Non-senescent species are not immortal: Stress and decline in two planaria species.

Potential immortality is observed in several species (e.g. prickly pear cactus, hydra and flatworms) and is indicative of their negligible or even negative senescence rates. Unlike in senescent species, which experience reduced individual performance with age due to physiological degradation, species with negligible or negative senescence display mortality rates that remain constant or decline with age, respectively. These rates vary across taxa and are correlated with life history traits. Yet, the extent to which variable resource availability, a key driver of variation in life history traits, impacts species that show negligible or negative senescence is currently unknown. Here, we examine whether and how variation in the quantity, quality and feeding interval of resources impact population structure, population performance and life history trait trade-offs in two long-lived planaria that do not senesce: Schmidtea mediterranea and Dugesia tahitiensis. In a full factorial design, different combinations of resource quantity (reduced intake, standard intake and high intake) and quality (high and low quality) were provided in two different feeding intervals (7-day and 14-day intervals) for 19 weeks. We show that variability in resource availability, via decreases in quantity, quality and frequency of resources, does not diminish population viability in either species but does result in suboptimal conditions of stress in S. mediterranea. The high population viability we report can be attributed to two different mechanisms: increased reproduction or increased investment into maintenance at the expense of reproduction. Moreover, which mechanism was responsible for said high population viability was context-dependent and modulated by the specific life history strategy of the two planaria species. We show that suboptimal conditions can cause stress responses that have significant impacts on non-senescent species. The context-dependent response we observe suggests that species that do not senesce but are subject to suboptimal conditions of stress may ultimately exhibit declines in performance and ultimately die. A clearer understanding of the impact of suboptimal conditions of resource availability on non-senescent species is needed to determine the extent of stress experienced and ultimately whether a species can truly be immortal.

A new dataset on climate distance for trade analyses.

This data article describes a new dataset on measures of climate distance for trade analyses. The dataset contains, (i) time-varying measures of long-run climate conditions for twenty economies accounting for two-third of global agri-food exports and representatives of different prevailing climates, and (ii) the difference in long-run climate conditions between country-pairs, here defined as Climate Distance. Measures of long-run climate conditions are computed, for each year in the sample (1996 to 2015), as 30-years rolling averages of weather conditions (i.e., climate normals or climatologies) in each country. Our climate measures are based on elaboration of data collected from the World Bank's Climate Change Knowledge Portal (CCKP), containing historical information on weather conditions. We also provide data on bilateral trade flows, tariffs, and policies, as provided by publicly available datasets. Our measures of climate change allow a more precise evaluation of structural changes in trade routes associated with climate comparative advantages.

"Data Free Flow with Trust": Japan's struggle to integrate democracy and human rights into digital trade policy.

A powerful regime for regulating trade, the Group of Seven (G-7) has increasingly negotiated its digital trade through bilateral and preferential trade agreements, including with non-member states in the Global South. Focusing on the dominant concept shaping these agreements, Japan's "Data Free Flow with Trust" (D.F.F.T.), we trace its discursively contested emergence and meaning within a national ("Society 5.0") vision for Japan's digital transformation, and its subsequent transnationalization in international fora and institutionalization in global digital trade policy. Drawing on our interviews with Japanese government ministers, business elites, and legal experts who contributed to the processual development of D.F.F.T., as well as diverse additional primary sources, we find that the D.F.F.T. has become more than a trade policy, covering a wider range of social and geopolitical issues. In particular, we show that contention over "data localization measures" has restructured international relations of trust, especially across the Global North/South divide. Ultimately, this research report contributes to our understanding of how D.F.F.T. poses threats to human rights, democracy, and the global knowledge economy that may undermine its goals of enhancing innovation capacity and economic growth.

Grindr? it's a "Blackmailer's goldmine"! The weaponization of queer data publics Amid the US-China trade conflict.

In March 2019, the Committee on Foreign Investment in the United States (CFIUS) identified Grindr, a hookup app that predominantly caters to men who have sex with men, as a "national security threat" and compelled the Chinese conglomerate Kunlun Tech to divest from it entirely. The CFIUS-Grindr ruling is indicative of larger regulatory debates over increasing datafication trends in the dating app industry. Through a political economy approach to communication, this paper examines how this ruling was predominantly constructed by various stakeholders as a public controversy in light of the ongoing US-China trade conflict. This interpretation of the controversy relies on a prejudicial trope that construes queer dating app users as vulnerable targets of potential blackmail schemes operated by Chinese intelligence agencies. Through the Lavender Scare, a historical period referring to state-led investigations into the presence of LGBTQ+ employees in Western federal workforces, this paper historicizes this blackmail trope to highlight how the politicization of queer vulnerabilities amid global hegemonic conflicts is a tactic that predates the US-China trade conflict. It argues that the CFIUS-Grindr ruling weaponizes Grindr's queer data publics as threats against which the US government should protect itself, while failing to fully recognize the urgency for the state to protect the data privacy rights of the LGBTQ+ communities in the digital economy. In light of the CFIUS-Grindr ruling, this paper examines the implications that datafication raises for the LGBTQ+ communities whose sexual lives and identities are increasingly being datafied and exploited by digital media platforms.

Finding a balance: Reproductive trade-offs in parasitic isopods of the family Cymothoidae.

In this study conducted along the coast of Odisha, India, reproductive trade-offs in isopods of the family Cymothoidae were investigated, focusing on the relationship between the number vs. volume of eggs and the percentage of brood to body volume. Ovigerous females from species with substantial sample sizes (n > 30) were analyzed to understand their survival strategies. The findings highlight distinct strategies among different parasite types within Cymothoidae. Buccal parasites such as Cymothoa frontalis and Cymothoa indica, along with branchial parasites like Joryma sawayah and Agarna malayi, generally produced a higher number of smaller eggs, except for A. malayi, which produced fewer but larger eggs. In contrast, the external body surface-attaching parasite, Nerocila orbignyi, was observed to produce fewer eggs of larger size. Across all parasite types (intraspecific), there was a statistically significant negative correlation between egg number and egg volume (p < 0.05). Buccal parasites were observed to have the highest percentage of marsupium volume relative to body volume, indicating a strategy to maximize egg storage. Conversely, external body surface-attaching parasites had the lowest percentage, possibly reflecting adaptation to a different reproductive environment. Additional observations revealed anatomical adaptations in all the studied isopod species which include the shift of the alimentary canal to the dorsal side to accommodate the development of the marsupial sac for egg incubation. In summary, these findings illustrate how parasitic isopods of the family Cymothoidae manage trade-offs between reproductive potential and success, crucial for their species' continuity and survival strategies in coastal ecosystems.

The effects of pressure on anticipatory postural adjustments during a jump shot in basketball.

BACKGROUND: Anticipatory postural adjustments (APAs) play an important role in feedforward control of dynamic movements, such as jump shot performance in basketball. It is known that jump shot performance declines under pressure from a defender (shot blocker). RESEARCH QUESTION: Does pressure from a shot blocker affect the APAs of a jump shot in basketball? Is jump shot performance in basketball associated with APAs? METHODS: Fourteen healthy male university basketball players performed jump shots under pressure and non-pressure (free) conditions by a shot blocker. Using a force plate, the APAs were defined as occurring until the point of thrust (TH) phase, and ground reaction force (GRF) and center of pressure (COP) at that moment were assessed. To assess jump shot performance, the maximum GRF during the TH phase (THmax), jumping height, and success score of the shot (accuracy score: AS) were measured by using the vertical component of the force plate. Two-way ANOVA examined the effects of the phase and condition on APA duration. The effects of pressure from a shot blocker on each variable (subjective pressure intensity, AS, GRF, and COP) were analyzed using a pairwise t-test or Wilcoxon signed-rank tests. Relationships between changes in jump shot performance and GRF or COP variables were assessed via Spearman's correlation analysis. Differences between the pressure and free conditions were denoted by p/f (pressure/free). RESULTS: The APA duration was shorter under the pressure condition compared to the free condition. The THmax and jump height values were greater under the pressure condition relative to the free condition. Across conditions, changes in COP sway velocity of the APA phase were significantly and negatively correlated with AS. SIGNIFICANCE: The results of this study suggest that pressure from a shot blocker shortens APA duration and decreases jump shot performance.

Productive Poplar Genotypes Exhibited Temporally Stable Low Stem Embolism Resistance and Hydraulic Resistance Segmentation at the Stem-Leaf Transition.

Breeding tree genotypes that are both productive and drought-resistant is a primary goal in forestry. However, the relationships between plant hydraulics and yield at the genotype level, and their temporal stabilities, remain unclear. We selected six poplar genotypes from I-101 (Populus alba) × 84 K (P. alba × Popolus tremula var. glandulosa) for experiments in the first and fourth years after planting in a common garden. Measurements included stem embolism resistance, shoot hydraulic resistance and its partitioning between stems and leaves, vessel- and pit-level anatomy, leaf carbon acquisition capacity, carbon allocation to leaves, and aboveground biomass (yield proxy). Significant genetic variations in hydraulic properties and yield were found among genotypes in both years. Productive genotypes had wide vessels, large thin pit membranes, small pit apertures, and shallow pit chambers. Hydraulic resistance was negatively correlated with yield, enabling high stomatal conductance and assimilation rates. Productive genotypes allocated less aboveground carbon and hydraulic resistance to leaves. Temporally stable trade-offs between stem embolism resistance and yield, and between hydraulic segmentation and yield, were identified. These findings highlight the tight link between hydraulic function and yield and suggest that stable trade-offs may challenge breeding poplar genotypes that are both productive and drought-resistant.

The meteorological drivers of mass coral bleaching on the central Great Barrier Reef during the 2022 La Niña.

The frequencies of marine heatwaves and thermal coral bleaching events (CBEs) over the Great Barrier Reef (GBR) continue to increase with five mass CBEs reported since 2016. While changes in the local meteorology, such as reduced wind speeds and decreased cloud cover, are known to heat the shallow reef waters, little consideration has been given to the overriding synoptic meteorology. The 2022 CBE, occurring under La Niña conditions, saw ocean temperatures at Davies Reef increase 1.9 ∘ C over 19-days and subsequently cool 2.1 ∘ C back to seasonal norms over eight days. This event was found to be triggered by repeated Rossby wave breaking disrupting the local trade winds, thus inhibiting the latent heat flux. Latent heat fluxes, the primary driver of the event, tripled as the trade winds returned via rapid coastal ridging. These same synoptic features are concurrent with the historic Lismore flooding located hundreds of kilometres south of the GBR.

Targeted opportunities to mitigate water scarcity, inequality, and inequity embedded in international food trade for vulnerable countries.

International food trade reshapes regional water scarcity through virtual water transfers (VWT), influencing water use equality and equity. This study examines eight populous yet impoverished countries in Africa and Asia, representing 30 % of the global poor population and contributing 20 % to agricultural VWT. Despite their significant role, these countries have been understudied due to a lack of data or attention. By integrating multiple datasets and models, we assess how international food trade impacts water scarcity, inequality, and inequity within these countries and identify the driving factors. Our findings reveal varied outcomes: Uganda and Ethiopia benefit from reduced water scarcity (∼40 % and ∼7 %) and improved equality and equity (∼90 % and ∼68 %), while India and Pakistan face exacerbated scarcity (∼4 % and ∼2 %) and widening inequality and inequity (∼4 % and ∼7 %). The effects are largely driven by critical trade flows of staple and cash crops like rice, sugar cane, and cotton among developing countries, propelled by comparative advantages in agricultural production, econo-geography, food demand, and water endowment between importers and exporters. Addressing these water challenges involves diversifying import channels to reduce reliance on detrimental trade flows, such as India's rice exports to Iran, while promoting beneficial flows, like Bangladesh's cotton imports from India, through trade agreements. Additionally, implementing pro-poor water policies (e.g., providing water subsidies) and water-saving techniques (e.g., adopting drip irrigation) is crucial, though caution is needed to avoid unintendedly marginalizing vulnerable groups through large-scale water projects.

Norm Entrepreneurship in Digital Trade: The Singapore-led Wave of Digital Trade Agreements.

Rulemaking in digital trade is proceeding apace. Many preferential trade agreements contain dedicated e-commerce or digital trade chapters and some states have entered into stand-alone digital economy agreements. This article seeks to establish whether, and to what extent, normative change is occurring in digital trade agreements, the nature of any changes, and identify which states are acting as norm entrepreneurs. We employ a new method of legal coding, systematically comparing the nature and prescriptiveness of digital provisions in 12 trade agreements concluded between 2019 and 2023. We find evidence of substantial policy innovation, and identify Singapore as the key norm entrepreneur. A new wave of 'Singapore-led' agreements substantially expands the scope of digital trade, to cover areas such as digital identities, e-invoicing and e-payments, the governance of AI, and regulation of new digital technologies. Commitments are typically couched as soft rather than hard law, reflecting the nascent stages of rulemaking. Norm entrepreneurship on the part of Singapore and its allies reflects a desire to position themselves as 'digital hubs' in the global economy, spur rulemaking in areas where innovation is ahead of regulation, and promote digital interconnectivity at time of regulatory divergence and geopolitical rivalry.

Evolutionary Adaptation in Heterogeneous and Changing Environments.

Organisms that are adapting to long term environmental change almost always deal with mul- tiple environments and trade-offs that affect their optimal phenotypic strategy. Here we combine the idea of repeated variation or heterogeneity, like seasonal shifts, with long-term directional dy- namics. Using the framework of fitness sets, we determine the dynamics of the optimal phenotype in two competing environments encountered with different frequencies, one of which changes with time. When such an optimal strategy is selected for in simulations of evolving populations, we observe rich behavior that is qualitatively different from and more complex than adaptation to long-term change in a single environment. The probability of survival and the critical rate of environmental change above which populations go extinct depend crucially on the relative fre- quency of the two environments and the strength and asymmetry of their selection pressures. We identify a critical frequency for the stationary environment, above which populations can escape the pressure to constantly evolve by adapting to the stationary optimum. In the neighborhood of this critical frequency, we also find the counter-intuitive possibility of a lower bound on the rate of environmental change, below which populations go extinct, and above which a process of evolutionary rescue is possible.

Physiological costs of warning: Defensive hissing increases metabolic rate and evaporative water loss in a venomous snake.

To minimize predation risk and the cost of confronting predators, prey have developed a range of defensive strategies and warning signals. Although advantageous, defensive warnings may also induce physiological and energy costs to the emitter. Ventilatory sounds (hissing) are the most distributed warning sound in vertebrates. Because they involve the respiratory apparatus, defensive hissing may substantially increase evaporative water loss. Herein, we examined the determinants of hissing as well as its physiological costs in a medium-sized venomous snake, the long-nosed viper (Vipera ammodytes). We first used a neutral arena and applied standardized stimulation to measure the occurrence and acoustic characteristics of warning hissing. Then, we used open-flow respirometry to quantify changes in respiratory gas exchanges (oxygen consumption and evaporative water loss) during defensive responses. We demonstrated that males are more likely to engage in sound warnings when stimulated. Expirations generated the strongest signals compared to inspiration but did not differ between sexes. We found that defensive hissing dramatically increased average metabolic rate and evaporative water loss during the 10-minute stimulation period, and this effect was more pronounced in males. Metabolic rates and evaporative water loss were closely related to the duration of hissing. Overall, our results indicate that respiratory-based warning sounds induce significant physiological costs and may alter water balance. The higher responsiveness in males than females likely reflects sexually selective pressure (higher mobility for mate acquisition) and enhanced risk exposure.

Ship emission variations during the COVID-19 from global and continental perspectives.

The COVID-19 pandemic and the International Maritime Organization's (IMO) 2020 fuel-switching policy have profoundly impacted global maritime activities, leading to unprecedented changes in shipping emissions. This study aimed to examine the effects from different scales and investigate the underlying drivers. The big data model Ship Emission Inventory Model (SEIM) was updated and applied to analyze the spatiotemporal pattern of global ship emissions as well as the main contributors in 2019 and 2020. Overall, ships emitted NOx, CO, HC, CO2, and N2O declined by 7.4 %-13.8 %, while SO2, PM2.5, and BC declined by 40.9 %-81.9 % in 2020 compared with 2019. The decline in CO2 emissions indicated a comparable reduction across vessel tonnages. Ship emissions occurring at cruising status accounted for over 90 % of the ship's CO2 emission reduction. Container ships, chemical tankers, and Ro-Ro vessels were the primary contributors to the emission reductions, with container ships alone responsible for 39.4 % of the CO2 decrease. The ship's CO2 emissions variations revealed the decline-rebound patterns in response to the pandemic. Asian-related routes saw emissions drop in February 2020, followed by a rebound in May, while European and American routes experienced declines starting in May, with a recovery in August. Further analysis of CO2 emission in Exclusive Economic Zones (EEZs) showed high temporal consistency between vessel CO2 emissions, sailing speeds, and international trade volumes across continents, and exhibited heterogeneity in main contributing ship type of emission reduction on continental scale. Our study reveals the short-term fluctuation characteristics of global ship emissions during the pandemic, particularly focusing on their spatiotemporal evolution and the inherent disparities. The results highlight the correlation between global ship emissions and trade, as well as the operational status of ships, and their rigidity.

Trade-offs and thermodynamics of energy-relay proofreading.

Biological processes that are able to discriminate between different molecules consume energy and dissipate heat, using a mechanism known as proofreading. In this work, we thoroughly analyse the thermodynamic properties of one of the most important proofreading mechanisms, namely Hopfield's energy-relay proofreading. We discover several trade-off relations and scaling laws between several kinetic and thermodynamic observables. These trade-off relations are obtained both analytically and numerically through Pareto optimal fronts. We show that the scheme is able to operate in three distinct regimes: an energy-relay regime, a mixed relay-Michaelis-Menten (MM) regime and a Michaelis-Menten regime, depending on the kinetic and energetic parameters that tune transitions between states. The mixed regime features a dynamical phase transition in the error-entropy production Pareto trade-off, while the pure energy-relay regime contains a region where this type of proofreading energetically outperforms standard kinetic proofreading.

Evaluating Vacuum and Steam Heat to Eliminate Pinewood Nematodes in Naturally Infested Whole Pine Logs.

Pinewood nematodes threaten forest health and continue to interfere with international trade because they can be spread around the globe via nematode-infested wood. International Standards for Phytosanitary Measure (ISPM-15) requires that all pine wood be treated at 56°C for 30 min to ensure that all pests and pathogens are killed within sawn wood, whereas fumigation with methyl bromide is the currently approved practice and widely used in treating whole logs. A method of treatment that uses less energy and time or does not rely on environmentally damaging gases is urgently needed. Because vacuum with steam has shown promise in treating several different commodities, the purpose of this study was to use it to eradicate pinewood nematodes in whole logs. Three protocols were applied: 1) 48°C for 15 min., 2) 56°C for 30 min., and 3) 60°C for 60 min. The third protocol reduced the population to statistically zero; however, some samples contained at least 1 survivor. Unfortunately, these surviving nematodes increased in number one month after treatment, and one year later, they continued to reproduce in the wood. Therefore, this protocol needs to be further refined to remove pinewood nematodes completely. Explanation of the survival of individual nematodes within whole logs remains a matter for conjecture: 1) certain portions of the wood were somehow insulated from the heat and did not achieve the lethal temperature, and 2) survival stages may be able to survive temperatures that are deadly to the normal life stages.

Biological constraint, evolutionary spandrels and antagonistic pleiotropy.

Maximum lifespan differs greatly between species, indicating that the process of senescence is largely genetically determined. Senescence evolves in part due to antagonistic pleiotropy (AP), where selection favors gene variants that increase fitness earlier in life but promote pathology later. Identifying the biological mechanisms by which AP causes senescence is key to understanding the endogenous causes of aging and its attendant diseases. Here we argue that the frequent occurrence of AP as a property of genes reflects the presence of constraint in the biological systems that they specify. This arises particularly because the functionally interconnected nature of biological systems constrains the simultaneous optimization of coupled traits (interconnection constraints), or because individual traits cannot evolve (impossibility constraints). We present an account of aging that integrates AP and biological constraint with recent programmatic aging concepts, including costly programs, quasi-programs, hyperfunction and hypofunction. We argue that AP mechanisms of costly programs and triggered quasi-programs are consequences of constraint, in which costs resulting from hyperfunction or hypofunction cause senescent pathology. Impossibility constraint can also cause hypofunction independently of AP. We also describe how AP corresponds to Stephen Jay Gould's constraint-based concept of evolutionary spandrels, and argue that pathologies arising from AP are bad spandrels. Biological constraint is a conceptual missing link between ultimate and proximate causes of senescence, including diseases of aging.

Androgen-mediated maternal effects and trade-offs: postnatal hormone development, growth, and survivorship in wild meerkats.

Introduction: Mammalian reproductive and somatic development is regulated by steroid hormones, growth hormone (GH), and insulin-like growth factor-1 (IGF-1). Based largely on information from humans, model organisms, and domesticated animals, testosterone (T) and the GH/IGF-1 system activate sexually differentiated development, promoting male-biased growth, often at a cost to health and survivorship. To test if augmented prenatal androgen exposure in females produces similar developmental patterns and trade-offs, we examine maternal effects in wild meerkats (Suricata suricatta), a non-model species in which adult females naturally, albeit differentially by status, express exceptionally high androgen concentrations, particularly during pregnancy. In this cooperative breeder, the early growth of daughters predicts future breeding status and reproductive success. Methods: We examine effects of normative and experimentally induced variation in maternal androgens on the ontogenetic patterns in offspring reproductive hormones (androstenedione, A4; T; estradiol, E2), IGF-1, growth from pup emergence at 1 month to puberty at 1 year, and survivorship. Specifically, we compare the male and female offspring of dominant control (DC or high-T), subordinate control (SC or lower-T), and dominant treated (DT or blocked-T) dams, the latter having experienced antiandrogen treatment in late gestation. Results: Meerkat offspring showed sex differences in absolute T and IGF-1 concentrations, developmental rates of A4 and E2 expression, and survivorship - effects that were sometimes socially or environmentally modulated. Atypical for mammals were the early male bias in T that disappeared by puberty, the absence of sex differences in A4 and E2, and the female bias in IGF-1. Food availability was linked to steroid concentrations in females and to IGF-1, potentially growth, and survival in both sexes. Maternal treatment significantly affected rates of T, E2, and IGF-1 expression, and weight, with marginal effects on survivorship; offspring of DT dams showed peak IGF-1 concentrations and the best survivorship. Discussion: Maternal effects thus impact offspring development in meerkats, with associated trade-offs: Whereas prenatal androgens modify postnatal reproductive and somatic physiology, benefits associated with enhanced competitiveness in DC lineages may have initial costs of reduced IGF-1, delay in weight gain, and decreased survivorship. These novel data further confirm the different evolutionary and mechanistic pathways to cooperative breeding and call for greater consideration of natural endocrine variation in both sexes.

Collaborative Joint Perception and Prediction for Autonomous Driving.

Collaboration among road agents, such as connected autonomous vehicles and roadside units, enhances driving performance by enabling the exchange of valuable information. However, existing collaboration methods predominantly focus on perception tasks and rely on single-frame static information sharing, which limits the effective exchange of temporal data and hinders broader applications of collaboration. To address this challenge, we propose CoPnP, a novel collaborative joint perception and prediction system, whose core innovation is to realize multi-frame spatial-temporal information sharing. To achieve effective and communication-efficient information sharing, two novel designs are proposed: (1) a task-oriented spatial-temporal information-refinement model, which filters redundant and noisy multi-frame features into concise representations; (2) a spatial-temporal importance-aware feature-fusion model, which comprehensively fuses features from various agents. The proposed CoPnP expands the benefits of collaboration among road agents to the joint perception and prediction task. The experimental results demonstrate that CoPnP outperforms existing state-of-the-art collaboration methods, achieving a significant performance-communication trade-off and yielding up to 11.51%/10.34% Intersection over union and 12.31%/10.96% video panoptic quality gains over single-agent PnP on the OPV2V/V2XSet datasets.

A Snapshot of the Global Trade of South African Native Vertebrate Species Not Listed on CITES.

The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) aims to prevent the overexploitation of species by controlling their trade. However, there is currently no international regulatory framework to protect the trade of non-CITES species. We examined the LEMIS database, online trade, and scientific literature with the aim of identifying and compiling a list of South African native species traded as pets and wildlife products. We found that there are 223 non-CITES species traded as wildlife products and 95 species traded as pets. Mammals and birds were the most traded taxa for wildlife products, while reptiles and amphibians were mostly traded as pets. At the least, species traded as wildlife products and pets are currently not facing extinction, as most are categorized as Least Concern. However, some endemic species have an unknown population size, with Sclerophrys pantherina and Neamblysomus gunningi being Endangered. The international pet trade involves 10 countries, with the USA, the Czech Republic, and the UK being the largest importers. The trade of species as wildlife products involves 20 countries, with the USA being the major importer. This study emphasizes the necessity of strict regulations and international cooperation to control the wildlife trade effectively.

Aged rather than pristine polyvinyl chloride microplastic affect the development and structure of Vallisneria natans population.

A large number of microplastics have been discharged into freshwater ecosystems, where they age and are deposited in the sediment, posing a risk to primary producers, such as submerged macrophytes. Many macrophytes benefit from clonal integration, which lets the population work as a 'macro' organism. Nonetheless, little is known about the differences in phytotoxicity between aged and pristine microplastics, particularly for clonal populations of macrophytes. In this study, we showed that UV-aging changes the characteristics of polyvinyl chloride microplastics (PVC-MPs). Aged PVC-MPs possessed higher hydrophilicity, less chlorine and crystallinity, and more severe toxicity. The pristine PVC-MPs did not affect Vallisneria natans, while the aged PVC-MPs significantly affected the development and structure of the clonal population. The severely aged PVC-MPs reduced the relative growth rate of V. natans by 26 % at the population level. Furthermore, the mother plant (ortet) and offspring (ramet) responded differently to the aged PVC-MPs. A trade-off was observed between the growth rate and stress resistance in the ortets. The ortets increased investment in the root part to tolerate stress when facing exposure to microplastics. In contrast, the ramets were less resistant, as shown by shorter roots, and lower leaf chlorophyll, carbon, and nitrogen concentrations. Notably, the growth of the ramets was maintained and the investments in stolon structure by the ortets were not lessened. The ortet sacrificed itself for the continuation of the ramet. This clonal integration may safeguard V. natans survival and compensate for vegetative expansion. This study sheds new light on how macrophytes respond to microplastics at the clonal population level and provides direct evidence that existing studies may have underestimated the toxic effect of microplastics in freshwater ecosystems.