Resistance to pyrethroids and the relationship between adult resistance and knockdown resistance (kdr) mutations in Aedes albopictus in dengue surveillance areas of Guizhou Province, China.

The Ae. albopictus mosquito has gained global attention due to its ability to transmit viruses, including the dengue and zika. Mosquito control is the only effective way to manage dengue fever, as no effective treatments or vaccines are available. Insecticides are highly effective in controlling mosquito densities, which reduces the chances of virus transmission. However, Ae. albopictus has developed resistance to pyrethroids in several provinces in China. Pyrethroids target the voltage-gated sodium channel gene (VGSC), and mutations in this gene may result in knockdown resistance (kdr). Correlation studies between resistance and mutations can assist viruses in managing Ae. albopictus, which has not been studied in Guizhou province. Nine field populations of Ae. albopictus at the larval stage were collected from Guizhou Province in 2022 and reared to F1 to F2 generations. Resistance bioassays were conducted against permethrin, beta-cypermethrin, and deltamethrin for both larvae and adults of Ae. albopictus. Kdr mutations were characterized by PCR and sequencing. Additionally, the correlation between the kdr allele and pyrethroid resistance was analyzed. All nine populations of Ae. albopictus larvae and adults were found to be resistant to three pyrethroid insecticides. One kdr mutant allele at codon 1016, one at 1532 and three at 1534 were identified with frequencies of 13.86% (V1016G), 0.53% (I1532T), 58.02% (F1534S), 11.69% (F1534C), 0.06% (F1534L) and 0.99% (F1534P), respectively. Both V1016G and F1534S mutation mosquitoes were found in all populations. The kdr mutation F1534S was positively correlated with three pyrethroid resistance phenotypes (OR > 1, P < 0.05), V1016G with deltamethrin and beta-cypermethrin resistance (OR > 1, P < 0.05) and F1534C only with beta-cypermethrin resistance (OR > 1, P < 0.05). Current susceptibility status of wild populations of Ae. albopictus to insecticides and a higher frequency of kdr mutations from dengue-monitored areas in Guizhou Province are reported in this paper. Outcomes of this study can serve as data support for further research and development of effective insecticidal interventions against Ae. albopictus populations in Guizhou Province.

Two new species of the genus Nigrobaetis Kazlauskas (in Novikova & Kluge), 1987 (Ephemeroptera: Baetidae) from Southwest China.

Two new species of Nigrobaetis Kazlauskas (in Novikova & Kluge), 1987 are described from Southwest China: Nigrobaetis bilongus sp. nov. based on larval and imaginal materials which are reared from larvae; Nigrobaetis trialbus sp. nov. based on larval stage.

First record of hygropetric species in the genus Paegniodes Eaton, 1881 (Ephemeroptera: Heptageniidae) with description of a new species from China.

Paegniodes oligopilus sp. nov., a first hygropetric species in the genus Paegniodes Eaton, 1881 found from madicolous habitat, is described based on larvae from Southwest China. The new species is characterized by the posterior margin of 1st segment bearing a row of 13-15 stout setae; mesonotum and abdominal tergites II-IX having a reddish brown median stripe; swimming setae of cerci and median caudal filament are vestigial. The morphological affinities and feeding habits with other known species are discussed.

Genus Bungona Harker, 1957 (Ephemeroptera: Baetidae) from China, with descriptions of three new species and a key to Oriental species.

Six species of Bungona Harker, including three species of the subgenus Centroptella Braasch Soldán and three species of subgenus of Chopralla Waltz McCafferty, are reported from China. Of which, three new species, Bungona (Centroptella) ovata sp. nov., Bungona (Centroptella) quadrata sp. nov. and Bungona (Chopralla) bifida sp. nov., are described based on nymphal materials. In addition, Bungona (Chopralla) liebenauae (Soldán, Braasch Muu, 1987) that was previously known only from Vietnam is newly recorded in China. An identification key to Bungona species known from Oriental Region is presented.

Taxonomic notes on the genus Baetiella Uéno from China, with the descriptions of three new species (Ephemeroptera: Baetidae).

Nine Baetiella species, including three new species, are reported from China. Baetiella lanpingensis n. sp. is diagnosed by the 2nd segment of labial palpus without inner-apical lobe, the posteromedian margin of terga I-VI each with a single protuberance, posterior margin of sterna V-IX each with a row of continuous long spatulate setae and median caudal filament with only one segment. Baetiella sexta n. sp. is characterized by the 2nd segment of labial palpus bearing an inner-apical lobe, the posteromedian margins of terga I-VI each with a single protuberance, posterior margins of sterna I-VII smooth and median caudal filament with 3-5 segments. Baetiella spathae n. sp. is distinguished from its congeners by the terminal segment of labial palpus asymmetric coniform, the posteromedian margin of terga I-IX each with a single protuberance and posterior margin of sterna V-IX each with a row of long spatulate setae. Additionally, B. macani (Müller-Liebenau, 1985) is removed from the synonymy with B. bispinosa (Gose, 1980) and considered as a valid species. B. marginata Braasch, 1983 is recorded for the first time from China. A key to fourteen species of Baetiella known from mature nymphal stages in the world is provided.

First record of the genus Gratia Thomas (Ephemeroptera, Baetidae) from China with the description of a new species.

A new species of Baetidae, Gratiabaibungensis sp. n., is described and illustrated based on nymphal stage collected from the southeastern Tibet (Xizang) and the genus is reported for the first time from China. This new species can be readily differentiated from its congeners by the absence of a protuberance on the posterior margin of the abdominal tergum X, glabrate simple submarginal setae on the labrum, and the posterior margin of sterna VI-IX having much longer spatulate setae.

The genus Labiobaetis (Ephemeroptera: Baetidae) in China, with description of a new species.

Five species of the genus Labiobaetis (Baetidae) are recognized from China based on mature nymphs, including a new species, Labiobaetis ancoralis n. sp. and a new combination, Labiobaetis mustus (Kang & Yang) n. comb. The new species differs from L. multus (Müller-Liebenau) and L. pulchellus (Müller-Liebenau & Hubbard) by the spatulate submarginal setae on labrum and the apical segment of maxillary palpus with a pronounced excavation near apex. Imago stage of L. mustus (Kang & Yang) n. comb. is described for the first time based on male and female imagoes reared from nymphs, which can be distinguished from other known imagoes of Labiobaetis by the color pattern of abdominal terga and hind wing having a tiny vestigial costal process. All Oriental species previously transferred to Pseudocloeon are reassigned to Labiobaetis in the present paper. An identification key is provided to the known mature nymphs of Oriental Labiobaetis species.

Genetic k-means clustering approach for mapping human vulnerability to chemical hazards in the industrialized city: a case study of Shanghai, China.

Reducing human vulnerability to chemical hazards in the industrialized city is a matter of great urgency. Vulnerability mapping is an alternative approach for providing vulnerability-reducing interventions in a region. This study presents a method for mapping human vulnerability to chemical hazards by using clustering analysis for effective vulnerability reduction. Taking the city of Shanghai as the study area, we measure human exposure to chemical hazards by using the proximity model with additionally considering the toxicity of hazardous substances, and capture the sensitivity and coping capacity with corresponding indicators. We perform an improved k-means clustering approach on the basis of genetic algorithm by using a 500 m × 500 m geographical grid as basic spatial unit. The sum of squared errors and silhouette coefficient are combined to measure the quality of clustering and to determine the optimal clustering number. Clustering result reveals a set of six typical human vulnerability patterns that show distinct vulnerability dimension combinations. The vulnerability mapping of the study area reflects cluster-specific vulnerability characteristics and their spatial distribution. Finally, we suggest specific points that can provide new insights in rationally allocating the limited funds for the vulnerability reduction of each cluster.

A new species of Prosopistoma (Ephemeroptera: Prosopistomatidae) from China with a key to Oriental species.

A new species of the monogeneric family Prosopistomatidae, Prosopistoma ocellatum sp. n., is described and illustrated based on mature larval stages from Guangxi and Hainan, southern China. The new species can be readily distinguished from the other members of Prosopistoma by the following combination of characters: antenna 6-segmented, segment III much longer than segments IV-VI; three bristles at the base of the inner canine; 10-11 pectinate setae on ventral margin of fore tibiae, ventral and basal half surface of all femora with dense scale-like structures, and color pattern of eye-spot on the mesonotum. An update key to the known Oriental species is provided.