Long-term trends in population biology are the domain of evolution and genetics. Whilst the way that energy is partitioned in the way that it is the domain of optimisation theory. There are a number of factors that will influence the population dynamics of animals in general. As their name implies, density-independent factors, especially meteorological factors, will act on the population irrespective of density, whilst density-dependent factors will have an increasing effect as numbers increase. The two most important factors that influence dynamics of the main African malaria vectors are rainfall and temperature. African malaria vectors often have to contend with survival through a long dry season, often with a complete absence of potential oviposition sites. Southeast Asian anophelines are physiologically adapted to humid conditions, having wider spiracles than African ones. The species may be restricted to isolated ‘refugia’ populations that expand their range during the wet season.