ant traits distribution patterns were affected by land-use changes, followed by anthropogenic disturbance pressures at the local scale. Ant traits compositions in greatly-disturbed habitats also differed from the habitats with less disturbance. It is unfavourable for the survival of the large body-size ants in more open habitats with more anthropogenic disturbance. Compared with secondary forest, dryland farm and rice paddies were less resistant and more vulnerable and lac plantations had approximately functional diversity of ant communities, suggesting that lac plantations might be resistant as secondary forest to species loss.

Changes in the amount and timing of precipitation may affect plant species coexistence. However, little is known about how these changes in precipitation structure plant communities. Here, we conducted a 6-year field precipitation manipulation experiment in the semi-arid steppe of Inner Mongolia, China, to assess the importance of species extinction and colonization in community assembly by incorporating information on phylogenetic and functional relatedness. Our results demonstrated that the decline in plant species richness under decreasing precipitation in the late and entire growing season could be attributed to a decrease in species colonization and an increase in species loss, respectively. The increase in species richness under increasing precipitation in the late growing season was mainly caused by increases in colonizing species. The loss of species that were more closely related to other residents under decreasing precipitation in the late growing season did not alter patterns of phylogenetic overdispersion, and the colonization of species that were more distantly related to residents under increasing precipitation in the late growing season shifted functional relatedness from clustering to randomness. Increasing precipitation may weaken the strength of environmental filtering induced by water stress in this semi-arid steppe and thus increase the probability of successful colonization of functionally dissimilar species relative to residents. Our study suggests that incorporating information on the functional and phylogenetic relatedness of locally lost resident species and the colonization of new species into analyses of community assembly processes can provide new insights into the general responses of plant communities to global change.

Chlorophyll is the molecular basis for the function of photosystems and is also a promising tool for ecological prediction. However, the large-scale patterns of chlorophyll variation in grasslands remain poorly understood. We performed consistent measurements of chlorophyll a, b, a+b, and the a:b ratio (chlorophyll a/b) for 421 species across northern hemisphere grassland transects, recorded their distributions, variations, and influencing factors, and examined their relationships with leaf nitrogen. The results showed that the distributional ranges were 0.52-28.33 (mean 5.49) mg·g-1 dry weight, 0.15-12.11 (mean 1.83) mg·g-1 dry weight, 0.67-39.29 (mean 7.32) mg·g-1 dry weight, and 1.28-7.84 (mean 3.02) for chlorophyll a, b, a+b, and a/b, respectively. The chlorophyll averages differed among regions (higher in the Loess Plateau and the Mongolian Plateau than in the Tibetan Plateau), grassland types (desert grasslands > meadow > typical grasslands), life forms, life spans, and taxonomies. In the entire northern hemisphere grassland, chlorophyll concentrations and chlorophyll a/b were negatively correlated to photosynthetically active radiation and the soil N:P ratio, and positively correlated to the mean annual temperatures. These results implied that chlorophyll in grasslands was shaped by the layered structure of grasses, distinct plateau environments, and phylogeny. The allocation patterns of leaf nitrogen to chlorophyll differed among regions and grassland types, showing that caution is required if simply relating single leaf N or chlorophyll to productivity separately. These findings enhance our understanding of chlorophyll in natural grasslands on a large scale, as well as providing information for ecological predictive models.

Biological trait analysis (BTA) has been proved to be a powerful tool to evaluate marine water quality. The species trait distributions of biofilm-dwelling protozoa were studied in a coastal region of the Yellow Sea, northern China, during a four-season cycle. The BTA demonstrated that: (1) the protozoa showed a significant seasonal variability in biological trait pattern during the colonization process across four seasons; (2) the colonization dynamics in species trait distribution followed different temporal models; (3) the functional dynamics in spring and summer were significantly different from those in autumn and winter (P < 0.05); and (4) functional diversity showed lower values in spring and summer than in autumn and winter. These findings suggest that BTA is subject to a high seasonal variability during colonization surveys when protozoa are used as bioindicators of marine water quality.

Environmental filters affect community assembly through the functional traits of species. However, the process of community assembly remains unclear because of the complex interactions among the many biotic and abiotic factors. This study aimed to examine the community assembly process of vascular plants along gradients of elevation (45‒2500 m a.s.l.) and soil nitrogen availability. This study examined the trait distribution patterns of four functional traits (plant height, leaf area, specific leaf area and leaf nitrogen concentration) of vascular plants (trees, herbs and ferns) in central Japan, using null model testing. The number of species decreased and increased at high elevations for tree species and herb and fern species, respectively. The numbers of both tree species and herb and fern species were positively correlated with soil nitrogen availability. Community-weighted means (CWMs) of the four traits decreased with elevation. CWMs and ranges of the three leaf traits were positively correlated with soil nitrogen availability. The community-weighted variance of plant height was higher at higher elevations, indicating that niche differentiation of vertical stratum in habitats with a low canopy was important for community assembly. This study suggests that severe climatic conditions reduce the number of tree species and the canopy height at high elevations, leading to increases in the number of herb and fern species due to increased light intensity at the forest floor. The elevational change of leaf traits also indicates the change of adaptive leaf traits. It further suggests that lower nitrogen availability decreases the number of tree, herb and fern species by excluding those species with leaf traits unsuited to lower nitrogen availability. Therefore, community structure is most likely regulated by both elevation and soil nitrogen availability.

1. The environmental filtering hypothesis predicts that the abiotic environment selects species with similar trait values within communities. Testing this hypothesis along multiple - and interacting - gradients of climate and soil variables constitutes a great opportunity to better understand and predict the responses of plant communities to ongoing environmental changes. 2. Based on two key plant traits, maximum plant height and specific leaf area (SLA), we assessed the filtering effects of climate (mean annual temperature and precipitation, precipitation seasonality), soil characteristics (soil pH, sand content and total phosphorus) and all potential interactions on the functional structure and diversity of 124 dryland communities spread over the globe. The functional structure and diversity of dryland communities were quantified using the mean, variance, skewness and kurtosis of plant trait distributions. 3. The models accurately explained the observed variations in functional trait diversity across the 124 communities studied. All models included interactions among factors, i.e. climate - climate (9% of explanatory power), climate - soil (24% of explanatory power) and soil - soil interactions (5% of explanatory power). Precipitation seasonality was the main driver of maximum plant height, and interacted with mean annual temperature and precipitation. Soil pH mediated the filtering effects of climate and sand content on SLA. Our results also revealed that communities characterized by a low variance can also exhibit low kurtosis values, indicating that functionally contrasting species can co-occur even in communities with narrow ranges of trait values. 4. Synthesis We identified the particular set of conditions under which the environmental filtering hypothesis operates in drylands worldwide. Our findings also indicate that species with functionally contrasting strategies can still co-occur locally, even under prevailing environmental filtering. Interactions between sources of environmental stress should be therefore included in global trait-based studies, as this will help to further anticipate where the effects of environmental filtering will impact plant trait diversity under climate change.

The expected link between competitive exclusion and community trait overdispersion has been used to infer competition in local communities, and trait clustering has been interpreted as habitat filtering. Such community assembly process inference has received criticism for ignoring trophic interactions, as competition and trophic interactions might create similar trait patterns. While other theoretical studies have generally demonstrated the importance of predation for coexistence, ours provides the first quantitative demonstration of such effects on assembly process inference, using a trait-based ecological model to simulate the assembly of a competitive primary consumer community with and without the influence of trophic interactions. We quantified and contrasted trait dispersion/clustering of the competitive communities with the absence and presence of secondary consumers. Trophic interactions most often decreased trait clustering (i.e. increased dispersion) in the competitive communities due to evenly distributed invasions of secondary consumers and subsequent competitor extinctions over trait space. Furthermore, effects of trophic interactions were somewhat dependent on model parameters and clustering metric. These effects create considerable problems for process inference from trait distributions; one potential solution is to use more process-based and inclusive models in inference.

In forest succession, the ecological strategies of the dominant species that are based on functional traits are important in the determination of both the mechanisms and the potential directions of succession. Thirty-one plots were established in the Loess Plateau region of northern Shaanxi in China. Fifteen leaf traits were measured for the 31 dominant species that represented the six stages of succession, and the traits included four that were related to morphology, seven to stoichiometry and four to physiological ecology. The species from the different successional stages had different patterns of distribution of the traits, and different key traits predicted the turnover of the species during succession. The ash and the cellulose contents were key regulatory factors of species turnover in the early successional communities, and the trait niche forces in sugar and leaf dry mass content might become more important with the progression of succession. When only the three herb stages were considered, a progressive replacement of the ruderal by the competitive-ruderal species occurred in the intermediate stages of succession, which was followed by the stress-tolerant-competitive or the competitive-stress tolerant-ruderal strategists late in the succession. Thus, the different species that occurred in the different stages of succession shared different trait-based ecological strategies. Additionally, these differences occurred concomitantly with a shift toward competitive-stress tolerant-ruderal strategies.