Objective To investigate the current status of resistance to commonly used insecticides in Aedes albopictus in Xingyi and Chishui cities of Guizhou province, China, to explore the killing effect of Bacillus thuringiensis subsp. israelensis on Ae. albopictus larvae in Chishui, and to provide a scientific basis for the prevention and control of Aedes vector and related infectious diseases. Methods In September 2018 and July 2019, Ae. albopictus larvae were collected from small water containers in communities in different locations of Xingyi and Chishui and were reared to obtain the F1 to F2 generations in the laboratory. The larval dipping method and the contact tube method recommended by WHO were used to investigate the insecticide resistance of Ae. albopictus larvae and adults, respectively, and determine the degree of insecticide resistance. Results The resistance ratios of Ae. albopictus larvae against deltamethrin, beta-cypermethrin, permethrin, and DDVP were 44.78, 39.18, 113.74, and 2.74 folds, respectively, in Xingyi city, and 38.38, 24.25, 26.37, and 1.64 folds, respectively, in Chishui city. In addition, the resistance ratios of Ae. albopictus larvae against propoxur and B. thuringiensis subsp. israelensis were 7.51 and 1.28 folds, respectively, in Chishui. The 24-hour mortality rates of adult Ae. albopictus mosquitoes in Xingyi against deltamethrin, beta-cypermethrin, permethrin, and fenitrothion were 27.22%, 57.89%, 46.75%, and 100%, respectively. The 24-hour mortality rates of adult mosquitoes in Chishui against deltamethrin, beta-cypermethrin, and permethrin were 53.00%, 93.33%, and 94.40%, respectively, and the mortality rate against propoxur was 99.20%. Conclusion Ae. albopictus larvae in both cities have developed moderate or above resistance to pyrethroid insecticides and are sensitive to DDVP. Ae. albopictus larvae from Chishui have low resistance to propoxur and are sensitive to B. thuringiensis subsp. israelensis. In both Xingyi and Chishui cities, Ae. albopictus adults have resistance or suspected resistance to pyrethroid insecticides and are sensitive to fenitrothion or propoxur. It is recommended to adhere to the principle of integrated vector management in both cities, timely monitor the level and changing trend of insecticide resistance of Ae. albopictus, suspend the use of high-resistance insecticides, and adopt an appropriate rotation or combination strategy, so as to delay the development of insecticide resistance.

In order to investigate the biodiversity of gamasid mites in Yongxing Island of Sansha in Hainan province, China, gamasid mite specimens were collected in the soil around Yongxing Island in 2017. According to morphological taxonomy, there were four newly recorded species of gamasid mites in Hainan province, i.e., Stratiolaelaps scimitus (Womersley, 1956), Gymnolaelaps weishanensis (Gu & Guo, 1997), Cosmolaelaps hrdyi (Samšiňák, 1961), and Parasitus wentinghuani (Ma, 1995). The specimens are deposited in Laboratory of Systematic and Applied Acarology, Shandong Agricultural University.

【Abstract】 Objective To investigate the geographical distribution, habitat, dominant hosts and population spatial distribution patterns of Ornithonyssus bacoti in Yunnan province.  Methods   A total of 28 counties in five zoogeographical sub?regions were chosen as the investigated sites. Each investigated site was divided into two habitats (indoors and outdoors) and then small mammal hosts were randomly captured by mouse traps. All the gamasid mites from the body surface of the hosts were collected and preserved in 70% ethanol. Hoyer’s medium was used to mount the mites onto glass slides and each mite specimen was finally identified by microscope. The spatial pattern of the mite was analyzed by K?value of negative binomial distribution, patchiness index, Taylor’s power function and Iwao’s model.  Results A total of 3339 O. bacoti were collected from 11 560 captured  small  mammal  hosts  which belonged to 3 orders 4 families 8 genera  and  15  species.  Of  the  investigated 28 counties, O. bacoti was found in 21 counties and the mites were collected from 15 species of small mammal hosts. O.bacoti mainly distributed in Southwest region (accounted for 90% of the total), and the quantity of O. bacoti in indoors (2914, 87.27%) were obviously higher than that in outdoors (425, 12.73%).  90% mites mainly parasitized on the body surface of Rattus norvegicus and R. tanezumi which were  the  dominant  host  of  mites.  The  results  showed  that  the  spatial  pattern  of  O. bacoti  was  an  aggregated  distribution. Conclusion O. bacoti  widely  distributes  in  Yunnan  province  and  mainly  parasitizes  on  the  body surface of R. norvegicus and R. tanezumi. It is of aggregated distribution among its main hosts.