Soil Cd increased the leaf litter Cd remains of Solanum nigrum and Solanum lycopersicum.

Plant litter decomposition is a natural pathway of heavy metal cycling in soil ecosystems, but the dynamics of heavy metal release during litter decomposition are relatively poorly understood. The purpose of this study was to investigate the effects of species, soil fauna and soil Cd addition on litter decomposition and Cd release dynamics. Therefore, we selected two plants, Solanum nigrum and S. lycopersicum with large differences in Cd accumulation capacity. First, they were enriched with Cd during the growing period and leaf litter was harvested after 6 months of pretreatment. Then, the decomposition of leaf litter was conducted with or without soil Cd and Eisenia fetida through lab pot tests. Our results showed that leaf litter Cd led to a significant decrease in litter decomposition rate (K value), with a maximum decrease of 32.1% in S. nigrum and 30.1% in S. lycopersicum. We observed that the presence of E. fetida significantly increased K value, but the effect was similar in the +leaf Cd treatment and the -leaf Cd treatment, both for S. nigrum and S. lycopersicum. Interestingly, the litter Cd concentration did not decrease during decomposition, but showed an increasing trend, especially for S. nigrum in the +soil Cd treatment. Moreover, the litter Cd remains was higher in the +soil Cd treatment compared to the -soil Cd treatment for both S. nigrum and S. lycopersicum, no matter whether with or without E. fetida. This result suggests that the Cd may be transferred from soil to litter, thus increasing the litter Cd remains. Overall, our study shows that leaf litter Cd slowed down the carbon cycling in ecosystems. In addition, the release of litter Cd has a lag, and the litter has a certain adsorption capacity for soil Cd, which intensifies the harm to the ecology during litter transfer.

Challenges and opportunities in human dimensions behind cat-wildlife conflict.

Because global anthropogenic activities cause vast biodiversity loss, human dimensions research is essential to forming management plans applicable to biodiversity conservation outside wilderness areas. Engaging public participation is crucial in this context to achieve social and environmental benefits. However, knowledge gaps remain in understanding how a balance between conservation and public demands can be reached and how complicated sociocultural contexts in the Anthropocene can be incorporated in conservation planning. We examined China's nationwide conflict between free-ranging cats (owned cats that are allowed to go outdoors or homeless cats living outdoors) and wildlife to examine how a consensus between compassion and biodiversity conservation can help in decision-making. We surveyed a random sample of people in China online. Over 9000 questionnaires were completed (44.2% response). In aggregate, respondents reported approximately 29 million free-ranging owned cats and that over 5 million domestic cats per year become feral in mainland China. Respondents who were cat owners, female, and religious were more likely to deny the negative impacts of cats on wildlife and ongoing management strategies and more supportive of stray cat shelters, adoption, and community-based fund raising than nonowners, male, and nonreligious respondents (p < 0.05). Free-ranging cat ownership and abandonment occurred less with owners with more knowledge of biodiversity and invasive species than with respondents with less knowledge of these subjects (p < 0.05). We recommend that cat enthusiasts and wildlife conservationists participate in community-based initiatives, such as campaigns to keep cats indoors. Our study provides a substantially useful framework for other regions where free-ranging cats are undergoing rapid expansion.

Retos y oportunidades de las dimensiones humanas detrás del conflicto entre gatos y fauna Resumen Debido a que las actividades antropogénicas globales causan una enorme pérdida de la biodiversidad, la investigación sobre las dimensiones humanas es esencial para generar planes de manejo aplicables a la conservación de la biodiversidad fuera de las áreas silvestres. Es muy importante lograr que el público participe en este contexto para obtener los beneficios sociales y ambientales. Sin embargo, todavía existen vacíos en el conocimiento sobre cómo lograr el balance entre la conservación y las demandas públicas y cómo incorporar los contextos socioculturales complejos del Antropoceno a la planeación de la conservación. Analizamos el conflicto nacional entre los gatos libres (gatos callejeros o gatos domésticos que se les permite salir) y la fauna en China para estudiar cómo un consenso entre la compasión y la conservación de la biodiversidad puede ayudar en la toma de decisiones. Encuestamos en línea a una muestra aleatoria de personas en China. Se completaron más de 9000 cuestionarios (44.2% de respuesta). En total, los respondientes reportaron un aproximado de 29 millones de gatos libres y que más de cinco millones de gatos domésticos se vuelven ferales al año en China. Quienes respondieron y son dueños de gatos, mujeres y religiosos tuvieron la mayor probabilidad de negar los impactos negativos de los gatos sobre la fauna y de las estrategias actuales de manejo y de mostrar más apoyo por los refugios de gatos abandonados, la adopción y de la recaudación de fondos comunitaria que quienes no son dueños, no son religiosos y son hombres (p < 0.05). La propiedad de gatos libres y el abandono ocurrieron menos con los dueños con más conocimiento sobre la biodiversidad y las especies invasoras que con los respondientes con menos conocimiento sobre estos temas (p < 0.05). Recomendamos que los aficionados a los gatos y los conservacionistas de la fauna participen en las iniciativas comunitarias; por ejemplo, campañas para mantener a los gatos dentro de casa. Nuestro estudio proporciona un marco sustancialmente útil para otras regiones en donde los gatos libres se encuentran en rápida expansión.

Top-Down Effect of Arthropod Predator Chinese Mitten Crab on Freshwater Nutrient Cycling.

Aquatic litter decomposition is highly dependent on contributions and interactions at different trophic levels. The invasion of alien aquatic organisms like the channeled apple snail (Pomacea canaliculata) might lead to changes in the decomposition process through new species interactions in the invaded wetland. However, it is not clear how aquatic macroinvertebrate predators like the Chinese mitten crab (Eriocheir sinensis) will affect the nutrient cycle in freshwater ecosystems in the face of new benthic invasion. We used the litter bag method to explore the top-down effect of crabs on the freshwater nutrient cycle with the help of soil zymography (a technology previously used in terrestrial ecosystems). The results showed significant feeding effects of crabs and snails on lotus leaf litter and cotton strips. Crabs significantly inhibited the intake of lotus litter and cotton strips and the ability to transform the environment of snails by predation. Crabs promoted the decomposition of various litter substrates by affecting the microbial community structure in the sediment. These results suggest that arthropod predators increase the complexity of detrital food webs through direct and indirect interactions, and consequently have an important impact on the material cycle and stability of freshwater ecosystems. This top-down effect makes macrobenthos play a key role in the biological control and engineering construction of freshwater ecosystems.

Using a behavior random permutation model to identify displacement grooming in ungulates.

Behavior affects an individual's life in all aspects, e.g., enhancing fitness, leveraging predation risk, and reducing competition with conspecifics. However, the sequential distribution of behaviors received less attention and is unclear what the function of displacement behavior is. Displacement activities can be found in vertebrate species but there is no formal method to determine whether a behavior is expressed as a displaced or normal activity. Analyzing the sequential distributions of behaviors in a natural setting may allow researchers to identify unexpected distributions as a possible signature of displacement activities. In this study, we used a behavior random permutation model to detect the presence of a displacement activity in the Tibetan antelope Pantholops hodgsonii and the Tibetan gazelle Procapra picticaudata. The results showed that grooming in both ungulates tended to be accompanied with vigilance, and the frequency of grooming after vigilance was significantly higher than before vigilance. A significant positive correlation between the scan rate and grooming rate in the 2 ungulates was obtained. We suggest that grooming could sometimes be expressed as a displacement activity in ungulates. In addition to providing a general method for further research on displacement activities in a variety of animal species, this study sheds light on the importance of a spectral analysis of sequential distribution of animal behaviors. Behavior random permutation models can be used to explore the relevance between any 2 behaviors in a specific sequence, especially to identify a myriad of unexpected behaviors relative to their normal context of occurrence.

Microplastics are transferred by soil fauna and regulate soil function as material carriers.

The ecotoxicological effects of microplastics, a new and widespread ecosystem pollutant, have been extensively reported. However, it remains unclear whether soil fauna transfer microplastics and whether migration behaviours influence subsequent ecological functions in terrestrial ecosystems. We investigated the transfer patterns of microplastics and their adsorbed substances by soil animals (the springtail, Folsomia candida) and the effect of the transfer on the decomposition of soil organic matter through a standardized cotton strip assay. The results showed that springtails had a strong ability to transfer microplastics into the soil. The adsorbed nutrient (nitrogen; N), pollutant (cadmium; Cd), and green fluorescent Escherichia coli (GFP-E. coli) were also transferred with the microplastics. In addition, cotton strip decomposition was accelerated when the microplastics adsorbed N, but the adsorption of Cd decreased decomposition. These ecological effects were particularly strong for small microplastics. Microplastic transfer regulated soil bacterial communities, promoting the growth of Ascomycota fungi and inhibiting that of Basidiomycota, leading to cotton strip decomposition. Thus, microplastic pollution may occur at one site, but microplastics can be transferred anywhere in terrestrial ecosystems by soil animals and adsorb other substances, including nutrients and pollutants, that affect ecosystem function. Therefore, more studies on the migration behaviour of microplastics are necessary.

Performance on inhibitory tasks does not relate to handedness in several small groups of Callitrichids.

Brain lateralization, a trait ubiquitous in vertebrates and invertebrates, refers to structural differences between the left and right sides of the brain or to the left and right sides controlling different functions or processing information in different ways. Many studies have looked into the advantages of lateralized brains and discovered that cerebral lateralization confers a fitness advantage. Enhancing cognitive ability has been proposed as one of the potential benefits of the lateralized brain, however, this has not been widely validated. In this study, we investigated the handedness of 34 subjects from four groups of Callitrichids, as well as their performance in two inhibitory control tasks (the revised A-not-B task and the cylinder task). The subjects had strong individual hand preferences, and only a few zoo-born individuals were ambidextrous. Sex and generation influence the strength of hand preference. In the cylinder task, the subjects showed differences between groups, and the performance of the second-generation was better than that of the first-generation. We found that neither the strength of hand preferences (ABS-HI) or direction of hand preferences (HI) was linked with success on the two inhibitory tasks. That is, we were unable to support the enhanced cognitive function hypothesis. We believe that individual ontogeny and the type of cognitive task have an impact on the support of this hypothesis. The advantages of lateralized brain may be reflected in tests that require multiple cognitive abilities.

Grazing Effects of Soil Fauna on White-Rot Fungi: Biomass, Enzyme Production and Litter Decomposition Ability.

Soil invertebrates and microorganisms are two major drivers of litter decomposition. Even though the importance of invertebrates and microorganisms in biogeochemical soil cycles and soil food webs has been studied, the effects of invertebrates on fungi are not well understood compared to other organisms. In this work, we investigated the effects of soil invertebrates on fungi as a factor that cannot be ignored in the study of nutrient cycling. The result showed the grazing of isopods on white-rot fungi was transitive and persistent. The grazed fungi appeared "compensatory" growing. The biomass of fungi increased after grazing. The activities of enzymes associated with nutrient cycling were increased under grazing. The zymography images showed the enzyme hotspots and activities also increased significantly in the grazing area. The results suggest that invertebrate grazing can significantly increase the fungal biomass and enzyme activity, accelerating litter decomposition in the unreached grazer area. The grazing effects of invertebrate plays an important role in promoting the nutrient cycling of the forest ecosystem. We believe that this study will be a good reference related to showing the relationship between soil invertebrates, fungi and soil biogeochemical cycles.

Socio-ecological correlates of neophobia in corvids.

Behavioral responses to novelty, including fear and subsequent avoidance of novel stimuli, i.e., neophobia, determine how animals interact with their environment. Neophobia aids in navigating risk and impacts on adaptability and survival. There is variation within and between individuals and species; however, lack of large-scale, comparative studies critically limits investigation of the socio-ecological drivers of neophobia. In this study, we tested responses to novel objects and food (alongside familiar food) versus a baseline (familiar food alone) in 10 corvid species (241 subjects) across 10 labs worldwide. There were species differences in the latency to touch familiar food in the novel object and novel food conditions relative to the baseline. Four of seven socio-ecological factors influenced object neophobia: (1) use of urban habitat (versus not), (2) territorial pair versus family group sociality, (3) large versus small maximum flock size, and (4) moderate versus specialized caching (whereas range, hunting live animals, and genus did not), while only maximum flock size influenced food neophobia. We found that, overall, individuals were temporally and contextually repeatable (i.e., consistent) in their novelty responses in all conditions, indicating neophobia is a stable behavioral trait. With this study, we have established a network of corvid researchers, demonstrating potential for further collaboration to explore the evolution of cognition in corvids and other bird species. These novel findings enable us, for the first time in corvids, to identify the socio-ecological correlates of neophobia and grant insight into specific elements that drive higher neophobic responses in this avian family group. VIDEO ABSTRACT.

Effect of Tank Size on Zebrafish Behavior and Physiology.

Environmental conditions strongly affect experimental animals. As a model organism, zebrafish has become important in life science studies. However, the potential effect of living environment on their behavior and physiology is often overlooked. This work aimed to determine whether tank size affects zebrafish behavior and physiology. Tests on shelter leaving, shelter seeking, shoaling, stamina, and pepsin and cortisol levels were conducted. Results showed that zebrafish behavior is easily affected by changes on the tank size. Fish that lived in small tanks behaved less boldly, had poor stamina, and spent much time on movement. Sex differences in behavior were only evident in the shelter seeking tests. Tank size had no effect on pepsin and cortisol, but cortisol concentrations in males were lower than those in females. This study suggests that zebrafish behavior is easily influenced by their living environment, and future related studies should consider their living space.

Azure-winged magpies fail to understand the principle of mirror imaging.

Mirror self-recognition (MSR) is considered a crucial step in the emergence of self-cognition. The MSR paradigm has become a standard method for evaluating self-cognition in several species. For example, Eurasian magpies and Indian house crows have passed the mark test for self-cognition, whereas efforts to find MSR in other corvid species have failed. However, no literature has conducted MSR tests on azure-winged magpies, a species of corvids. Therefore, the current research aimed to investigate the MSR behaviours of azure-winged magpies upon looking into a mirror for the first time. The study included four tests: (1) mirror preference and standardised mirror exploration, (2) single vertical mirror test, (3) mark test and (4) mirror-triggered search test. The azure-winged magpies displayed immense curiosity towards the mirror and their images in the mirror in Test 1&2. In the subsequent mark tests, they failed to recognise themselves in the mirror and regarded their images as conspecifics. Behaviour analysis showed no significant difference between marked and unmarked behaviours. Finally they seemed to infer the presence of bait from the image in the mirror, but were found to fail to understand that the location of the bait in the mirror was the same as that in the real world. For a better insight into the MSR behaviour of azure-winged magpies, research studies involving prolonged mirror exposure and training are recommended.

Azure-winged magpies solve string-pulling tasks by partial understanding of the physical cognition.

String-pulling is one of the most widely used paradigms in animal cognition research. We investigated how azure-winged magpies Cyanopica cyanus solve multiple-string problems that they have never encountered before. In Experiment 1, the strings were arranged in parallel, slanted, or crossed to investigate what rules azure-winged magpies use to solve multiple spatial relations of strings. Experiment 2 assessed whether the subjects understood the connection between the string and the bait while taking advantage of broken strings. In Experiment 3, the subjects were confronted with strings of different lengths attached to rewards in order to explore whether the string length, as a proxy for the pulling efficiency or reward distance, was crucial for the birds' choice of which string to pull. Generally, the birds were successful in tasks where the reward was close to the correct string's end, and they relied on a "proximity rule" in most cases. The results showed that azure-winged magpies had a partial understanding of the physical principles underlying the string-pulling but were stumped by complex spatial relations. They likely relied on simple strategies such as the proximity rule to solve the tasks. The effects of individual difference and experiential learning on string-pulling performance are also discussed.

Puppet resting behavior in the Tibetan antelope (Pantholops hodgsonii).

Rest contributes a large part of animals' daily life, and animals usually rest in two ways, standing or in recumbence. Small or medium sized ungulates bed to rest in most cases, and standing rest is very rare and hardly seen. Here we described a standing rest behavior of Tibetan antelopes (Pantholops hodgsonii) living on the Tibet Plateau which has not been reported before. We named the standing rest behavior Puppet behavior, since the antelope stand still for a certain time. Of the 304 individuals observed, 48.3% (98/203) of adult and sub-adult males expressed the Puppet behavior, whereas only 6.3% (6/96) of females did, indicating an obvious sexual difference. Puppet behavior occurred more frequently at noon and in the afternoon on sunny and cloudy days, meaning that daytime and weather were both influential factors. Puppet behavior was usually accompanied with rumination and sometimes ended with leg-shaking. Our results suggest that Puppet behavior may be an adaptive form of rest, which may serve a thermoregulatory and anti-predation function, and may be simpler and safer than recumbent rest.

Functional Analysis of a c-di-AMP-specific Phosphodiesterase MsPDE from Mycobacterium smegmatis.

Cyclic di­AMP (c-di-AMP) is a second signaling molecule involved in the regulation of bacterial physiological processes and interaction between pathogen and host. However, the regulatory network mediated by c-di-AMP in Mycobacterium remains obscure. In M. smegmatis, a diadenylate cyclase (DAC) was reported recently, but there is still no investigation on c-di-AMP phosphodiesterase (PDE). Here, we provide a systematic study on signaling mechanism of c-di-AMP PDE in M. smegmatis. Based on our enzymatic analysis, MsPDE (MSMEG_2630), which contained a DHH-DHHA1 domain, displayed a 200-fold higher hydrolytic efficiency (kcat /Km ) to c-di-AMP than to c-di-GMP. MsPDE was capable of converting c-di-AMP to pApA and AMP, and hydrolyzing pApA to AMP. Site-directed mutations in DHH and DHHA1 revealed that DHH domain was critical for the phosphodiesterase activity. To explore the regulatory role of c-di-AMP in vivo, we constructed the mspde mutant (Δmspde) and found that deficiency of MsPDE significantly enhanced intracellular C12-C20 fatty acid accumulation. Deficiency of DAC in many bacteria results in cell death. However, we acquired the M. smegmatis strain with DAC gene disrupted (ΔmsdisA) by homologous recombination approach. Deletion of msdisA reduced bacterial C12-C20 fatty acids production but scarcely affected bacterial survival. We also provided evidences that superfluous c-di-AMP in M. smegmatis could lead to abnormal colonial morphology. Collectively, our results indicate that MsPDE is a functional c-di-AMP-specific phosphodiesterase both in vitro and in vivo. Our study also expands the regulatory network mediated by c-di-AMP in M. smegmatis.

Highly efficient enzymatic preparation of c-di-AMP using the diadenylate cyclase DisA from Bacillus thuringiensis.

Cyclic 3',5'-diadenosine monophosphate (c-di-AMP) is a newly recognized bacterial nucleotide second messenger molecule. In addition, it has been shown to be a potential vaccine adjuvant. Although multiple methods are available for c-di-AMP synthesis, the yields are low and the purification procedures are laborious. Here, we report an enzymatic method for more efficient and economical c-di-AMP synthesis using a diadenylate cyclase DisA from Bacillus thuringiensis BMB 171 (btDisA). After overexpression and purification of btDisA, the enzyme-catalyzed reaction conditions were further investigated. Under the optimum conditions, in which 100mM CHES (pH 9.5) containing 2µM btDisA, 10mM ATP, and 10mM MgCl2 was incubated at 50°C for 4h, a high conversion rate of c-di-AMP was obtained. Coupling this process with HPLC purification and lyophilization yielded 100mg of highly pure c-di-AMP that was harvested in white powder form from a 50mL enzyme-catalyzed reaction system. The protocol is not only directly applicable for preparing abundant amounts of c-di-AMP for extensive biochemical and immunological use, but can also be scaled up to meet the requirements for medical applications.