Why does offspring size affect performance? Integrating metabolic scaling with life-history theory

Research output: Contribution to journalArticle


Within species, larger offspring typically outperform smaller offspring. While the relationship between offspring size and performance is ubiquitous, the cause of this relationship remains elusive. By linking metabolic and life-history theory, we provide a general explanation for why larger offspring perform better than smaller offspring. Using high-throughput respirometry arrays, we link metabolic rate to offspring size in two species of marine bryozoan. We found that metabolism scales allometrically with offspring size in both species: while larger offspring use absolutely more energy than smaller offspring, larger offspring use proportionally less of their maternally derived energy throughout the dependent, non-feeding phase. The increased metabolic efficiency of larger offspring while dependent on maternal investment may explain offspring size effects—larger offspring reach nutritional independence (feed for themselves) with a higher proportion of energy relative to structure than smaller offspring. These findings offer a potentially universal explanation for why larger offspring tend to perform better than smaller offspring but studies on other taxa are needed.


External organisations
  • Monash University
  • University of Queensland
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Ecology
  • Evolutionary Biology


  • Allometry, Egg size, Maternal effect
Original languageEnglish
Article number20151946
JournalProceedings of the Royal Society B: Biological Sciences
Issue number1819
Publication statusPublished - 2015 Nov 11
Publication categoryResearch
Externally publishedYes