typically produce thousands of offspring and disperse them widely, traits characteristic of r-strategists. Similarly, reptiles such as sea turtles display both r- and K-traits: although sea turtles are large organisms with long lifespans (provided they reach adulthood), they produce large numbers of unnurtured offspring. The r/K dichotomy can be re-expressed as a continuous spectrum using the economic concept of discounted future returns, with r-selection corresponding to large discount rates and K-selection corresponding to small discount rates. Ecological succession In areas of major ecological disruption or sterilisation (such as after a major volcanic eruption, as at Krakatoa or Mount St. Helens), r- and K-strategists play distinct roles in the ecological succession that regenerates the ecosystem. Because of their higher reproductive rates and ecological opportunism, primary colonisers typically are r-strategists and they are followed by a succession of increasingly competitive flora and fauna. The ability of an environment to increase energetic content, through photosynthetic capture of solar energy, increases with the increase in complex biodiversity as r species proliferate to reach a peak possible with K strategies. Eventually a new equilibrium is approached (sometimes referred to as a climax community), with r-strategists gradually being replaced by K-strategists which are more competitive and better adapted to the emerging micro-environmental characteristics of the landscape. Traditionally, biodiversity was considered maximized at this stage, with introductions of new species resulting in the replacement and local extinction of endemic species. However, the intermediate disturbance hypothesis posits that intermediate levels of disturbance in a landscape create patches at different levels of succession, promoting coexistence of colonizers and competitors at the regional scale. Application While usually applied at the level of species, r/K selection theory is also useful in studying the evolution of ecological and life history differences between subspecies, for instance the African honey bee, A. m. scutellata, and the Italian bee, A. m. ligustica. At the other end of the scale, it has also been used to study the evolutionary ecology of whole groups of organisms, such as bacteriophages. Other researchers have proposed that the evolution of human inflammatory responses is related to r/K selection. Some researchers, such as Lee Ellis, J. Philippe Rushton, and Aurelio José Figueredo, have applied r/K selection theory to various human behaviors, including crime, sexual promiscuity, fertility, IQ, and other traits related to life history theory. Rushton's work resulted in him developing "differential K theory" to attempt to explain many variations in