18 from subterranean breeding sites such as wells and manholes in a dengue epidemic area, Australia, and a direct epidemio- logical association between subterranean breeding sites and dengue virus infection was demonstrated [5]. In Japan, the density of Ae. albopictus was very high in catch basins which now provide important breeding sites for the species in the country [6]. Dengue viruses circulate between humans and vector mosquitoes and there is no intermediate host. Thus, spatial distribution of the vectors highly affects the epidemiology of the disease. Since DF/DHF (dengue fever/dengue hemor- rhagic fever) vaccine is unavailable for practical use, trans- mission can be prevented only by reducing human-vector contact. Therefore, many dengue control programs are conducted targeting vector mosquitoes. However, most of the programs have not achieved successful levels [7]. Case studies attribute this lack of success to (1) a shortage of per- sonnel (entomologists, social scientists, operational vector- control staff); (2) a lack of technical expertise at decentral- ized levels of service; (3) insufficient budgets; (4) inade- quate geographical coverage; (5) interventions relying mostly on insecticides; (6) difficulties in engaging communities; (7) little capacity building; (8) almost no monitoring and evaluation. From the entomological viewpoint, the lack of appropriate understanding regarding the difference in vector mosquitoes, Ae. aegypti and Ae. albopictus, is one of the major reasons for the current difficulty of control. It is well known that Ae. aegypti and Ae. albopictus have their own ecological niches and show different spatial distribution. The different spatial distribution and different ecological zones indicate that the response of the vectors to the environ- ment is different, that environmental factors influence the distribution, that infestation of Ae. aegypti and Ae. albopictus are often modified in various environments. Therefore, an understanding of the environmental factors which determine vector distribution is essential for dengue control. In the frontline of dengue control, however, measures are usually taken without critical estimation of the difference in ecology and biology between Ae. aegypti and Ae. albopictus in a given area. In spite of the co-existence of Ae. aegypti and Ae. albopictus in an area, the former species is usually targeted for control. Moreover, there have been few quanti- tative studies to elucidate how environmental and climate changes actually affect the infestation, ecology and biology of vector mosquitoes in endemic areas. In this paper, we focus on the spatial distribution of Ae. aegypti and Ae. albopictus and environmental and climate changes and review the ecological and biological difference of vectors as well as the its relation to environ- mental factors and DF/DHF. This information will be useful for future dengue control. Tropical Medicine and Health Vol.39 No.4 Supplement, 2011 VECTOR BIOLOGY In order to understand how dengue vectors are influ- enced by the environment, the general biology and ecology of Ae. aegypti and Ae. albopictus are described as follows. Aedes aegypti Although Ae. aegypti is currently distributed in urban areas throughout the tropical regions of Africa, Asia, Australia, South Pacific, Americas and some parts of the Middle East, the origin of the species is considered to be Africa [8]. According to Mattingly (1957), two subspecies are recognized morphologically. Aedes aegypti formosus has a dark body color and no pale scales on the abdominal tergite, breeds from natural habitats such as tree holes in African forests, and feeds on wild animals. This subspecies is ancestral and not anthropophilic. On the other hand, Aedes aegypti aegypti has pale scales at least on the first abdominal tergite and characteristically exhibits highly variable pale scale patterns through the first to seventh tergites. The latter is well domesticated and common around human dwellings. Sub-speciation between formosus and aegypti may have co-occurred along with domestication in the human habitat. Because of its adaptation to environments created by humans, the latter expanded its geographical distribution from the seventeenth to the nineteenth centuries via boats with water-holding vessels containing larvae. Recent genetic studies indicate that aegypti evolved from formosus in West Africa was introduced to world from that area [9]. Although their taxonomical status is still contro- versial, the domesticated form has been closely studied because of its intimate association with human and vector- borne diseases, and thus the Ae. aegypti discussed in the present paper constitutes the domesticated form. Generally, mosquitoes spend the aquatic phase in immature stages and the terrestrial phase in the adult stage during which the events of mating, blood feeding and ovipositing take place (some species are autogenous, i. e. blood feeding is not required for egg maturation and ovi- position). Among these events, larval breeding, blood feed- ing place, resting place, oviposition site and host animals differ among mosquito species. Because the biological and ecological characteristics described above are linked to degrees of human-vector contact and transmission of pathogens, studies on vector mosquitoes mainly focus on those characteristics. In the vector species, the events usually take place in the vicinity of human. It may not be an exaggeration to say that the life cycle of Ae. aegypti is completely dependent on environments created by humans. Larvae breed from a variety of artificial containers such as jars, discarded cans, flower vases, cement