During China's rapid urbanization process, the survival condition of low-income college graduates who live in urban villages has become a serious issue that attracts the attention of policy-makers and sociologists...During China's rapid urbanization process, the survival condition of low-income college graduates who live in urban villages has become a serious issue that attracts the attention of policy-makers and sociologists. Based on existing literatures, relevant information, and independent field investigations, this paper focuses on Tangjialing, an urban village where low-income college graduates gather, investigating on their current situations of sociological features and settlements, as well as the reasons for the formation of urban villages.展开更多
The aggregation components from fecal volatiles of the oriental mi- gratory locust, Locusta migratoria manilensis were identified with gas chromatographic/electroantennographic detector （GC-EAD）, GC-MS （mass spectr...The aggregation components from fecal volatiles of the oriental mi- gratory locust, Locusta migratoria manilensis were identified with gas chromatographic/electroantennographic detector （GC-EAD）, GC-MS （mass spectrometry） analyses and behavioral bioassays. Both last instar nymphs and adults of the oriental migratory locust have similar aggregation pheromones in their volatiles. A total of 11 electrophysiologically active compounds, namely, hexanal, cyclohexanol, heptanal, phenol, 2,5-dimethyl- pyrazine, benzyl alcohol, benzaldehyde, guaiacol, nonanal, 2,6,6-trimethyl-2-cyclohexene- 1,4-dione and decyl aldehyde were identified in the fecal volatiles of 2-day-old immature adult male locusts. Only hexanal, nonanal, benzaldehyde, cyclohexanol and 2,5-dimethyl- pyrazine elicited significant aggregation responses in immature 2-day-old adult males. However, adult males had significantly lower behavioral responses to synthetics of five single compounds than the blend of cyclohexanol, 2,5-dimethyl-pyrazine, benzaldehyde, nonanal, hexanal in ratios of 100 ： 100 ： 2 ： 60 ： 30 in the range of 30 60 μg/mL. We propose that it is the blend of these five compounds that plays a key role in eliciting and sustaining aggregation in gregarious oriental migratory locusts. These results also showed that the aggregation pheromones of the oriental migratory locust are significantly different from those found in the desert locust.展开更多
文摘During China's rapid urbanization process, the survival condition of low-income college graduates who live in urban villages has become a serious issue that attracts the attention of policy-makers and sociologists. Based on existing literatures, relevant information, and independent field investigations, this paper focuses on Tangjialing, an urban village where low-income college graduates gather, investigating on their current situations of sociological features and settlements, as well as the reasons for the formation of urban villages.
基金The authors thank Dr. David Hunter for carefully editing the manuscript. I am grateful to Prof. Hassanali Ahmed and Dr. Njagi Peter in International Centre of Insect Physiology and Ecology, L. Zhang in China Agricultural University, Prof. C. H. Wu in Beijing University and Dr. X. B. Kong in Chinese Academy of Forestry for the suggestions and comments that improved the manuscript. This research was funded by the National Natural Science Foundation of China and Offer of Scientist Exchange Visit of ICIPE.
文摘The aggregation components from fecal volatiles of the oriental mi- gratory locust, Locusta migratoria manilensis were identified with gas chromatographic/electroantennographic detector （GC-EAD）, GC-MS （mass spectrometry） analyses and behavioral bioassays. Both last instar nymphs and adults of the oriental migratory locust have similar aggregation pheromones in their volatiles. A total of 11 electrophysiologically active compounds, namely, hexanal, cyclohexanol, heptanal, phenol, 2,5-dimethyl- pyrazine, benzyl alcohol, benzaldehyde, guaiacol, nonanal, 2,6,6-trimethyl-2-cyclohexene- 1,4-dione and decyl aldehyde were identified in the fecal volatiles of 2-day-old immature adult male locusts. Only hexanal, nonanal, benzaldehyde, cyclohexanol and 2,5-dimethyl- pyrazine elicited significant aggregation responses in immature 2-day-old adult males. However, adult males had significantly lower behavioral responses to synthetics of five single compounds than the blend of cyclohexanol, 2,5-dimethyl-pyrazine, benzaldehyde, nonanal, hexanal in ratios of 100 ： 100 ： 2 ： 60 ： 30 in the range of 30 60 μg/mL. We propose that it is the blend of these five compounds that plays a key role in eliciting and sustaining aggregation in gregarious oriental migratory locusts. These results also showed that the aggregation pheromones of the oriental migratory locust are significantly different from those found in the desert locust.
