Urbanization increases Aedes albopictus larval habitats and accelerates mosquito development and survivorship, according to a study by Dr. Xiaoguang Chen's group from the School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, China, published in PLOS Neglected Tropical Diseases.
Ae. albopictus is one of the most invasive species and important vectors of dengue fever, chikungunya disease, and yellow fever in many countries. Vector biology and mosquito borne diseases are strongly affected by environmental changes. Urbanization is a worldwide trend and is one of the most ecologically modifying phenomena.
The purpose of this study was to determine how environmental changes due to urbanization affect the biology of Ae. albopictus. Aquatic habitats and Ae. albopictus larval population surveys were conducted from May to November 2013 in three areas representing rural, suburban, and urban settings in Guangzhou, China. Ae. albopictus adults were collected monthly using BG-Sentinel traps. Ae. albopictus larva and adult life-table experiments were conducted with 20 replicates in each of the three study areas.
The urban area had the highest and the rural area had the lowest number of aquatic habitats that tested positive for Ae. albopictus larvae. Densities in the larval stages varied among the areas, but the urban area had almost two fold higher densities in pupae and three-fold higher in adult populations compared with the suburban and rural areas. Larvae developed faster and the adult emergence rate was higher in the urban area than in suburban and rural areas. The survival time of adult mosquitoes was also longer in the urban area than it was in suburban and rural areas.
The researchers concluded that Urbanization substantially increased the density, larval development rate, and adult survival time of Ae. albopictus, which in turn potentially increased the vector capacity, and therefore, disease transmissibility.