Shucun Sun

Parasitoid wasps can lay unfertilized eggs that develop into male offspring prior to mating. While most studies investigated the fitness of unmated oviposition under fixed host abundance, the costs and benefits of oviposition before mating may shift at low and high host availability. Furthermore, these studies typically focus on single parasitoid species, which limits their ability to explain patterns in broader parasitoid community structure. We compared differences in multiple life‐history traits and reproductive outcomes under varied host availability between mated and unmated females of two Drosophila parasitoids. Our results revealed key interspecific differences. Firstly, under sucrose‐fed conditions, mated Trichopria drosophilae Perkins (Hymenoptera: Diapriidae) females outlived unmated ones, whereas mated Pachycrepoideus vindemiae Rondani (Hymenoptera: Pteromalidae) females lived shorter than unmated ones. Secondly, when fed with pure water, mated T. drosophilae females survived for a shorter period than unmated females, whereas in P. vindemiae , unmated females survived longer than mated ones only under low host availability. Thirdly, fecundity of female T. drosophilae was unaffected by mating status, but mated P. vindemiae produced substantially fewer offspring than unmated ones. This may reflect altered reproductive allocation after mating in P. vindemiae , whereas unmated females produce only male offspring. Fecundity increased with host availability for both species. The divergence in how mating status affects the life‐history traits of two parasitoid species reflects their different reproductive allocation strategies, with reproductive responses further modulated by host availability. Our study underscores the need for broader research on unmated oviposition behavior across parasitoid species, as this reproductive strategy may influence offspring sex allocation, population dynamics, and biological control efficacy, with important ecological and evolutionary consequences under natural conditions.

Seasonal thermal fluctuation is a dominant environmental force in temperate ecosystems, yet its role in shaping community dynamics and persistence remains poorly understood. We addressed this question by tracking high‐resolution seasonal dynamics of a model system composed of host Drosophila flies and two parasitoid species attacking hosts at larval and pupal stages respectively. Both parasitoid species increased in abundance steadily during the spring. The pupal parasitoid declined in summer but resurged in autumn, whereas the larval parasitoid declined after a summer peak. The host population remained relatively stable after an initial spring increase. Modelling predicted that the system would collapse under constant cool environments due to excessive parasitism on hosts, whereas pupal parasitoids would be excluded under constant warmth. These predictions were validated by controlled laboratory mesocosm experiments. Life history assays clearly revealed that cool and warm seasons favour different parasitoid species: cooler temperatures resulted in higher mortality of immature larval parasitoids due to host immunity, whereas warmer temperatures narrowed the host exposure window and increased mortality of immature pupal parasitoids. These results demonstrate that seasonal temperature fluctuation maintains a fragile multi‐trophic motif by preventing resource overexploitation and competitive exclusion, highlighting that intra‐annual periodic forcing sustains biodiversity.

Global warming can alter not only the seasonal timing of animal activity but also daily activity, a fundamental dimension of animal behavior with important consequences for energy acquisition and species performance. Although studies have focused predominantly on global warming effects on animal phenology, the effects on daily activity remain largely unexplored. Here, we used long-term field experimental warming with large open-top chambers (15 × 15 × 2.5 m), which increased temperatures by 0.24 °C in the growing season and 0.55 °C in the non-growing season from 2017 to 2023, to determine whether warming alters daily activity time, body mass, and species abundance of the crepuscular slug Agriolimax agrestis in an alpine meadow on the eastern Tibetan Plateau. Experimental warming increased slug activity time by 37 min (+ 25%) in 2022 and 50 min (+ 29%) in 2023, and increased body mass by 65% and 57%, respectively, without changing growth phenology. To determine whether warming could directly affect slug activity time and growth, we conducted a complementary, short-term (18 days in August) experiment using small open-top chambers (2 × 2 × 2 m), which elevated temperature by 0.44 °C. Warming increased slug activity time by 180% and body mass by 36%, which was consistent with the result of the long-term experiment. Slug abundance increased by an average of 497% in warmed plots from 2019 to 2023, likely driven by enhanced survival and increased fecundity, both of which might be associated with increased body mass. Overall, warming substantially extends the slug daily activity time, with possible consequences of increased body mass and abundance, highlighting an overlooked mechanism by which climate warming may influence animal traits and demographics in cold regions.

Although arthropods are key agents of detritus decomposition, the extent to which environmental heterogeneity modulates this process through shifts in community composition remains poorly understood, particularly in high‐elevation ecosystems. We examined animal‐derived detritus (yak carrion) decomposition on the Qinghai–Tibet Plateau, partitioning direct spatial (grassland, shrubland, riverbank and wetland) and temporal effects (July–September) from those mediated by arthropod assemblages. Our results reveal that species richness and abundance varied significantly among habitats and sampling months, with species richness highest in grasslands, particularly in July, whereas abundance peaked in shrublands, especially in September. Multivariate analyses revealed pronounced habitat‐level differentiation in arthropod community composition and strong associations with environmental variables, especially vegetation richness. Decomposition rates (K) were substantially higher in grassland and shrubland than in riverbank and wetland habitats, peaking in July for grasslands and in September for shrublands. Structural equation modelling (SEM) revealed that decomposition was directly driven by habitat type rather than indirectly through arthropod richness and abundance, demonstrating that environmental heterogeneity on the Qinghai–Tibet Plateau dominates over biodiversity effects on ecosystem functioning and highlighting the context‐dependent nature of arthropod‐mediated decomposition.

Rapid urbanization exerts profound pressure on urban biodiversity, yet long-term assessments integrating multi-source remote sensing data remain scarce. Objective: Focusing on the Hangzhou Bay Urban Agglomeration, a rapidly developing region in China’s Yangtze River Delta, this study aims to construct a remote sensing-based Biodiversity Index (BI) and analyze its spatiotemporal evolution and underlying drivers. Six Essential Biodiversity Variables derived from satellite observations (2000–2024) were integrated using Principal Component Analysis. Spatial autocorrelation and Geodetector models were then applied to examine BI dynamics and driving factors. The regional BI declined gradually from 0.80 in 2000 to 0.72 in 2024, with the rate of decline slowing after 2020 and a partial recovery observed in Zhoushan. Marked inter-city heterogeneity exists: Huzhou retains the highest and most stable BI due to extensive forest cover, whereas Jiaxing exhibits the lowest BI and the most pronounced decline, driven by rapid expansion of construction land. Land use/cover (LULC) and fractional vegetation cover (FVC) emerge as the dominant drivers (average q-values of 0.196 and 0.208, respectively), and their interaction explains over 46% of the spatial variance in BI. Road density shows a consistently increasing influence over time. This study demonstrates the utility of remote sensing-based frameworks for monitoring urban biodiversity dynamics and provides actionable insights for evidence-based land use planning and ecological restoration.

During crop growth, leaf photosynthetic capacity changes continuously, and the vertical distribution of leaf nitrogen (N_a, in g m⁻²) and chlorophyll (Chl_a, in μg cm⁻²) affects photosynthesis in different canopy layers. Understanding stratified photosynthesis is vital for the accurate prediction of crop photosynthetic capacity. We conducted a two-year field study on winter wheat and paddy rice in Eastern China, measuring the leaf maximum carboxylation rate (V_cmax25), maximum electron transport rate (J_max25), N_a, and Chl_a every 7–10 days from greening to maturity. We analyzed vertical variations in these parameters in the upper (T-1), middle (T-2), and lower (T-3) canopy layers and explored relationships between N_a/Chl_a and V_cmax25. The results showed significant vertical variations: V_cmax25 and J_max25 in T-1 were higher than in T-2, and T-2 was higher than T-3. The vertical distribution of N_a and V_cmax25 was more pronounced than that of Chl_a. The correlation between N_a and V_cmax25 increased from T-1 to the lower layers, while the V_cmax25-Chl_a correlation decreased. A single V_cmax25 estimation model based on N_a performed well across layers (R² = 0.619, RMSE = 15.751 µmol m⁻² s⁻¹). Differentiating T-1 from T-2/T-3 improved the Chl_a-based models. N_a was better than Chl_a for characterizing the V_cmax25 vertical variation, with the Chl_a-based models requiring separation of T-1 from T-2/T-3. This study provides key insights for remote sensing of photosynthetic parameters and improves the understanding of crop canopy photosynthesis.

During crop growth, leaf photosynthetic capacity changes continuously, and the vertical distribution of leaf nitrogen (Na) and chlorophyll (Chla) affects photosynthesis in different canopy layers. Understanding stratified photosynthesis is vital for accurate prediction of crop photosynthetic capacity. We conducted a two-year field study on winter wheat and paddy rice in Eastern China, measuring leaf maximum carboxylation rate (Vc_max25), maximum electron transport rate (J_max25), Na, and Chla every 7–10 days from greening to maturity. We analyzed vertical variations of these parameters in upper (T-1), middle (T-2), and lower (T-3) canopy layers and explored relationships between Na/Chla and Vc_max25. Results showed significant vertical variations: Vc_max25 and J_max25 in T-1 were higher than T-2, and T-2 higher than T-3. The vertical distribution of Na and Vc_max25 was more pronounced than Chla. Correlation between Na and Vc_max25 increased from T-1 to lower layers, while Vc_max25-Chla correlation decreased. A single Vc_max25 estimation model based on Na performed well across layers (R²=0.619, RMSE=15.751 µmol m⁻² s⁻¹). Differentiating T-1 from T-2/T-3 improved Chla-based models. Na was better than Chla for characterizing Vc_max25 vertical variation, with Chla-based models requiring separation of T-1 from T-2/T-3. This study provides key insights for remote sensing of photosynthetic parameters and improves understanding of crop canopy photosynthesis.

Although numerous studies have documented the differences in leaf fungal endophyte (LFE) communities among various plant species inhabiting the same environments, the disparities in LFE among distinct species groups have rarely been examined at the community level. The composition and structure of the LFE community are known to be influenced by the abundance of host plants and the leaf functional traits at the species level. Given that various plant functional groups exhibit differences in relative abundance and leaf functional traits, we hypothesize that these distinct plant functional groups may support unique LFE communities, which are likely correlated with their specific functional demands. In this study, we investigated LFE community across 45 plant species, which were categorized into four functional groups: grasses, legumes, dicot forbs, and monocot forbs from an alpine meadow, utilizing high‐throughput sequencing techniques. We assessed the differences in LFE among the plant functional groups and analyzed these differences in relation to plant abundance and leaf functional traits. The LFE community exhibited significant differences among plant functional groups. The dicot forbs demonstrated a higher richness of LFE compared to the other three functional groups. Ascomycota was found to be the dominant phylum across all plant functional groups. Additionally, marker operational taxonomic units (OTUs) associated with a symbiotic lifestyle were more prevalent in legumes than in the other three functional groups. Leaf mass per area is identified as the primary determinant of variation in LFE community across different plant functional groups, with water content and leaf nitrogen concentration serving as secondary factors. Furthermore, species abundance also plays a significant role in explaining the variation observed in LFE. Our research enhances the understanding of microbial‐plant interactions and indicates a potential role of LFEs in shaping community structure and dynamics.

Disparities in root fungal endophyte (RFE) communities are well documented among plant species, yet differences among plant functional groups (PFGs) remain unclear. Given that RFE community structure is influenced by host plant abundance and species-specific root functional traits, and that PFGs exhibit divergent relative abundances and root traits, we hypothesize that PFGs harbor unique RFE communities, potentially aligned with their functional traits. We investigated RFE communities in 45 alpine meadow species representing four PFGs (grasses, legumes, dicot forbs, and monocot forbs), using high-throughput sequencing. Ascomycota dominated all groups (>50%) except monocot forbs (38.9%). Distinct differences in the RFE community species composition were found among PFGs. In particular, the differences were significant between dicot forbs and monocot forbs, and between monocot forbs and grasses, which contradicted with conventional PFG classification that combined monocot and dicot forbs as a single PFG. Moreover, marker operational taxonomic units (OTUs) with symbiotic lifestyles were more abundant in legumes, and their functional composition differed significantly from grasses. Roots’ nitrogen concentration was the strongest predictor of RFE variation, followed by root length, biomass, and species abundance. These results emphasize the importance of integrating microbial partners into understanding plants’ functional diversity and ecosystem resilience in alpine environments.

Unveiling the enigmatic processes underlying the rapid disappearance of arthropod corpses in nature is not only fascinating but also essential for understanding their ecological fate. Functional traits retained in freshly dead arthropods may influence their consumption by invertebrate scavengers. To validate this idea, we conducted a field trapping survey using four types of baits (arthropod corpses, yak carrion, yak dung, and horse dung) to investigate the attraction of arthropod corpses to necrophagous beetles in a Tibetan alpine meadow, complemented by a laboratory experiment to further examine the scavenging behavior of three necrophagous beetle species (i.e., Thanatophilus rugosus , Nicrophorus sinensis , and Nicrophorus investigator ) on 25 species of dead arthropods. Results show that arthropod corpses can attract necrophagous beetles, albeit with lower species richness and abundance compared to yak carrion in the Tibetan alpine meadow. All the three necrophagous beetle species exhibited a preference for arthropod corpses with higher internal water content, lower exoskeleton content, and intermediate body size. In addition, the beetles preferentially consumed the abdomen with lower exoskeleton content to the thorax and head during partial consumption. These findings suggest that internal water content, exoskeleton content, and body size of arthropod corpses significantly influence the scavenging behavior of necrophagous beetles, thereby highlighting the importance of animal functional traits in shaping predator‐prey interactions within scavenger communities.