No abstract

The Asian longhorned tick (Haemaphysalis longicornis Neumann), native to northeast Asian regions, was recently confirmed to have invaded the USA. Although H. longicornis is a medically and economically important pest because it transmits various diseases to humans and livestock, its susceptibility to pesticides has not yet been fully investigated. Moreover, minimal genetic data on H. longicornis that could assist in its control are currently available. Therefore, in this study, to investigate the physiological response of H. longicornis to cypermethrin, a field population of H. longicornis was treated with various concentrations of cypermethrin (100–500 ppm), and the transcriptomes of a cypermethrin‐susceptible group (knock‐down at 200 ppm) and cypermethrin‐tolerant group (surviving at 500 ppm) were compared. In our analysis of the genes that were differentially expressed between the two groups of ticks, several genes involved in detoxification metabolism were upregulated in the cypermethrin‐tolerant group. Expression of genes encoding CYP450, GST, and ABC transporters were substantially higher in cypermethrin‐tolerant ticks than in the cypermethrin‐susceptible group. Given that CYP450, GST, and ABC transporters contribute to Phase I, II, and III of the detoxification metabolism process, respectively, our results suggest that H. longicornis responds physiologically to cypermethrin by altering the expression of various genes involved in detoxification metabolism, which in turn increases its tolerance to the cypermethrin.

We investigated the differences in environment of forest floor and soil characteristics between the evergreen coniferous and the temperate deciduous forests that different in dominant species in Goesan, Chungcheongbuk-Do. The accumulated litter in the deciduous forest was higher than the coniferous forest(368.3 ± 19.51 g m -2 h -1 and 405.2 ± 21.4 g m -2 h -1 ) in 2005. The decomposition rate of leaf litter were measured with litter bags and reduced across all sites 6 month after setup. the decomposition rate of leaf litter in the deciduous forest was higher than the coniferous forest(31.4% and 32.5%). The accumulated carbon of the evergreen coniferous and the temperate deciduous forests in 0~30cm soil depth were measured 81.13 t C ha -1 , 86.45 t C ha -1 respectively. Soil respiration was estimated to be 187.0 ~ 297.5 mg CO 2 m -2 h -1 in the temperate deciduous forest and 196.2 ~ 444.5 mg CO 2 m -2 h -1 in the evergreen coniferous forest, respectively. The deciduous forests was measured higher inflow and outflow of carbon (high soil carbon contents, high litterfall, high decomposition rate of litter and high soil respiration rate) than the evergreen coniferous forest.

Mosquitoes were collected biweekly from March to November for 3 years (2017)(2018)(2019) in three different habitats, including a migratory bird refuge, cowshed, and an urban area. Among a total of 22,783 female mosquitoes comprising six genera and 13 species collected for 3 years, Aedes vexans nipponii (56.08%) was the dominant species, followed by Culex pipiens complex (14.26%), Anopheles spp. (11.57%), Culex orientalis (6.90%), Aedes albopictus (4.66%), Armigeres subalbatus (4.06%), and Culex tritaeniorhynchus (1.41%); the remaining six species comprised only 1.1% of all mosquito species collected. In the three habitats, 70.42% of mosquitoes were collected in the migratory bird refuge, whereas 10.68% and 18.90% were investigated in the cowshed and urban areas, respectively. The dominant species were Ae. vexans nipponii in the migratory bird refuge, Anopheles spp. in the cowshed, and Cx. pipiens complex in the urban area. The seasonal distribution of mosquitoes showed that most were obtained between May and September, with bimodal peaks in the third week of June and third week of August. Meteorological analysis revealed a high correlation between temperature and mosquito abundance. In the flavivirus detection analysis, no virus-transmitting infectious diseases were amplified by PCR, but the Chaoyang virus was found in Ae. vexans nipponii. Considering that global warming is a major risk factor for the spread of vector-borne diseases and that mosquito has been a fatal vector of infectious disease, our study of surveillance and analysis of seasonal/environmental mosquito population dynamics are essential for public health.