Cheng JiaAn

The Seasonal Occurrence, Forecasting and Management Strategy for Brown Planthopper in Zhejiang, China

Abstract Analysis of historical and experimental data collected in Jiaxing, Zhejiang Province, China, indicated the population development pattern there was a typical temperate type with low immigration and high growth rate. Population dynamics was affected by temperature, variety and natural control agents, as well as immigration. Forecasting process was described and prediction could be improved by using multi-regression models incorporating immigration size, percentage of area grown resistant varieties and temperature in mid-September. An ecological approach for improvement of BPH management was proposed, because frequent outbreak in temperate regions was mainly resulted from high growth rate there and inappreciative chemical control might cause resurgence.

LETHAL AND SUBLETHAL EFFECTS OF ACETAMIPRID ON THE LARVAE OF CULEX PIPIENS PALLENS

Abstract Acetamiprid is a novel neonicotinoid insecticide invented by Nippon Soda Co., Ltd. To explore the possibility of acetamiprid as larvicide of mosquitoes, lethal and sublethal effects of acetamiprid on the larvae of Culex pipiens pallens were studied by immersion method in the laboratory. The results indicated that the larvae of Culex pipiens pallens were sensitive to acetamiprid. The mortality of larvae peaked at 72 h after treatment. The 1 st instar larvae was the most susceptible to acetamiprid, and the 4th instar larvae was the most tolerant to acetamiprid, the LC, values were 0. 020 mg/L and 0. 296 mg/L at 72 h after treatment, respectively. Sublethal concentrations of acetamiprid could delay the development of larvae and decrease the weight of pupa. We suggested that acetarniprid is a safe and effective substitute for the using larvicides of mosquitoes.

CLONING AND COMPARISON OF THE GENES ENCODING PREPROAPAMIN FROM THE VENOM OF 2 HONEYBEE AND 4 WASP SPECIES

Abstract Preproapamin genes were amplified by RT‐PCR from total RNA from the venom glands of 2 honeybee species, Apis mellifera, A. cerana cerana, and 4 wasp species, Vespa magnifica, V. velutina nigrothorax and Polistes hebraeus, respectively. Their PCR products were ligated into pGEM® ‐T easy vector and the nucleotide sequences analyzed. The six fragments were all 141 bp in length and contained an ORF coding the precursor of apamin. The apamin precursors of V. magnifica, V. velutina nigrothorax and P. hebraeus had 95% and 93% similarity with that of A. melliera in nucleotide and amino acid sequences, respectively. That of Vespula maculifrons was identical to that of A. mellifera in nucleotide and amino acid sequences. Apamin precursors of V. magnifica, P. hebraeus and V. velutina nigrothorax also had the same nucleotide sequences. The nucleotide sequences of preproapamin genes from the Chinese honeybee, A. cerana cerana and 4 wasp species are described for the first time. A notable discovery was that the wasps species had exactly same apamins as the honeybees despite the fact they belong to different insect families.

STUDIES ON CULTIVAR‐INDUCED CHANGES IN INSECTICIDE SUSCEPTIBILITY AND ITS RELATED ENZYME ACTIVITIES OF THE WHITE BACKED PLANTHOPPER, SOGATELLA FURCZFERA (HORVÁTH) (HOMOPTERA:DELPHACIDAE)

Abstract  The susceptibility of Sogatella furcifera female adults on N22 to malathion increased as feeding time prolonged, while the day change of susceptibility to isoprocarb showed a inverse tendency. The activities of esterase and carboxylesterase were induced significantly after on N22 for one day, and then declined. The non‐susceptible level of adults to insecticides and enzyme activities seemed to be heightened after feeding on ASD7, a variety resistant to Nilaparvata lugens. The total phenol content in rice leaf sheath was the highest in N22, and could be regaded as one of the factors, which caused chages in susceptibility of S. furicfera to insecticide after feeding different rice varieties. It was recommended that suitable insecticides and planthopper resistant varieties should be coordinately used in practice 90 that they contribute more effects respectively.

A large scale screen for genes (3rd chromosome) related to Wingless signaling pathway

A wing specific F1 genetic screen was carried out using the powerfulDrosophila genetic system, combined with yeast FRT/FLP and GAL4/UAS system. Form the wing phenotypes and germline clone embryonic cuticle phenotypes observed in these mutant alleles, a number of mutant alleles of known or unknown genes were isolated. Among them, fifteen mutant alleles related to Wingless signal transduction were further isolated; the arm of these mutations located were determined, and their location in the chromosome were roughly mapped.A wing specific F1 genetic screen was carried out using the powerfulDrosophila genetic system, combined with yeast FRT/FLP and GAL4/UAS system. Form the wing phenotypes and germline clone embryonic cuticle phenotypes observed in these mutant alleles, a number of mutant alleles of known or unknown genes were isolated. Among them, fifteen mutant alleles related to Wingless signal transduction were further isolated; the arm of these mutations located were determined, and their location in the chromosome were roughly mapped.

CELLULAR LOCALIZATION AND EXPRESSION OF pygo DURING DROSOPHILA DEVELOPMENT

Abstract Wg/Wnt signaling is a key signaling pathway in Drosophila. Many genes involved in Wingless(wg) signal transduction pathway downstream of Wg, or it s vertebrate Wg homologue Wnt, have been identified. Transduction of the Wg signal downstream of Wg is mediated by nuclear TCF/LEF‐1, through association with Armadillo (Arm)β‐catenin. Pygopus (pygo) is a new identified component in this pathway. Cellular localization experiment showed that pygo was expressed specifically in the nucleus. The expression profile of pygo in embryos was examined using in situ hybridization. Although pygo expressed ubiquitously in the embryos, it expressed at relatively high level in pre‐blastoderm embryos which indicate a high degree of maternally provided message, followed by a low level of ubiquitous zygotic expression. This continues into larval tissues (including wing disc, eye disc and leg disc), where pygo appears to be expressed at low level. Comparison of pygo expression levels, in the wing disc, eye disc and leg disc, showed pygo expression level in the wing disc pouch and leg disc were relative higher.

CLONING AND SEQUENCING OF GENE ENCODING HYALURONIDASE FROM THE VENOM OF APIS CERANA CERANA

Abstract The venomous hyaluronidase (Hya) gene of Chinese honey bee, Apis cerana cerana, was amplified by RT‐PCR from total RNA of venom glands of the worker bees. The full length of its nucleotide is 1164 bp encoding a 387 amino acid polypeptide with predicted molecular weight of 42.6 kD. The alignment of AcHya amino acid sequence with other 6 Hyas shows that AcHya is most closely related to the Hya of European honey bee, A. mellifera, with 91% amino acid identity. It also shares homology with Hya of Dolichovespul amacidata, Polistes annularis, Vespula vulgaris, Lutzomia longipalpis and Homo sapiens (sperm), with 54%., 52%., 46%, 27% and 20% amino acid identity, respectively. A phylogenetic tree of those hyaluronidases was drawn by using GENETYX program, the conservation, the relationship between molecular structure and function of 7 hyaluronidases as above was compared and analysed.

ROLE OF RICE VOLATILES IN THE FORAGING BEHAVIOUR OF CYRTORHINUS LIVIDIPENNIS REUTER

Abstract Experiments were conducted in laboratory to study the impacts of rice genotypes and nitrogen levels on the preference of the egg predator, Cyrtorhinus lividipennis, for eggs of brown planthopper(BPH), Nilaparvata lugens (Stal), and their relation to the rice volatiles. In two‐choice tests, the female predators showed different preference for BPH eggs on different rice genotypes, but not for BPH eggs on rice plants treated with different levels of nitrogen. The olfactory response test revealed that more predator oriented to the odour from healthy rice plants compared with the plain air (control); the predator preferred BPH nymph‐damaged plants to healthy plants, and BPH female adult‐damaged plants to BPH nymph‐damaged plants. The comparative studies between rice genotypes and nitrogen levels indicated that there were obvious differences in attractiveness to the predator between rice genotypes, while there was no significant difference between rice plants treated with different levels of nitrogen. The results showed that rice volatiles played an important role in mediating the foraging behaviour of C. lividipennis. Implications for augmenting the effectiveness of natural enemies by adjusting rice attributes and cultural practices are discussed.