Although the dire effects of malnourishment on an individual has
been well documented across taxa, considerably little is known if
populations can adapt to chronic malnutrition over several generations,
the adaptive traits that facilitate such tolerance and the associated
trade-offs. We used an experimental evolution approach involving replicate
populations of Drosophila melanogaster (over 190 generations) to
investigate the life-history and behavioural consequences of adaptation to
larval malnutrition. We found that the ability to cope with malnutrition
leads to several adaptations that impinge upon diverse aspects of
structure, function and life-history of the fly. However, this
malnutrition tolerance is costly, increasing susceptibility to intestinal
pathogens and reducing fecundity. Interestingly, this investigation also
led to the discovery and detailed study of two novel larval behaviours:
predatory larval cannibalism and prepupal tunnel building. Furthermore,
these experimentally evolved populations have raised important questions
on the evolution and maintenance of traits that regulate nutritional
homeostasis in an organism.