Aim] This study aims to determine the source areas and the landing mechanisms of the immigration populations of the white-backed planthopper (WBPH), Sogatella furcifera (Horvath), in Dazhou, Sichuan Province, so as to provide a basis for the warning and effective control of this pest in eastern Sichuan, southwestern China. Methods] Based on the data of the daily light-trap catches of S. furcifera in Dazhou from 1991 to 2013, the trajectory simulation and the meteorological background of immigration peaks of S. furcifera were analyzed by HYSPLIT 4.8 (Hybrid Single-Partical Langrangian Integrated Trajectory) and GRADS (Grid Analysis and Display System). Results] The main immigration period of S. furcifera in Dazhou was from June to July, with a peak season in July. The mass immigration of S. furcifera into Dazhou in June was from the northwest and the central of Guangxi. In July, the major source areas were the central, west and north of Guizhou, and the secondary source areas were the northwest of Guangxi a
This study aims to understand the structure of the antennal lobe (AL) of the tobacco cutworm, Spodoptera litura and its neuronal activities in response to plant volatiles and sex pheromones. The structure of the antennal lobe of S. litura adults was scanned and observed by using the confocal laser scanning. The ALs in the brain of S. litura adults identified in the confocal laser scanning were composed of 67 and 66 glomeruli in males and females, respectively. The total and average volumes of glomeruli in female adults were higher than those in male adults. The MR results showed three spontaneous discharge patterns of neurons, i. e., diffuse spiking (irregular frequency), moderate spiking (slower and broader distributional frequency), and fast spiking (bursting high frequency). Three types of neuron responses to odor stimulation were present in all recordings, i. e., excitatory, inhibitory, and unresponsive.
Three new species of the genus Niitakacris Tinkham, 1936 from Taiwan, China are described in the present paper, including N. arishanensis sp. nov., N. xiai sp. nov., and N. taiwanensis sp. nov. N. arishanensis sp. nov. differs from all known species of the genus by the hind femur not red on inner side and maximum width of basal part 4 times width of apical part in cercus of male. N. xiai sp. nov. is similar to N. rosaceanum (Shiraki, 1910) and Niitakacris taiwanensis sp. nov., but differs from the two species by the length of interspace of mesostemum longer than minimum width and tegmina not reaching the hind margin of first abdominal tergite. N. taiwanensis sp. nov. is similar to N. rosaceanum (Shiraki, 1910), but differs from the latter by eye smaller, vertical diameter 1.4 times subocular furrow; furculae separated; longitudinal groove at base of epiproct shorter, not reaching to the middle, apex rounded. A key to all five species of the genus from Taiwan is given. Type specimens are deposited in the Natio
The present study aims to investigate the mediated functions of carboxylesterases in fipronil resistance of the diamondback moth, Plutella xylostella (L.), and thus to reveal the physiological, biochemical, and molecular mechanisms of carboxylesterases in metabolic detoxification of insects. Topical application was used to test the toxicity of fipronil to the susceptible population (SP) and the fipronil-resistant population (FRP) and the synergistic effect of triphenyl phosphate (TPP), a carboxylesterase inhibitor, on fipronil. The results showed that TPP decreased the resistance of the 3rd instar larvae of P. xylostella to fipronil by about six times. After treatment with the lower doses (LC sub(30) and LC sub(50)) of fipronil, the carboxylesterase activity in the treated 3rd instar larvae of P. xylostella was significantly higher than that of the control, suggesting that the carboxylesterase activity in P. xylostella could be induced by fipronil.
Body size, a fundamental morphological trait in insects, affects virtually all physiological and life-history traits of an insect. Body size always shows a significant gradient change among different geographic populations of the same insect species. Many environmental factors including temperature, humidity, photoperiod, host plant, and population density contribute to this gradient change and also affect insect body size within a population. Males and females differ in their body size, a phenomenon called sexual size dimorphism (SSD). There is also geographical variation in SSD. The ways those differences formed have been comprehensively analyzed, and the formation mechanisms of these variations caused the formulation of many hypotheses, which had been proved in many insect species. In this article, we summarized the ways insect body size varies among different geographic populations, the environmental factors affecting insect body size among different geographic populations and within one population, the p