Laboratory studies of density-dependent selection: Adaptations to crowding in Drosophila melanogaster

Over the last decade or so, studies on replicated sets of Drosophila populations, subjected to life-stage-specific density-dependent natural selection in the laboratory, have greatly enhanced and refined our understanding regarding how these organisms adapt to crowded conditions, Fundamental trade offs constraining the evolution of life-histories under crowded conditions have been uncovered such as the negative association between efficiency of food acquisition and its subsequent utilization. A large suite of traits adaptive under crowded culture conditions has been identified, and the behavioural and physiological mechanisms underlying adaptation to crowding are becoming understood, These studies have yielded results that are sometimes at odds with well-established theoretical principles and have, thus, also led to a refinement of our theoretical understanding of how density-dependent selection can shape the life histories of organisms.