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Diglyphus wani (Hymenoptera: Eulophidae) is a dominant parasitoid that attacks agromyzid leafminers. Two reproductive types occur in D. wani: arrhenotoky (in which virgin females produce only male offspring; and virgin females mate with males to produce bisexual offspring) and thelytoky (in which virgin females produce female offspring). As a potential biological control agent, exploring the differences in the relevant biological parameters of both strains is necessary. In this study, comparisons between the two strains of D. wani were performed by evaluating the life table and host-killing rate. The thelytokous strain exhibited significantly better life table parameters than its arrhenotokous counterpart. Higher values for the intrinsic rate of increase, finite rate of increase, net reproductive rate, and fecundity were found in the thelytokous strain. The thelytokous strain also performed better than the arrhenotokous strain in terms of net parasitism, host-feeding, host-stinging, and total host-killing rates. Thus, populations of the thelytokous strain could grow fast and kill more hosts. In conclusion, the thelytokous strain of D. wani may be the more promising biological agent against agromyzid leafminers compared to its arrhenotokous counterpart. Also, since the thelytokous strain of D. wani is only known to produce females, it should be given priority in future biocontrol applications owing to the cost savings of breeding only females.

Leaf-mining flies (Diptera: Agromyzidae) are a diverse family of small-bodied insects that feed on living plant tissues as larvae. Various species in this family are considered globally invasive and have caused great agricultural economic losses. In China, economically important vegetable crops have been seriously damaged by these pest insects, especially by species of the genus Liriomyza. However, these species are difficult to differentiate because of their morphological similarities, and the Chinese fauna remains poorly known. To explore the relevant pest species in China and their phylogeny, agromyzid leafminers were collected from 2016 to 2019, and identified based on morphological characteristics and DNA barcodes. In total, 27 species from five genera of Agromyzidae were sampled and identified, including 16 species of Liriomyza. Both mitochondrial and nuclear genes were used to reconstruct their phylogenetic relationships and estimate the divergence time. Highly congruent and well-supported phylogenetic trees were obtained using the Bayesian inference and maximum-likelihood methods. This analysis revealed two main clades in Liriomyza, and clade 2 was inferred to have diverged from clade 1 approximately 27.40 million years ago (95% highest posterior density: 23.03–31.52 million years ago) in the Oligocene. Differences were observed in the distribution patterns and host associations between the Liriomyza clades. Clade 2 species are distributed in cool, high-latitude environments, suggesting that they may have evolved into a cool-adapted lineage.

Invasive alien ants (IAAs) are among the most aggressive, competitive, and widespread invasive alien species (IAS) worldwide. Wasmannia auropunctata, the greatest IAAs threat in the Pacific region and listed in “100 of the world’s worst IAS”, has established itself in many countries and on islands worldwide. Wild populations of W. auropunctata were recently reported in southeastern China, representing a tremendous potential threat to China’s agricultural, economic, environmental, public health, and social well-being. Estimating the potential geographical distribution (PGD) of W. auropunctata in China can illustrate areas that may potentially face invasion risk. Therefore, based on the global distribution records of W. auropunctata and bioclimatic variables, we predicted the geographical distribution pattern of W. auropunctata in China under the effects of climate change using an ensemble model (EM). Our findings showed that artificial neural network (ANN), flexible discriminant analysis (FDA), gradient boosting model (GBM), Random Forest (RF) were more accurate than categorical regression tree analysis (CTA), generalized linear model (GLM), maximum entropy model (MaxEnt) and surface distance envelope (SRE). The mean TSS values of ANN, FDA, GBM, and RF were 0.820, 0.810, 0.843, and 0.857, respectively, and the mean AUC values were 0.946, 0.954, 0.968, and 0.979, respectively. The mean TSS and AUC values of EM were 0.882 and 0.972, respectively, indicating that the prediction results with EM were more reliable than those with the single model. The PGD of W. auropunctata in China is mainly located in southern China under current and future climate change. Under climate change, the PGD of W. auropunctata in China will expand to higher-latitude areas. The annual temperature range (bio7) and mean temperature of the warmest quarter (bio10) were the most significant variables affecting the PGD of W. auropunctata in China. The PGD of W. auropunctata in China was mainly attributed to temperature variables, such as the annual temperature range (bio7) and the mean temperature of the warmest quarter (bio10). The populations of W. auropunctata in southern China have broad potential invasion areas. Developing strategies for the early warning, monitoring, prevention, and control of W. auropunctata in southern China requires more attention.

Global food security is threatened by the impacts of the spread of crop pests and changes in the complex interactions between crops and pests under climate change. Schrankia costaestrigalis is a newly-reported potato pest in southern China. Early-warning monitoring of this insect pest could protect domestic agriculture as it has already caused regional yield reduction and/or quality decline in potato production. Our research aimed to confirm the potential geographical distributions (PGDs) of S. costaestrigalis in China under different climate scenarios using an optimal MaxEnt model, and to provide baseline data for preventing agricultural damage by S. costaestrigalis. Our findings indicated that the accuracy of the optimal MaxEnt model was better than the default-setting model, and the minimum temperature of the coldest month, precipitation of the driest month, precipitation of the coldest quarter, and the human influence index were the variables significantly affecting the PGDs of S. costaestrigalis. The highly- and moderately-suitable habitats of S. costaestrigalis were mainly located in eastern and southern China. The PGDs of S. costaestrigalis in China will decrease under climate change. The conversion of the highly- to moderately-suitable habitat will also be significant under climate change. The centroid of the suitable habitat area of S. costaestrigalis under the current climate showed a general tendency to move northeast and to the middle-high latitudes in the 2030s. The agricultural practice of plastic film mulching in potato fields will provide a favorable microclimate for S. costaestrigalis in the suitable areas. More attention should be paid to the early warning and monitoring of S. costaestrigalis in order to prevent its further spread in the main areas in China’s winter potato planting regions.

Temperature, as a critical abiotic factor, might influence the effectiveness of biological control by parasitoids in host-parasitoid systems. In this study, Neochrysocharis formosa (Westwood), a larval endoparasitoid, is used to investigate the efficacy of biological control on a vegetable agriculture pest, Liriomyza sativae Blanchard, reared on kidney bean (Phaseolus vulgaris L.), at four constant temperatures (26, 29, 32, and 35°C) under laboratory conditions. Our results show that high temperatures (29, 32, and 35°C) do not significantly affect lifetime host-killing events of female adults by increased daily host-killing events compared to temperature of 26°C, although their lifespans decrease with an increase in temperatures. Each life-history trait of female adults (lifespan, parasitism, stinging, or non-reproductive host-killing events) present a linear relation with temperatures and host-feeding events, respectively. Our findings contribute to a better understanding of biocontrol efficacy of parasitoid N. formosa against agromyzid leafminers at high-temperature seasons or environments.

Diglyphus species are ecologically and economically important on agromyzid leafminers. In 2018, a thelytokous species, Diglyphus wani Liu, Zhu & Yefremova, was firstly reported and described. Subsequently, the arrhenotokous D. wani were discovered in Yunnan and Guizhou Provinces of China. We compared the morphological characteristics of thelytokous and arrhenotokous strains. However, the females of two strains had a strongly similar morphology and showed subtle differences in fore- and hind-wings. The difference was that forewing of arrhenotokous female was with denser setae overall, showing that costal cell with 2 ~ 4 rows of setae on dorsal surface and the setae of basal cell with 15 ~ 21 hairs and forewing of thelytokous female was with two rows of setae on dorsal surface and basal cell with 10 ~ 15 hairs generally. The setation beneath the marginal vein of the hind-wing of arrhenotokous female is denser than the same area of thelytokous female. To explore the genetic divergence between thelytokous and arrhenotokous strains of D. wani, the mitochondrial and nuclear gene were applied and sequenced. The polygenic analyses revealed that two strains can be distinguished by COI, ITS1 and ITS2. The mean sequence divergence between the two strains was 0.052, 0.010 and 0.007, respectively. Nevertheless, the 28S gene was unfeasible due to its containing a sharing haplotype between different strains. The two strains of D. wani are dominant parasitoids against agromyzid leafminers and such effective discernible foundation provides future in-depth studies on biological characteristics, along with insight into field application of two strains of D. wani.

Characterization of spatiotemporal variation of the stable isotopes δ18O and δD in surface water is essential to trace the water cycle, indicate moisture sources, and reconstruct paleoaltimetry. In this study, river water, rainwater, and groundwater samples were collected in the Yarlung Tsangpo River (YTR) Basin before (BM) and after the monsoon precipitation (AM) to investigate the δ18O and δD spatiotemporal variation of natural water. Most of the river waters are distributed along GMWL and the line of d-excess = 10‰, indicating that they are mainly originated from precipitation. Temporally, the δ18O and δD of river water are higher in BM series (SWL: δD = 10.26δ18O+43.01, R2 = 0.98) than AM series (SWL: δD = 9.10δ18O + 26.73, R2 = 0.82). Spatially, the isotopic compositions of tributaries increase gradually from west to east (BM: δ18O = 0.65Lon (°)-73.89, R2 = 0.79; AM: δ18O = 0.45Lon (°)-57.81, R2 = 0.70) and from high altitude to low (BM: δ18O = −0.0025Alt(m)-73.89, R2 = 0.66; AM: δ18O = −0.0018Alt(m)-10.57, R2 = 0.58), which conforms to the “continent effect” and “altitude effect” of precipitation. In the lower reaches of the mainstream, rainwater is the main source, so the variations of δ18O and δD are normally elevated with the flow direction. Anomalously, in the middle reaches, the δ18Omainstream and δDmainstream values firstly increase and then decrease. From the Saga to Lhaze section, the higher positive values of δ18Omainstream are mainly caused by groundwater afflux, which has high δ18O and low d-excess values. The δ18Omainstream decrease from the Lhaze to Qushui section is attributed to the combined action of the import of depleted 18O and D groundwater and tributaries. Therefore, because of the recharge of groundwater with markedly different δ18O and δD values, the mainstream no longer simply inherits the isotopic composition from precipitation. These results suggest that in the YTR Basin, if the δ18O value of surface water is used to trace moisture sources or reconstruct the paleoaltimetry, it is necessary to rule out the influence from groundwater.

Abstract The whitefly Bemisia tabaci is a phloem-feeding pest that lives predominantly on herbaceous species and causes serious damage to hosts. Whitefly saliva is thought to contain proteins that modulate plant defences and facilitate feeding. A predicted secreted protein, laccase 1 (LAC1), was found in the salivary gland transcriptome of B. tabaci and might be existed in the watery saliva of B. tabaci. As LAC1 has a potential role in detoxification of secondary plant compounds in insects, we speculated that it may participate in the insect’s response to plant defences. Here, we cloned the complete cDNA of LAC1 and found that (1) LAC1 was highly expressed in the salivary gland (SG) and midgut; (2) LAC1 transcript level in head (containing SG) was 2.1 times higher in plant-fed than in diet-fed whiteflies and 1.6 times higher in the head and 23.8 times higher in the midgut of whiteflies that fed on jasmonic acid (JA)-sprayed plants than on control plants; and (3) silencing LAC1 decreased the survival rate of plant-fed whiteflies but had a marginal effect on whiteflies raised on an artificial diet. These results indicate that LAC1 enables whiteflies to overcome the chemical defences of host plants and might act as an effector in saliva.

Frequent droughts in a warming climate tend to induce the degeneration of vegetation. Quantifying the response of vegetation to variations in drought events is therefore crucial for evaluating the potential impacts of climate change on ecosystems. In this study, the standardized precipitation index (SPI) was calculated using the precipitation data sourced from the China Meteorological Forcing Dataset (CMFD), and then the drought events in southern Tibet from 1982 to 2015 were identified based on the SPI index. The results showed that the frequency, severity, and intensity of drought events in southern Tibet decreased from 1982 to 2015, and the highest frequency of drought was found between 1993 and 2000. To evaluate the impact of drought events on vegetation, the vegetation characteristic indexes were developed based on the normalized difference vegetation index (NDVI) and the drought characteristics. The assessment of two drought events showed that the alpine grasslands and alpine meadows had high vegetation vulnerability (AI). The assessment of multiple drought events showed that responses of vegetation to drought were spatially heterogeneous, and the total explain rate of environmental factors to the variations in AI accounted for 40%. Among the many environmental factors investigated, the AI were higher at middle altitudes (2000–3000 m) than low altitudes (

The whitefly Bemisia tabaci is a species complex, of which two invasive species, called MEAM1 and MED whiteflies, have invaded many parts of the world in the past 30 years and replaced native whitefly populations in many regions of invasions including many areas in China. One of the possible reasons for the invasion is that MEAM1 and MED whiteflies are more fecund than the native species. However, factors that affect reproduction and the molecular mechanism of vitellogenesis among various B. tabaci cryptic species are not clearly known. In this study, cDNAs of vitellogenin (Vg) genes were sequenced from native B. tabaci Asia II 1 and invasive B. tabaci MED in China. The deduced amino acid sequences were 2 182 residues in Asia II 1 and 2 217 residues in MED. Compared to the Vg gene cDNA sequence of Asia II 1 species, the Vg gene in MED could be cleaved at least into four subunits, with deduced molecular weight of 50, 90, 150 and 190 kDa, respectively. However, only two different subunits were cleaved between residues 459 and 460 in the Asia II 1. In addition, more than two serine-rich stretches located in both the N-terminal and the C-terminal region in invasive species. More GHN domains were revealed only in the N-terminal region of B. tabaci MED. Vg gene expression pattern was characterized using quantitative real-time (qRT)-PCR to compare the dynamic of vitellogenin gene mRNA level. Vg gene transcription reached the peak level at 13 d after eclosion in B. tabaci Asia II 1, 3 d later than that in MED and another invasive species of the B. tabaci complex MEAM1. We assumed that the present difference of Vg gene expression pattern is due to the different regulation pattern of vitellogenesis among species of the B. tabaci complex. These results provide useful information to reveal the mechanisms of reproduction in whitefly species complex.

Background: Bemisia tabaci species (B. tabaci), or whiteflies, are the world’s most devastating insect pests. They cause billions of dollars (US) of damage each year, and are leaving farmers in the developing world food insecure. Currently, all publically available transcriptome data for B. tabaci are generated from pooled samples, which can lead to high heterozygosity and skewed representation of the genetic diversity. The ability to extract enough RNA from a single whitefly has remained elusive due to their small size and technological limitations. Methods: In this study, we optimised a single whitefly RNA extraction procedure, and sequenced the transcriptome of four individual adult Sub-Saharan Africa 1 (SSA1) B. tabaci. Transcriptome sequencing resulted in 39-42 million raw reads. De novo assembly of trimmed reads yielded between 65,000-162,000 Contigs across B. tabaci transcriptomes. Results: Bayesian phylogenetic analysis of mitochondrion cytochrome I oxidase (mtCOI) grouped the four whiteflies within the SSA1 clade. BLASTn searches on the four transcriptomes identified five endosymbionts; the primary endosymbiont Portiera aleyrodidarum and four secondary endosymbionts: Arsenophonus, Wolbachia, Rickettsia, and Cardinium spp. that were predominant across all four SSA1 B. tabaci samples with prevalence levels of between 54.1 to 75%. Amino acid alignments of the NusG gene of P. aleyrodidarum for the SSA1 B. tabaci transcriptomes of samples WF2 and WF2b revealed an eleven amino acid residue deletion that was absent in samples WF1 and WF2a. Comparison of the protein structure of the NusG protein from P. aleyrodidarum in SSA1 with known NusG structures showed the deletion resulted in a shorter D loop. Conclusions: The use of field-collected specimens means time and money will be saved in future studies using single whitefly transcriptomes in monitoring vector and viral interactions. Our method is applicable to any small organism where RNA quantity has limited transcriptome studies.

The ecosystem of extra-high mountain areas is very fragile. Understanding local vegetation changes is crucial for projecting ecosystem dynamics. In this paper, we make a case for Himalayan mountain areas to explore vegetation dynamics and their influencing factors. Firstly, the interannual trends of the normalized difference vegetation index (NDVI) were extracted by the Ensemble Empirical Mode Decomposition (EEMD) algorithm and linear regression method. Moreover, the influence of environmental factors on interannual NDVI trends was assessed using the Random Forests algorithm and partial dependence plots. Subsequently, the time-lag effects of seasonal NDVI on different climatic factors were discussed and the effects of these factors on seasonal NDVI changes were determined by partial correlation analysis. The results show that (1) an overall weak upward trend was observed in NDVI variations from 1982 to 2015, and 1989 is considered to be the breakpoint of the NDVI time series; (2) interannual temperature trends and the shortest distance to large lakes were the most important factors in explaining interannual NDVI trends. Temperature trends were positively correlated with NDVI trends. The relationship between the shortest distance to large lakes and the NDVI trend is an inverted U-shaped; (3) the time-lags of NDVI responses to four climatic factors were shorter in Autumn than that in Summer. The NDVI responds quickly to precipitation and downward long-wave radiation; (4) downward long-wave radiation was the main climate factor that influenced NDVI changes in Autumn and the growing season because of the warming effect at night. This study is important to improve the understanding of vegetation changes in mountainous regions.

BACKGROUND: The MEAM1 (B biotype) Bemisia tabaci (Gennadius) is one of the most widespread and damaging whitefly cryptic species. Our previous studies discovered that the MEAM1 whitefly indirectly benefits from interactions with the tomato yellow leaf curl China virus (TYLCCNV) via accelerated ovarian development and increased fecundity. However, the physiological mechanism of begomoviruse-infected plants acting on the reproduction of the insect vector was unknown. METHODOLOGY/PRINCIPAL FINDINGS: Biochemical and molecular properties of vitellogenin (Vg) and vitellin (Vt) were characterized in the MEAM1 whitefly. In addition, kinetics of Vt levels in ovary and Vg levels in hemolymph in different stages were detected using a sandwich ELISA. The level of hemolymph Vg increased rapidly after eclosion. A significantly higher level of hemolymph Vg and ovary Vt were observed in whiteflies feeding on virus-infected tobacco plants than those feeding on uninfected plants. In order to detect the levels of Vg mRNA transcription, complete vitellogenin (Vg) mRNA transcripts of 6474 bp were sequenced. Vg mRNA level in whiteflies feeding on virus-infected plants was higher than those feeding on uninfected plants. However, virus-infection of the whiteflies per se, as demonstrated using an artificial diet system, did not produce significant changes in Vg mRNA level. CONCLUSIONS/SIGNIFICANCE: In MEAM1 whitefly, increased levels of both vitellin and vitellogenin as well as increased transcription of Vg mRNA are associated with feeding on begomovirus-infected plants, thus providing a mechanism for accelerated vitellogenesis. We conclude that MEAM1 whitefly profits from feeding on begomovirus-infected plants for yolk protein synthesis and uptake, and thereby increases its fecundity. These results not only provide insights into the molecular and physiological mechanisms underlying the elevated reproduction of a whitefly species through its association with a begomovirus-infected plant, but also provide a better understanding of the molecular mechanisms related to whitefly reproduction.

BackgroundPlant-pathogenic begomoviruses have a complex association with their insect vectors. The interactions of begomoviruses and reproduction of their vectors are poorly understood. Bemisia tabaci is known to transmit many begomoviruses, and the spread of B. tabaci, especially the B and Q 'biotypes', has been accompanied by the epidemics of begomoviruses. One of these identified disease-causing agents was Tomato yellow leaf curl China virus (TYLCCNV).Methodology/principal findingsIn this study, we compared the egg production and realized fecundity of two 'biotypes' or putative species of the whitefly B. tabaci, including the alien invasive B and the indigenous ZHJ1 from Zhejiang, China, feeding on either healthy or TYLCCNV-infected tobacco plants. The ovary of the whitefly was composed of 12-22 telotrophic ovarioles. According to the morphology of the oocytes and level of yolk content, oocytes in ovarioles were divided into four developmental phases (I-IV). Significantly higher proportion of immature oocytes (phase II, III) and mature oocytes (phase IV) was observed in ovary of females that fed on TYLCCNV-infected tobacco compared to that on healthy plants. Moreover, there was significant increase of eggs laid of B whitefly that fed on TYLCCNV-infected tobacco plants during the early developmental stages. In contrast, the proportion of oocytes of different developmental phases and eggs laid had no significant differences between ZHJ1 whiteflies feeding on TYLCCNV-infected and non-infected host plants.Conclusions/significanceThe invasive B whitefly benefits from feeding on a begomovirus-infected plant through increased egg production and realized fecundity.

The article focuses on a research conducted in order to describe oosorption in the endoparasitic wasp, Pteromalus puparum (P. puparum) in response to starvation. It discusses oosorption as the resorption of oocytes in the ovaries which is usually induced by environmental stress. It further discusses the determination of levels of hemolymph vitellogenin and ovarian vitellin using sandwich enzyme-linked immunosorbent assay in order to understand the mechanism of oosorption in P. puparum.

Seafood consumption is an important route of human exposure to organic contaminants. Residual levels of organochlorine pesticides (OCPs), including DDTs, hexachlorocyclohexanes (HCHs), heptachlor, aldrin, α-endosulfan, β-endosulfan, dieldrin, endrin, endrin aldehyde, endrin ketone, methoxychlor, endosulfan sulfate, and heptachlor epoxide, were determined in a wide variety of seafood products collected from 11 coastal cities in southern China in June and October 2005. The results indicated that OCPs were predominated by DDTs and HCHs. The concentrations of other OCP components generally were low and were detectable in a small number of seafood samples only, probably reflective of the generally low levels of these OCPs in the study region and low bioaccumulation potentials in the species under investigation. Risk assessment against various standards clearly showed that seafood products were highly contaminated by DDTs and may pose health threat to local residents and the consumers all over the world. Furthermore, other OCP components, such as dieldrin and heptachlor, also impose lifetime cancer risk, especially to residents of coastal regions who often consume more seafood than those living inland. Therefore, continual monitoring of OCPs in various environment compartments, including biota and abiota, urgently is needed to mitigate effectively the impact of OCPs, particularly DDTs, on human health and the ecological environment. [ABSTRACT FROM AUTHOR]

Hepatic encephalopathy (HE) is a severe neuropsychiatric syndrome that most commonly occurs in decompensated liver cirrhosis and incorporates a spectrum of manifestations that ranges from mild cognitive impairment to coma. Although the etiology of HE is not completely understood, it is believed that multiple underlying mechanisms are involved in the pathogenesis of HE, and one of the main factors is thought to be ammonia; however, the ammonia hypothesis in the pathogenesis of HE is incomplete. Recently, it has been increasingly demonstrated that inflammation, including systemic inflammation, neuroinflammation and endotoxemia, acts in concert with ammonia in the pathogenesis of HE in cirrhotic patients. Meanwhile, a good number of studies have found that current therapies for HE, such as lactulose, rifaximin, probiotics and the molecular adsorbent recirculating system, could inhibit different types of inflammation, thereby improving the neuropsychiatric manifestations and preventing the progression of HE in cirrhotic patients. The anti-inflammatory effects of these current therapies provide a novel therapeutic approach for cirrhotic patients with HE. The purpose of this review is to describe the inflammatory mechanisms behind the etiology of HE in cirrhosis and discuss the current therapies that target the inflammatory pathogenesis of HE.

Aim: To evaluate the application of bipolar coagulation (BIP) in hepatectomy by comparing the efficacy of BIP alone, cavitron ultrasonic surgical aspirator (CUSA) + BIP and conventional clamp crushing (CLAMP)., Methods: Based on our database of patient records, a total of 380 consecutive patients who underwent hepatectomy at our hospital were retrospectively studied for the efficacy of BIP alone, CUSA + BIP and CLAMP. Of all the patients, 75 received saline-coupled BIP (Group A), 53 received CUSA + BIP (Group B), and 252 received CLAMP (Group C). The pre-, mid-, and postoperative clinical manifestations were compared, and the effects of those maneuvers were evaluated., Results: There was no obvious difference among the preoperative indexes between the different groups. The operative time was longer in Groups A and B than in Group C (P < 0.001 for both). The amount of bleeding and the rate of transfusion during the operation were significantly higher in Group C than in Groups A and B (P < 0.001 for all). The incidence of postoperative complications in Group C (46.43%) was higher than that in Groups A (30.67%, P = 0.015) and B (28.30%, P = 0.016). The patients' liver function recovery and postoperative hospital stay were not significantly different. BIP could decrease intraoperative hemorrhage and postoperative complications compared to CLAMP., Conclusion: Simple saline-coupled BIP should be considered a safe and reliable technique for liver resection to decrease intraoperative hemorrhage and postoperative complications.