Genetic structure of rice black-streaked dwarf virus populations in China.

Rice black-streaked dwarf virus (RBSDV) is a double-stranded RNA (dsRNA) virus belonging to the genus Fijivirus in the family Reoviridae. The genome of RBSDV consists of ten dsRNA segments. Although RBSDV has caused significant economic losses to rice and maize production in the past few years in China, its molecular diversity and evolution remain largely unknown. To elucidate the factor(s) underlying the evolution of RBSDV, we determined segment 8 (S8; carrying ORF8 encoding the minor core capsid protein) sequences of 101 samples and segment 10 (S10; carrying ORF10 encoding the major capsid protein) sequences of 103 samples. The results show that both ORF8 and ORF10 are under negative selection. The S8 of three isolates and S10 of two isolates are recombinants. The RBSDV population in China can be classified into three groups according to S8 sequences or into two groups according to S10 sequences, irrespective of host or geographical origin. Of the RBSDV isolates with both S8 and S10 sequences available, 17 are between-group reassortants and 30 are between-subgroup reassortants. The RBSDV subpopulations from different geographical regions and hosts show frequent gene flow within or between subpopulations. The RBSDV population from maize is in a state of expansion. In this study, no new emergent population was detected. Taken together, the results indicate that, in addition to recombination and negative selection, reassortment and gene flow are important factors that drive evolution of RBSDV in China.

Demographic analysis, a comparison of the jackknife and bootstrap methods, and predation projection: a case study of Chrysopa pallens (Neuroptera: Chrysopidae).

The life table of the green lacewing, Chrysopa pallens (Rambur), was studied at 22 degrees C, a photoperiod of 15:9 (L:D) h, and 80% relative humidity in the laboratory. The raw data were analyzed using the age-stage, two-sex life table. The intrinsic rate of increase (r), the finite rate of increase (lambda), the net reproduction rate (R0), and the mean generation time (T) of Ch. pallens were 0.1258 d(-1), 1.1340 d(-1), 241.4 offspring and 43.6 d, respectively. For the estimation of the means, variances, and SEs of the population parameters, we compared the jackknife and bootstrap techniques. Although similar values of the means and SEs were obtained with both techniques, significant differences were observed in the frequency distribution and variances of all parameters. The jackknife technique will result in a zero net reproductive rate upon the omission of a male, an immature death, or a nonreproductive female. This result represents, however, a contradiction because an intrinsic rate of increase exists in this situation. Therefore, we suggest that the jackknife technique should not be used for the estimation of population parameters. In predator-prey interactions, the nonpredatory egg and pupal stages of the predator are time refuges for the prey, and the pest population can grow during these times. In this study, a population projection based on the age-stage, two-sex life table is used to determine the optimal interval between releases to fill the predation gaps and maintain the predatory capacity of the control agent.

[Effects of temperature on growth, survival, and reproduction of Conogethes punctiferalis feeding on corn kernels]. / 温度对取食玉米籽粒桃蛀螟生长发育、存活和生殖的影响.

In order to examine the effects of temperature on the growth, survival, and reproduction of Conogethes punctiferalis (Lepidoptera: Crambidae) feeding on corn kernels, the life table parameters of C. punctiferalis at 21, 24, 27, 30 ℃ were calculated based on the age-stage two-sex life table theory, and then population dynamics of C. punctiferalis was projected based on these parameters. The results showed that the life cycles of the pest could be finished at all the four temperature treatments. The developmental duration of each stage shortened with increasing temperature, and there were significant differences among treatments. The highest fecundity (116.7 eggs per female), preadult survival rate (84.7%), and proportion of female (0.46) were observed at 24 ℃. The intrinsic rates of increase at 24, 27, 30 ℃ were 0.1059, 0.1101, and 0.1045 d-1, respectively. The finite rates of increase were 1.1117, 1.1164, and 1.1102 d-1, respectively. There was no significant difference among the three treatments, but the r and λ values were significantly higher than those at 21 ℃. The net reproductive rates (R0) at 21, 24, 27, 30 ℃ were 17.3, 53.7, 36.9, and 19.8, respectively. R0 at 24 ℃ was the highest. It suggested that survival rates, fecundities and female proportions of C. punctiferalis population were high at 24-27 ℃, which was the suitable temperature range for its growth, survival, and reproduction.

Demography and Uncertainty of Population Growth of Conogethes punctiferalis (Lepidoptera: Crambidae) Reared on Five Host Plants With Discussion on Some Life History Statistics.

The development, survival, and fecundity data of Conogethes punctiferalis (Guenée) (Lepidoptera: Crambidae) reared on chestnut (Castanea mollissima Blume), maize (Zea mays L.), sunflower (Helianthus annuus L.), hawthorn (Crataegus pinnatifida Bunge), and apple (Malus domestica Miller) were collected at 25 ± 1°C and 70 ± 5% RH. Raw data were analyzed and compared by using the age-stage, two-sex life table. The mean fecundity (F) was the highest (282.3 eggs per female) when larvae were reared on chestnut. The lowest mean fecundity (19.2 eggs per female) occurred on apple. The net reproductive rates (R0) were 134.52, 106.77, 30.29, 27.61, and 8.63 offspring on chestnut, maize, sunflower, hawthorn, and apple, respectively. The intrinsic rates of increase (r) were 0.1359, 0.1326, 0.0807, 0.0811, and 0.0448 d-1 on chestnut, maize, sunflower, hawthorn, and apple, respectively. Computer projections based on the age-stage, two-sex life table revealed the stage structure and variability of the population growth of C. punctiferalis. Our results demonstrated that although chestnut and maize were the most suitable host plants for C. punctiferalis, the moths were also able to develop and reproduce on sunflower, hawthorn, and apple.

A new species of the genus Mongolotettix Rehn, 1928 from Hubei, China (Acrididae, Acridoidea, Orthoptera).

The genus Mongolotettix Rehn, 1928 is a small genus of family Adrididae. It has nine species discovered from the Far Eastern Asian countries, including China, Japan, Korea, Mongolia, and Russia [Bolívar, 1898; Uvarov, 1914; Caudell, 1921; Chogsomzhav, 1974; Li et Lian, 1994; Wan, Ren et Zhang, 1998; Xie et Li, 2000, Kim et Kim 2005; Dong, et al, 2015; Shi et al, 2016; Storozhenko, 2016; Eades et al, 2017; Zhang et al, 2017]. In the present paper, we describe a new species of the genus from Hubei, China. Type specimens are deposited in the College of Plant Protection, Shandong Agricultural University, Taian, Shandong, China.

Two new species and key to six species of the genus Taipodisma Yin, Zheng & Yin, 2014 from Taiwan, China (Orthoptera, Acridoidea, Catantopidae, Podisminae).

Two new species of the genus Taipodisma Yin et al, 2014 from Taiwan, China are described in this paper. The new species Taipodisma viriditibia sp. nov. is similar to Taipodisma hsiehi Yin et al., 2014, it differs from the latter by antennae longer, length of a middle segment 4.0 times its width; interspace of mesosternum longer in male, the length 2.0 times the narrowest; lateral lobes of metasternum slightly separated in male; epiproct of male with longitudinal sulcus at base only and length of subgenital plate of female longer than width. The new species Taipodisma kaohsiungensis sp. nov. is similar to Taipodisma nigritibia Yin et al., 2014, it differs from the latter by prozona of pronotum 1.2 times metazona; length of interspace as long as the narrowest in mesosternum of male; hind tibia yellowish green on lower side and length of subgenital plate longer than width in female. The type specimens are deposited in the National Museum of Natural Science, Taichung, Taiwan, China and the Institute of Entomology, Taiwan University, Taibei, Taiwan, China, respectively.

Two new species of the genus Aalatettix Zheng & Mao (Orthoptera, Tetrigoidea, Tetrigidae) from Taiwan, China.

Two new species of the genus Aalatettix Zheng & Mao, 2002, namely Aalatettix yangi sp. nov. and Aalatettix xiai sp. nov. are described and illustrated. The new species Aalatettix yangi sp. nov. is allied to Aalatettix gibbosa Zheng, Cao & Chen, 2011, but upper margin of pronotum waved in lateral view, width of frontal ridge narrower than width of basal joint of antennae, hind tibiae dark brown, base not pale. The new species Aalatettix xiai sp. nov. is allied to Aalatettix yangi sp. nov., but length of pronotum shorter, not reaching epiproct, width of vertex 1.5 times diameter of eye, lateral carinae of pronotum contracted backward distinctly, posterior apex of lower margin angular on lateral lobe of pronotum, lower margin of median femur waved, antennae placed under lower margin of eyes. The type specimens are deposited in the National Museum of Natural Science, Taichung, Taiwan, China.

Discovery of a new species of Formosatettix Tinkham, 1937 (Orthoptera, Tetrigoidea, Tetrigidae) from China.

A new species of the genus Formosatettix Tinkham, 1937, namely Formosatettix xiai sp. n. is described and illustrated. The new species is allied to Formosatettix wulaoshanensis Zheng & Xu, 2010, but differs from the latter by the apex of pronotum reaching distal 2/3 of hind femur, width of frontal ridge equal to that of basal segment of antennae, length of a segment of antennae in the middle 3 times its width, lower margin of fore and mid femora straight, pronotum dorsally with one black spot on each side. The new species is also allied to Formosatettix tianmushanensis Zheng & Li, 2001, but the apex of pronotum reaching distal 2/3 of hind femur, the width of frontal ridge equal to that of basal antennal segment, length of upper ovipositor valve 3 times its width, length of a segment in the middle of antennae 5.0 times its width and pronotum dorsally with one black spot on each side. The type specimens are deposited in the College of Life Sciences, Hebei University, Baoding, Hebei, China.

[Spatial distribution patterns of adult population of Pseudorobitis gibbus (Coleoptera: Apionidae) in Taixing Garden, Tai'an, Shandong, China].

The vertical and horizontal distributions of Pseudorobitis gibbus adults on Lagerstroemia indica were analyzed by using the aggregation indices and geostatistics. The results from aggregation index methods indicated that its vertical distribution was an aggregated distribution, and the aggregation average (lambda) was above two, showing that the aggregation resulted from its bionomics and behaviors, not from the environmental factors. The results of geostatistic analysis showed that the best fitting models for the five different sampling data in June 4, June 16, June 29, July 25 and August 22 were Gaussian, Gaussian, Linear, Gaussian and Linear models, respectively, but random models in July 12 and August 7. It was concluded that the horizontal distribution of the pest was aggregated on the whole, and there existed a spatial correlation ranging from 1.68 to 9.79 m on the different dates.

[Effects of fluctuating thermal regime on cold tolerance of parasitoid wasp Aphidius gifuensis].

In order to understand the effects of fluctuating thermal regime (FTR) on the cold tolerance of female and male Aphidius gifuensis adults in the mummies of Schizaphis graminum and to explore the variation patterns of the biochemical substances in the adult body, this paper determined the supercooling point (SCP), freezing point (FP), and the water, fat, protein, and carbohydrate contents of the adults after FTR treatments. Compared with that at constant temperature (20 degrees C), the cold tolerance of the adults at 4 degrees C 22 h/20 degrees C 2 h and 4 degrees C 46 h/20 degrees C 2 h after 1 week enhanced significantly. The SCP and FP after FTR presented a downtrend, being the lowest (-26.38 degrees C and -25.51 degrees C, respectively) for the female adults after 1 week of 4 degrees C 22 h/20 degrees C and the lowest (-26.82 degrees C and -26.38 degrees C, respectively) for the male adults after 1 week of 4 degrees C 46 h/20 degrees C 2 h. After FTR, the carbohydrate and protein contents of the female and male adults increased while the fat and water contents were in adverse, with distinct changes after 1 week of 4 degrees C 22 h/20 degrees C 2 h and 4 degrees C 46 h/20 degrees C 2 h. The results indicated that FTR could enhance the cold tolerance of A. gifuensis adults, which was closely related to the variations of the biochemical substances in the adult body, and the treatments 4 degrees C 22 h/20 degrees C 2 h and 4 degrees C 46 h/20 degrees C 2 h for 1 week were most advantageous to the survival and practical application of A. gifuensis.

Molecular characterization of segments S7 to S10 of a southern rice black-streaked dwarf virus isolate from maize in northern China.

Southern rice black-streaked dwarf virus (SRBSDV) is a novel Fijivirus prevalent in rice in southern and central China, and northern Vietnam. Its genome has 10 segments of double-stranded RNA named S1 to S10 according to their size. An isolate of SRBSDV, JNi4, was obtained from naturally infected maize plants from Ji'ning, Shandong province, in the 2008 maize season. Segments S7 to S10 of JNi4 share nucleotide identities of 72.6%-73.1%, 72.3%-73%, 73.9%-74.5% and 77.3%-79%, respectively, with corresponding segments of Rice black-streaked dwarf virus isolates, and identities of 99.7%, 99.1%-99.7%, 98.9%-99.5%, and 98.6%-99.2% with those of SRBSDV isolates HN and GD. JNi4 forms a separate branch with GD and HN in the phylogenetic trees constructed with genomic sequences of S7 to S10. These results confirm the proposed taxonomic status of SRBSDV as a distinct species of the genus Fijivirus and indicate that JNi4 is an isolate of SRBSDV. Shandong is so far the northernmost region where SRBSDV is found in China.

[Quantitative analysis of insect pest and natural enemy communities in Red Fuji apple orchard].

The insect pest and natural enemy communities in Red Fuji apple orchard in Mouping District of Yantai City were quantitatively analyzed by multivariate analysis. The temporal structure of the communities was grouped into five continuous stages by using optimal sorting method, and the community characteristics at each stage were described. The dominant pests and natural enemies were determined at different growth stages of apple trees through analyzing the sub-communities of the insect pests and the predatory and parasitic enemies by principal component analysis and factor analysis. Canonical correlation analysis showed that there were significant correlations between the dominant insect pests and the dominant natural enemies, especially between Lithocolletis ringoniella and its parasitoids, between Aphis citricola and its parasitoids, and between Tetranychus viennensis and its obligatory predatory enemies, Stethorus punctillum and Amblyseius orientalis.