The study assessed the distribution of Malaysian Ae. albopictus adults associated with Wolbachia detection in low-rise residential areas using a modified sticky ovitrap (MSO). The relationship between Ae. albopictus and climatological parameters were also determined. Fifty-two weeks of surveillance using 273 MSOs were conducted in four installation areas of eleven sampling sites. Specimens were subjected to PCR using wsp-specific primers for Wolbachia detection. The relationship between climatological parameters and Ae. albopictus captured were analyzed using Spearman rank correlation coefficient test. The majority of Ae. albopictus were captured in residential houses (87%), followed by playgrounds or parks (11.5%), guardhouses (1%), and community halls (0.5%). Most of the specimens (92%) were superinfected with wAlbA and wAlbB strains. A positive correlation with no significant association was found for rainfall (r = 0.015, P = 0.072), relative humidity (r = 0.005, P = 0.526), minimum temperature (r = 0.005, P = 0.516), and mean temperature (r = 0.003, P = 0.689). MSO effectively captured a high number of Ae. albopictus that was determined to be the predominant mosquito species found in low-rise residential areas. The adult collection is not only influenced by climatological parameters but also by other factors, including environmental conditions and general sanitation status.
The fundamental approach to the biological control of Aedes albopictus requires the mass rearing of mosquitoes and the release of highly competitive adults in the field. As the fitness of adults is highly dependent on the development of immatures, we aimed to identify the minimum feeding regime required to produce viable and competitive adults by evaluating three response parameters: development duration, immature mortality, and adult wing length. Our study suggests at least 0.60 mg/larva/day of larval diet composed of dog food, dried beef liver, yeast, and milk powder in a weight ratio of 2:1:1:1 is required to maximize adult fitness. With standardized protocols in mass rearing, intensive studies can be readily conducted on mosquito colonies to facilitate comparisons across laboratories. This study also evaluated the differences in response of laboratory and field strains under different feeding regimes. We found that strain alone did not exert substantial effects on all response parameters. However, the field strain exhibited significantly lower immature mortality than the laboratory strain under the minimum feeding regime. Females and males of the laboratory strain had longer wing lengths under nutritional constraint due to the higher mortality that resulted in reduced interactions with the remaining larvae. Meanwhile, the field strain exhibited heterogeneous duration of immature development compared with the laboratory strain. The disparities demonstrated by the two strains in this study suggest the effect of inbreeding surfaced after a long term of laboratory colonization. Despite the trade-offs resulting from laboratory colonization, the competitiveness of the laboratory strain of Ae. albopictus is comparable to the field strain, provided the larvae are fed optimally.
We investigated spatial autocorrelation of female Aedes aegypti L. mosquito abundance from BG-Sentinel trap and sticky ovitrap collections in Cairns, north Queensland, Australia. BG-Sentinel trap collections in 2010 show a significant spatial autocorrelation across the study site and over a smaller spatial extent, while sticky ovitrap collections only indicate a non-significant, weak spatial autocorrelation. The BG-Sentinel trap collections were suitable for spatial interpolation using ordinary kriging and cokriging techniques. The uses of Premise Condition Index and potential breeding container data have helped improve our prediction of vector abundance. Semiovariograms and prediction maps indicate that the spatial autocorrelation of mosquito abundance determined by BG-Sentinel traps extends farther compared to sticky ovitrap collections. Based on our data, fewer BG-Sentinel traps are required to represent vector abundance at a series of houses compared to sticky ovitraps. A lack of spatial structure was observed following vector control treatment in the area. This finding has implications for the design and costs of dengue vector surveillance programs.