Reacent distribution of Aedes albopictus in Iwate Prefecture, northern Japan and analysis of climatic conditions for northern limit of geographic distribution by geographic information systems

Abstract

It was previously reported that the northern limits of geographic distribution of Ae. albopictus in Japan are Akita and Iwate Prefectures. In this study, we carried out larval surveillance from 2009 to 2010 to clarify the present distribution of the mosquito in Iwate Prefecture and to analyze the relationship between climatic conditions and the northern distribution of Ae. albopictus by the geographic information systems (GIS). Distribution of Ae. albopictus was found in 34 collection sites from 7 cities and 2 towns in this study. Around the collection sites in Senboku 2 Chome, Morioka City where Ae. albopictus larvae were collected in 2009, an intensive investigation was carried out in 2010, and more than 20 colonies of Ae. albopictus were collected. This suggests that Ae. albopictus population has been established in Morioka City. The relationships between climatic conditions and distribution of Ae. albopictus in Iwate Prefecture were analyzed using 1 km mesh climate data from 2006 to 2010, and the following conditions were suggested for the presence of Ae. albopictus populations: >10.8°C annual mean temperature, >-1.4°C daily mean temperature in January, >185 days/year with >10.8°C mean daily temperature and >1,350 degree days of effective accumulated temperature per year.