Evaluation of offspring size-number invariants in 12 species of lizard

T. Uller*, G. M. While, E. Wapstra, D. A. Warner, B. A. Goodman, Lin Schwarzkopf, T. Langkilde, P. Doughty, R. S. Radder, D. H. Rohr, C. M. Bull, R. Shine, M. Olsson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


The optimal division of resources into offspring size vs. number is one of the classic problems in life-history evolution. Importantly, models that take into account the discrete nature of resource division at low clutch sizes suggest that the variance in offspring size should decline with increasing clutch size according to an invariant relationship. We tested this prediction in 12 species of lizard with small clutch sizes. Contrary to expectations, not all species showed a negative relationship between variance in offspring size and clutch size, and the pattern significantly deviated from quantitative predictions in five of the 12 species. We suggest that the main limitation of current size-number models for small clutch sizes is that they rely on assumptions of hierarchical allocation strategies with independence between allocation decisions. Indeed, selection may favour alternative mechanisms of reproductive allocation that avoid suboptimal allocation imposed by the indivisible fraction at low clutch sizes.

Original languageEnglish
Pages (from-to)143-151
Number of pages9
JournalJournal of Evolutionary Biology
Issue number1
Publication statusPublished - Jan 2009
Externally publishedYes


  • life history
  • lizards
  • oviparous
  • resource allocation
  • size-number invariants
  • viviparous


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