Simple Indices Provide Insight to Climate Attributes Delineating the Geographic Range of Aedes albopictus (Diptera: Culicidae) Prior to Worldwide Invasion.
Aedes albopictus (Skuse) has expanded its distribution worldwide during the past decades. Despite attempts to explain and predict its geographic occurrence, analyses of the distribution of Ae. albopictus in the context of broad climatic regions (biomes) has not been performed. We analyzed climate conditions at its distribution sites in the range before the worldwide invasions (from the easternmost Hawaii through westernmost Madagascar) by using thermal and aridity-humidity indices descriptive of major biomes. A significant advantage of this approach is that it uses simple indices clearly related to the population dynamics of Ae. albopictus. Although Ae. albopictus has been regarded as a forest species preferring humid climate, in areas with significant human habitation, the distribution sites extended from the perhumid, rain forest zone to the semiarid, steppe zone. This pattern was common from the tropics through the temperate zone. Across the distribution range, there was no seasonal discordance between temperature and precipitation; at sites where winter prevents Ae. albopictus reproduction (monthly means<10°C), precipitation was concentrated in warm months (>10°C) under the Asian summer monsoon. Absence of the species in northern and eastern coastal Australia and eastern coastal Africa was not attributable solely to climate conditions. However, Asia west of the summer monsoon range was climatically unsuitable because of low precipitation throughout the year or in warm months favorable to reproduction (concentration of precipitation in winter). We hypothesized that Ae. albopictus originated in continental Asia under the monsoon climate with distinct dry seasons and hot, wet summer, enabling rapid population growth.
Division of Parasitology, Department of Pathology and Biodefense, Faculty of Medicine, Saga University, Nabeshima 5-1-1, Saga, 849-8501, Japan (retired). motomogi@festa.ocn.ne.jp.
Motoyoshi
M
Mogi
Department of Biology, Georgetown University, 37th and O sts. NW, Washington, DC 20057.
Peter
P
Armbruster
Laboratory of Ecology, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, 920-1192, Japan.
Nobuko
N
Tuno
Instituto de Limnología Dr. Raúl A. Ringuelet, Universidad Nacional de La Plata - CONICET, CCT La Plata, Boulevard 120 y 62 - Casilla de Correo N° 712. 1900, La Plata, Buenos Aires, Argentina.
Raúl
R
Campos
Consell Comarcal del Baix Llobregat, Parc Torreblanca, 08980 Sant Feliu de Llobregat, Spain.
Roger
R
Eritja
D000330:Aedes / Q000502:physiology*; D000818:Animals; D062306:Geography, Medical; D007194:India; D007564:Japan; D008270:Madagascar; D011891:Rain; D013696:Temperature; D014329:Tropical Climate
Aedes albopictus; Culicidae; Distribution; Precipitation; Temperature