Centers of endemism and diversity patterns for typhlocybine leafhoppers （Hemiptera： Cicadellidae： Typhlocybinae） in China

This study identifies ＇centers of endemism＇ for typhlocybine leafhoppers in China, revealing diversity patterns and congruence of patterns between total species rich- ness and endemism. Distribution patterns of 774 Typhlocybinae （607 described and 167 undescribed species） were mapped on a 1.5° × 1.5° latitude/longitude grid. Total species richness, endemic species richness and weighted endemism richness were calculated for each grid cell. Grid cells within the top 5% highest values of weighted endemism richness were considered as ＇centers of endemism＇. Diversity patterns by latitude and altitude were obtained through calculating the gradient richness. A congruence of diversity patterns between total species richness and endemism was confirmed using correlation analysis. To investigate the bioclimatic factors （19 variables） contributing to the congruence be- tween total species richness and endemism, we compared the factor＇s difference between non-endemic and endemic species using the Kruskal-Wallis test. Eleven centers of en- demism, roughly delineated by mountain ranges, were identified in central and southern China, including the south Yunnan, Hengduan Mountains, Qinling Mountains, Hainan Is- land, Taiwan Island and six mountain areas located in western Sichuan, northwest Fujian, southeast Guizhou, southeast Hunan, central and western Guangdong, and north Zhejiang. Total species richness and endemic species richness decreased with increased latitude and had a consistent unimodal response to altitude. The proportions of endemism decreased with increased latitude and increased with rising altitude. Diversity patterns between total species richness and endemism were highly consistent, and ＇Precipitation of Coldest Pe- riod＇ and ＇Temperature of Coldest Period＇ may contribute to the congruence of pattern. Migration ability may play a role in the relationship of endemism and species richness; climate, environment factors and important geologic isolation events can also play crucial effects on relationships under special conditions.

Microelectrona cladara gen.et sp.nov.:A New Protodikraneurini from the Eocene Baltic Amber(Hemiptera:Cicadomorpha:Cicadellidae:Typhlocybinae)

A new genus Microelectrona gen. nov. and species Microelectrona cladara sp. nov. of the extinct tribe Protodikraneurini of the leafhoppers （Cicadellidae： Typhlocybinae） from the Eocene Baltic amber is described. The piece of amber containing leafhopper inclusion is broken, unveiling some of the morphological structures, and enabling their studies using scanning electron microscopy.

Exploiting push-pull strategy to combat the tea green leafhopper based on volatiles of Lavandula angustifolia and Flemingia macrophylla

Thirteen volatile compounds were identified from Flemingia macrophylla plants. Eight major components significantly attracted the tea green leafhoppers, Empoasca flavescens F. Based on their relative abundances, following synthetic blends were made for field experiments: 1) eight-component-attractant blend included Z-3-hexen-1-ol, Z-3-hexenyl acetate, Z-ocimene, Me SA, Z-3-hexenyl butyrate, dodecane, hexadecane and nonanal at 10, 10, 1, 11, 2, 6, 2 and 4 mg mL^-1 in n-hexane, respectively;2) four-component-attractant blend #1 contained hexadecane, Z-3-hexenyl acetate, Z-3-hexen-1-ol and nonanal at 2, 10, 10 and 4 mg mL^-1 in n-hexane, respectively;3) four-component-attractant blend #2 contained hexadecane, Z-3-hexenyl acetate, Z-3-hexen-1-ol and Me SA at 2, 10, 10 and 11 mg mL^-1 in n-hexane, respectively. Thymol and 1-methoxy-4-methyl-2-(1-methylethyl)-benzene, identified from Lavandula angustifolia aeration samples, significantly repelled the leafhopper as strong repellents when tested alone or in combination at 10 mg mL^-1. For field bioassays, each attractant lure was attached to a bud green sticky board hung from a bamboo stick at above tea plant level for catching the leafhoppers, whereas the repellent dispenser was tied to a tea branch inside tea clump for pushing the leafhoppers away from tea clumps. The results showed that the eight-component-attractant blend caught similar numbers of the leafhopper as did the four-component-attractant blend #1 at about 53–79 leafhoppers/trap/day, which were significantly higher than those on the hexane-control bud green sticky boards. Average leafhopper catches from un-baited sticky boards were about 51–73 leafhoppers/trap/day when pushed by the repellents placed inside tea plants, with the two-component-repellent blend being more effective than their single components. When the two-component-repellent blend was further tested with the three attractant blends in a push-pull fashion, average trap catches ranged from 62 to 92 leafhoppers/trap/day. Control efficacy on the leafhoppers within the push-pull zones increased progressively from day 1(43%) to day 5(73%). This push-pull approach might have a great potential as a green control strategy for combating the tea green leafhoppers.

Field Efficacy Trial of Trapping Tea Green Leafhopper with Pheromone Insect-attracting Board

[Objective]The paper was to study the control effect of pheromone insect-attracting board on tea green leafhopper（Empoasca vitis Gothe）in fields. [Method]Pheromone insect-attracting board and ordinary insect-attracting board were used to trap tea green leafhopper in fields,and control efficacies were studied.[Result]The daily trapping effect of pheromone insect-attracting board on tea green leafhopper was 19.0 insect/grid,while that of ordinary insect-attracting board was 13.8 insect/grid.The highest control effect of pheromone insect-attracting board and ordinary insect-attracting board were 71.6% and 63. 6%,respectively.The distribution of tea green leafhopper in two types of boards showed the following regularities：more in upper edge and less in lower edge of boards,more on both sides and less in the middle of boards.The mean values of control effects of two insect-attracting boards were significantly different（t =5.66

Characterization of Resistance to the Green Rice Leafhopper (<i>Nephotettix cincticeps</i>Uhler) in a Core Collection of Landraces in Rice (<i>Oryza sativa</i>L.)

The green rice leafhopper (GRH;Nephotettix cincticeps Uhler) is one of the most devastating insect pests of cultivated rice (Oryza sativa L.) in temperate regions in Asia. Using the rice germplasms with biotic stress resistance is the most effective and environmentally-friendly way to control the insect pests in the paddy. Sixty accessions from a core set of worldwide collection of rice were characterized for resistance to the GRH by antibiosis test both at the seedling and at the booting stages. The positive correlations of average nymph mortality (ANM) were observed between at the seedling stage and at the booting stage on 3 days after infestation (DAI) (r = 0.684**), 5DAI (r = 0.680**), and 7DAI (r = 0.652**), respectively. This result will give us the opportunity to screen resistance to the GRH with the cost-efficient way using rice seedlings in a growth chamber. To classify the 60 accessions evaluated, the ANM of the GRH of each accession was compared to the respective ANM of resistant and susceptible controls with the least significant difference (LSD) value. Based on the statistical difference or similarity of the ANMs to the resistant and the susceptible controls, we proposed the four groups of resistance to the GRH, (I) high level of resistance, (II) considerable level of resistance, (III) moderate level of resistance, and (IV) susceptibility. At the seedling stage, a total of 26 accessions were highly resistant in addition to other 6 for considerable level of resistance and other 10 for moderate level of resistance. At the booting stage, on the other hand, a total of 18 accessions were highly resistant in addition to other 3 for considerable level of resistance and other 5 for moderate level of resistance. A total of 42 accessions with high to moderate level of resistance were distributed across 16 countries in Asia in addition to each one for Madagascar and USA. The classification of landraces based on the present protocol for screening resistance to the insect provided fundamental information for genetics and breeding on resistance to the GRH in rice.

Synthetic brochosomes:Design,synthesis,and applications

Brochosomes,which are nanoscopic buckyball-shaped granules produced by leafhoppers,are one of the most intricate structures discovered in nature.Various functions of brochosomes have been proposed but only a few have been experimentally validated due to the challenge of fabricating their synthetic counterparts.Advancements in micro-and nanofabrication have recently led to the emergence of synthetic brochosomes,opening up new possibilities for innovative applications.This review explores the early discovery of natural brochosomes and their geometrical features,followed by the recent progress in fabricating synthetic brochosomes and their applications.Perspectives on future applications and challenges in the scalable manufacturing of synthetic brochosomes are discussed.

Factors shaping life history traits of two proovigenic parasitoids

What shapes the relative investment in reproduction versus survival of organisms is among the key questions in life history.Proovigenic insects mature all their eggs prior to emergence and are short lived,providing a unique opportunity to quantify their lifetime investments in the different functions.We investigated the initial eggloads and longevity of 2 proovigenic parasitoid wasps:Anagrus erythroneurae and Anagrus daanei,(Hymenoptera:Mymaridae)that develop within leafhopper eggs in both agricultural vineyards and natural riparian habitats in Northern California.We collected Vitis spp.leaves containing developing parasitoids from 3 natural sites(Knight Landing,American River and Putah Creek)and 3 agricultural vineyards(Solano Farm,Davis Campus and Village Homes).We recorded eggloads at parasitoid emergence and female parasitoid longevity with or without honey-feeding.Theory predicts that parasitoids from vineyards(where hosts are abundant)would have higher initial eggloads and lower longevity compared with parasitoids from riparian habitats(where hosts are scarce).Although host density and parasitoid eggloads were,indeed,higher in vineyards than in riparian habitats,parasitoid longevity did not follow the predicted pattern.Longevity without feeding differed among field sites,but it was not affected by habitat type(natural vs agricultural),whereas longevity with feeding was not significantly affected by any of the examined factors.Moreover,longevity was positively,rather than negatively,correlated with eggloads at the individual level,even after correcting for parasitoid body size.The combined results suggest a more complex allocation mechanism than initially predicted,and the possibility of variation in host quality that is independent of size.

Behavioral responses for evaluating the attractiveness of specific tea shoot volatiles to the tea green leafhopper, Empoaca vitis

The tea green leafhopper, Empoasca vitis Gothe, is one of the most serious insect pests of tea plantations in China's Mainland. Over the past decades, this pest has been controlled mainly by spraying pesticides. Insecticide applications not only have become less effective in controlling damage, but even more seriously, have caused high levels of toxic residues in teas, which ultimately threatens human health. Therefore, we should seek a safer biological control approach. In the present study, key components of tea shoot volatiles were identified and behaviorally tested as potential leafhopper attractants. The following 13 volatile compounds were identified from aeration samples of tea shoots using gas chromatography-mass spectrometry （GC-MS）： （E）-2-hexenal, （Z）-3-hexen-1- ol, （Z）-3-hexenyl acetate, 2-ethyl-1-hexanol, （E）-ocimene, linalool, nonanol, （Z）-butanoic acid, 3-hexenyl ester, decanal, tetradecane, β-caryophyllene, geraniol and hexadecane. In Y-tube olfactometer tests, the following individual compounds were identified： （E）-2- hexenal, （E）-ocimene, （Z）-3-hexenyl acetate and linalool, as well as two synthetic mixtures （called blend 1 and blend 2） elicited significant taxis, with blend 2 being the most attractive. Blend 1 included linalool, （Z）-3-hexen-l-ol and （E）-2-hexenal at a 1： 1：1 ratio, whereas blend 2 was a mixture of eight compounds at the same loading ratio： （E）-2-hexenal, （Z）- 3-hexen-l-ol, （Z）-3-hexenyl acetate, 2-penten-l-ol, （E）-2-pentenal, pentanol, hexanol and 1-penten-3-ol. In tea fields, the bud-green sticky board traps baited with blend 2, （E）-2- hexenal or hexane captured adults and nymphs of the leafhoppers, with blend 2 being the most attractive, foUowed by （E）-2-hexenal and hexane. Placing sticky traps baited with blend 2 or （E）-2-hexenal in the tea fields significantly reduced leathopper populations. Our results indicate that the bud-green sticky traps baited with tea shoot volatiles can provide a new tool for monitoring and managing the tea leafhopper.

The reproductive strategy and the vibrational duet of the leafhopper Empoasca vitis

The recent description of a new vibrational mating disruption method to control the leafhopper Scaphoideus titanus Ball opened questions about its possible application to other leafhopper pests. Since the prerequisite for the method＇s successful application is a deep knowledge of the species mating behavior and the exact role of associated signals, we conducted behavioral assays on the green leafhopper Empoasca vitis Gothe, a pest of grapevine and other crops in Europe and Asia. Laser vibrometer recordings of single and paired individuals （male and female） during a 24-h period enabled us to detect and describe 2 male and 1 female signal. The pair formation starts when the female replies to a male call and a duet is established, then it continues through 2 different behavioral stages： Location and Courtship. The proper courtship begins only when the male locates the female. The latter is characterized by a significant change in temporal parameters that regards both the signals and the duet structure. Although the male calling activity and the female replying rate were the same during the 24 h, a lower number of matings was recorded during the night. We discuss the possible role of vision and of the species ecology as factors of reproductive success and mating strategy. Our conclusion is that the mechanical mating disruption technique seems feasible for future application to this species.

Rice yellow stunt virus activates polyamine biosynthesis to promote viral propagation in insect vectors by disrupting ornithine decarboxylase antienzyme function

Intracellular polyamines(putrescine,spermidine,and spermine)have emerged as important molecules for viral infection;however,how viruses activate polyamines biosynthesis to promote viral infection remains unclear.Ornithine decarboxylase 1(ODC1)and its antienzyme 1(OAZ1)are major regulators of polyamine biosynthesis in animal cells.Here,we report that rice yellow stunt virus(RYSV),a plant rhabdovirus,could activate putrescine biosynthesis in leafhoppers to promote viral propagation by inhibiting OAZ1 expression.We observed that the reduction of putrescine biosynthesis by treatment with difluormethylornithine(DFMO),a specific nontoxic inhibitor of ODC1,or with in vitro synthesized dsRNAs targeting ODC1 mRNA could inhibit viral infection.In contrast,the supplement of putrescine or the increase of putrescine biosynthesis by treatment with ds RNAs targeting OAZ1 mRNA could facilitate viral infection.We further determined that both RYSV matrix protein M and ODC1 directly bind to the ODC-binding domain at the C-terminus of OAZ1.Thus,viral propagation in leafhoppers would decrease the ability of OAZ1 to target and mediate the degradation of ODC1,which finally activates putrescine production to benefit viral propagation.This work reveals that polyamine-metabolizing enzymes are directly exploited by a vector-borne virus to increase polyamine production,thereby facilitating viral infection in insect vectors.

Genomic Variations in the Tea Leafhopper Reveal the Basis of Its Adaptive Evolution

Tea green leafhopper(TGL),Empoasca onukii,is of biological and economic interest.Despite numerous studies,the mechanisms underlying its adaptation and evolution remain enigmatic.Here,we use previously untapped genome and population genetics approaches to examine how the pest adapted to different environmental variables and thus has expanded geographically.We complete a chromosome-level assembly and annotation of the E.onukii genome,showing notable expansions of gene families associated with adaptation to chemoreception and detoxification.Genomic signals indicating balancing selection highlight metabolic pathways involved in adaptation to a wide range of tea varieties grown across ecologically diverse regions.Patterns of genetic variations among 54 E.onukii samples unveil the population structure and evolutionary history across different tea-growing regions in China.Our results demonstrate that the genomic changes in key pathways,including those linked to metabolism,circadian rhythms,and immune system functions,may underlie the successful spread and adaptation of E.onukii.This work highlights the genetic and molecular basis underlying the evolutionary success of a species with broad economic impacts,and provides insights into insect adaptation to host plants,which will ultimately facilitate more sustainable pest management.