Variation in the microbiota across different developmental stages of Aedes albopictus is affected by ampicillin exposure.

The microbiota plays an important role in the growth of mosquitoes and the transmission of mosquito-borne pathogens. The effects of changes in aquatic habitats in which mosquitoes live, as one of the major factors closely associated with the microbial communities of mosquitoes, on the microbiota of different developmental stages remain to be elucidated. Here, we compared the microbiota of larvae and pupae of Aedes albopictus exposed to different ampicillin concentrations and investigated the bacterial composition of adult females. The results demonstrate that the microbial community differed substantially between developmental stages and that samples of the same stages shared similarities, whereas differences were observed between adult females. Based on all observations, we hypothesize that the use of ampicillin caused dysbiosis rather than excluding bacteria from mosquitoes and that the disturbing effect of ampicillin was obvious in adults. Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that most of the bacteria identified in this study were significantly associated with metabolism. Taken together, our results indicate that ampicillin can change the abundance of bacteria, while microbial communities of Ae. albopictus showed obvious stage-specific characteristics. Further investigations are needed to characterize specific bacterial components that are affected by ampicillin exposure and to quantify their functions, thereby providing a better understanding of the influence of antibiotics on microbial communities at different life stages.

A Survey of Insecticide Resistance in Aedes albopictus (Diptera: Culicidae) During a 2014 Dengue Fever Outbreak in Guangzhou, China.

A dengue fever outbreak in Guangzhou, Guangdong Province, China, in 2014 resulted in ∼37,000 cases and five deaths. Insecticides were sprayed to control the vector of this outbreak, Aedes albopictus (Skuse), a species of mosquito. Aedes albopictus specimens collected from Huadu District (HD), Huangpu District (HP), Luogang District (LG), and Nansha District (NS) in Guangzhou were evaluated using WHO-recommended bioassays for both larvae and adult mosquitoes to determine population resistance to deltamethrin, beta-cypermethrin, cypermethrin, permethrin, dichlorvos, temephos, propoxur, and DDT. Compared with a susceptible laboratory strain of Ae. albopictus (S-lab), all populations showed decreased sensitivities to the eight insecticides, with resistance ratios (RRs) ranging from 2.2 to 275. The RRs were 6.8-275 for pyrethroids, 2.2-4.4 for organophosphates, 5.7-9.0 for carbamates, and 5.3-94.3 for organochlorines. For adult mosquitoes, all populations were sensitive to dichlorvos with 100% mortalities. Mosquitoes from HP, LG, and NS were also sensitive to propoxur. But for other tested insecticides, different degrees of resistance (mortality rate ranging from 11.7% to 94.7%) were observed. Among the four field populations, the resistance levels are presented as follows in descending order: HP > HD > NS > LG. The levels among insecticides classes were pyrethroids > organochlorines > carbamates > organophosphates.

Influence of Bloodmeal Host on Blood Feeding, Egg Production, and Offspring Sex Ratio of Ctenocephalides felis felis (Siphonaptera: Pulicidae).

The cat flea, Ctenocephalides felis felis (Bouché), feeds on different host species, causing annoyance or transmitting disease agents. In this study, the influence of the host of the cat flea on blood feeding, egg production, and sex ratio of the offspring was investigated. Two strains of C. felis were domesticated on either rats or mice for >10 yr in the laboratory, and in this study, these fleas were placed in the following groups and fed on rats or mice continuously: Group A (rat-domesticated C. felis with rats as host); Group B (rat-domesticated C. felis with mice as host); Group C (mouse-domesticated C. felis with rats as host); and Group D (mouse-domesticated C. felis with mice as host). In total, 240 adult fleas were in each group at a sex ratio of female:male = 1.7:1. The mean egg production per flea of Groups A, B, C, and D was 55.0, 19.2, 62.5, and 13.2, respectively. A significant correlation between egg production and the volume of blood consumed was detected for Groups A, B, C, and D. The sex ratio (F:M) of the offspring in Groups A and C was 2.07 and 2.11, respectively, whereas in Groups B and D, the ratio was 1.04 and 1.03, respectively. In conclusion, the C. felis with rats as host consumed more blood, produced more eggs, and had higher sex ratios of the offspring than those with mice as the host.

Permanent genetic resources added to Molecular Ecology Resources Database 1 June 2012-31 July 2012.

This article documents the addition of 96 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Clarias batrachus, Marmota himalayana, Schizothorax richardsonii, Sitophilus zeamais and Syagrus romanzoffiana. These loci were cross-tested on the following species: Clarias dussumeri, Clarias gariepinus, Heteropneustus fossilis, Sitophilus granarius and Sitophilus oryzae.