Functional and phylogenetic relationships link predators to plant diversity via trophic and non-trophic pathways.

Human-induced biodiversity loss negatively affects ecosystem function, but the interactive effects of biodiversity change across trophic levels remain insufficiently understood. We sampled arboreal spiders and lepidopteran larvae across seasons in 2 years in a subtropical tree diversity experiment, and then disentangled the links between tree diversity and arthropod predator diversity by deconstructing the pathways among multiple components of diversity (taxonomic, phylogenetic and functional) with structural equation models. We found that herbivores were major mediators of plant species richness effects on abundance, species richness, functional and phylogenetic diversity of predators, while phylogenetic, functional and structural diversity of trees were also important mediators of this process. However, the strength and direction differed between functional, structural and phylogenetic diversity effects, indicating different underlying mechanisms for predator community assembly. Abundance and multiple diversity components of predators were consistently affected by tree functional diversity, indicating that the variation in structure and environment caused by plant functional composition might play key roles in predator community assembly. Our study highlights the importance of an integrated approach based on multiple biodiversity components in understanding the consequences of biodiversity loss in multitrophic communities.

Tree dissimilarity determines multi-dimensional beta-diversity of herbivores and carnivores via bottom-up effects.

Global biodiversity decline and its cascading effects through trophic interactions pose a severe threat to human society. Establishing the impacts of biodiversity decline requires a more thorough understanding of multi-trophic interactions and, more specifically, the effects that loss of diversity in primary producers has on multi-trophic community assembly. Within a synthetic conceptual framework for multi-trophic beta-diversity, we tested a series of hypotheses on neutral and niche-based bottom-up processes in assembling herbivore and carnivore communities in a subtropical forest using linear models, hieratical variance partitioning based on linear mixed-effects models (LMMs) and simulation. We found that the observed taxonomic, phylogenetic and functional beta-diversity of both herbivorous caterpillars and carnivorous spiders were significantly and positively related to tree dissimilarity. Linear models and variance partitioning for LMMs jointly suggested that as a result of bottom-up effects, producer dissimilarities were predominant in structuring consumer dissimilarity, the strength of which highly depended on the trophic dependencies on producers, the diversity facet examined, and data quality. Importantly, linear models for standardized beta-diversities against producer dissimilarities implied a transition between niche-based processes such as environmental filtering and competitive exclusion, which supports the role of bottom-up effect in determining consumer community assembly. These findings enrich our mechanistic understanding of the 'Diversity Begets Diversity' hypothesis and the complexity of higher-trophic community assembly, which is fundamental for sustainable biodiversity conservation and ecosystem management.

Tree communities and functional traits determine herbivore compositional turnover.

There are many factors known to drive species turnover, although the mechanisms by which these operate are less clear. Based on comprehensive datasets from the largest tree diversity experiment worldwide (BEF-China), we used shared herbivore species (zeta diversity) and multi-site generalized dissimilarity modelling to investigate the patterns and determinants of species turnover of Lepidoptera herbivores among study plots across a gradient in tree species richness. We found that zeta diversity declined sharply with an increasing number of study plots, with complete changes in caterpillar species composition observed even at the fine spatial scale of our study. Plant community characteristics rather than abiotic factors were found to play key roles in driving caterpillar compositional turnover, although these effects varied with an increasing number of study plots considered, due to the varying contributions of rare and common species to compositional turnover. Our study reveals details of the impact of phylogeny- and trait-mediated processes of trees on herbivore compositional turnover, which has implications for forest management and conservation and shows potential avenues for maintenance of heterogeneity in herbivore communities.

Host functional and phylogenetic composition rather than host diversity structure plant-herbivore networks.

Declining plant diversity alters ecological networks, such as plant-herbivore interactions. However, our knowledge of the potential mechanisms underlying effects of plant species loss on plant-herbivore network structure is still limited. We used DNA barcoding to identify herbivore-host plant associations along declining levels of tree diversity in a large-scale, subtropical biodiversity experiment. We tested for effects of tree species richness, host functional and phylogenetic diversity, and host functional (leaf trait) and phylogenetic composition on species, phylogenetic and network composition of herbivore communities. We found that phylogenetic host composition and related palatability/defence traits but not tree species richness significantly affected herbivore communities and interaction network complexity at both the species and community levels. Our study indicates that evolutionary dependencies and functional traits of host plants determine the composition of higher trophic levels and corresponding interaction networks in species-rich ecosystems. Our findings highlight that characteristics of the species lost have effects on ecosystem structure and functioning across trophic levels that cannot be predicted from mere reductions in species richness.

Sub-pm linewidth nanosecond Nd:GYSGG laser at 1336.6 nm.

We demonstrate a sub-pm linewidth acousto-optic (AO) Q-switched nanosecond Nd:GYSGG ring laser at 1336.6 nm side-pumped by 808-nm quasi-continuous wave (QCW) diode lasers for the first time. With incident pulse energy of 4.23 J at 10 Hz, a maximum output macropulse energy of 36.7 mJ at 1336.6 nm with linewidth of less than 0.85 pm and a micropulse width of 300 ns was obtained at a repetition rate of 80 Hz, corresponding to an average micropulse peak power of 15.3 kW. The M² factors were measured to be 1.42 and 1.10 in x and y directions, respectively. It can be tuned from 1336.576 to 1336.652 nm with a tuning resolution of 1 pm. The 1336.632 nm can be converted to deep ultraviolet (DUV) laser at 167.079 nm through its eighth harmonics, which is very useful for the ²7Al⁺ optical frequency standard.

Plant diversity enhances ecosystem multifunctionality via multitrophic diversity.

Ecosystem functioning depends on biodiversity at multiple trophic levels, yet relationships between multitrophic diversity and ecosystem multifunctionality have been poorly explored, with studies often focusing on individual trophic levels and functions and on specific ecosystem types. Here, we show that plant diversity can affect ecosystem functioning both directly and by affecting other trophic levels. Using data on 13 trophic groups and 13 ecosystem functions from two large biodiversity experiments-one representing temperate grasslands and the other subtropical forests-we found that plant diversity increases multifunctionality through elevated multitrophic diversity. Across both experiments, the association between multitrophic diversity and multifunctionality was stronger than the relationship between the diversity of individual trophic groups and multifunctionality. Our results also suggest that the role of multitrophic diversity is greater in forests than in grasslands. These findings imply that, to promote sustained ecosystem multifunctionality, conservation planning must consider the diversity of both plants and higher trophic levels.

[Recent advances in the techniques of protein-protein interaction study].

Protein-protein interactions play key roles in the development of organisms and the response to biotic and abiotic stresses. Several wet-lab methods have been developed to study this challenging area,including yeast two-hybrid system, tandem affinity purification, Co-immunoprecipitation, GST Pull-down, bimolecular fluorescence complementation, fluorescence resonance energy transfer and surface plasmon resonance analysis. In this review, we discuss theoretical principles and relative advantages and disvantages of these techniques,with an emphasis on recent advances to compensate for limitations.

Multitrophic arthropod diversity mediates tree diversity effects on primary productivity.

Forests sustain 80% of terrestrial biodiversity and provide essential ecosystem services. Biodiversity experiments have demonstrated that plant diversity correlates with both primary productivity and higher trophic diversity. However, whether higher trophic diversity can mediate the effects of plant diversity on productivity remains unclear. Here, using 5 years of data on aboveground herbivorous, predatory and parasitoid arthropods along with tree growth data within a large-scale forest biodiversity experiment in southeast China, we provide evidence of multidirectional enhancement among the diversity of trees and higher trophic groups and tree productivity. We show that the effects of experimentally increased tree species richness were consistently positive for species richness and abundance of herbivores, predators and parasitoids. Richness effects decreased as trophic levels increased for species richness and abundance of all trophic groups. Multitrophic species richness and abundance of arthropods were important mediators of plant diversity effects on tree productivity, suggesting that optimizing forest management for increased carbon capture can be more effective when the diversity of higher trophic groups is promoted in concert with that of trees.

N-acetylcysteine ameliorates erectile dysfunction in rats with hyperlipidemia by inhibiting oxidative stress and corpus cavernosum smooth muscle cells phenotypic modulation.

Hyperlipidemia is a major risk factor for erectile dysfunction (ED). Oxidative stress and phenotypic modulation of corpus cavernosum smooth muscle cells (CCSMCs) are the key pathological factors of ED. N-acetylcysteine (NAC) can inhibit oxidative stress; however, whether NAC can alleviate pathological variations in the corpus cavernosum and promote erectile function recovery in hyperlipidemic rats remains unclear. A hyperlipidemia model was established using 27 eight-week-old male Sprague-Dawley (SD) rats fed a high-fat and high-cholesterol diet (hyperlipidemic rats, HR). In addition, 9 male SD rats were fed a normal diet to serve as controls (NC). HR rats were divided into three groups: HR, HR+normal saline (NS), and HR+NAC (n = 9 for each group; NS or NAC intraperitoneal injections were administered daily for 16 weeks). Subsequently, the lipid profiles, erectile function, oxidative stress, phenotypic modulation markers of CCSMCs, and tissue histology were analyzed. The experimental results revealed that erectile function was significantly impaired in the HR and HR + NS groups, but enhanced in the HR + NAC group. Abnormal lipid levels, over-activated oxidative stress, and multi-organ lesions observed in the HR and HR + NS groups were improved in the HR + NAC group. Moreover, the HR group showed significant phenotypic modulation of CCSMCs, which was also inhibited by NAC treatment. This report focuses on the therapeutic effect of NAC in restoring erectile function using a hyperlipidemic rat model by preventing CCSMC phenotypic modulation and attenuating oxidative stress.