Abstract
In holometabolus insects, fitness is intricately linked with body size. Large males with high energy reserves often adopt ‘live fast, die young’ life-history strategy to maximize fitness compared to small individuals. However, in promiscuous, iteroparous systems, males that live fast and die late have evolutionary advantage. Using two types of Drosophila melanogaster populations- one that have evolved small size as a response to long term selection for faster development and extended longevity (FLJs) and the other that are large ancestral control populations (JBs), we revisit the (i) disposable soma theory, and (ii) live fast, die early life history strategy hypothesis. Contrary to the two hypotheses, the small FLJ males with significantly reduced energy reserves invested heavily in pre-reproductive traits as indicated by significantly higher courtship duration, number of mounting attempts, and comparable copulation duration to JB males. FLJ males also have comparable lifetime fecundity and realized fitness without compromising on longevity, suggesting that FLJ males are adopting a novel “live fast, die late” life history strategy.