Evolutionary Ecology

, Volume 23, Issue 3, pp 425–433 | Cite as

A test of Rensch’s rule in dwarf chameleons (Bradypodion spp.), a group with female-biased sexual size dimorphism

  • Devi Stuart-Fox
Original Paper


Rensch’s rule describes a pattern of allometry in sexual size dimorphism (SSD): when males are the larger sex (male-biased SSD), SSD increases with increasing body size, and when females are the larger sex (female-biased SSD), SSD decreases with increasing body size. While this expectation generally holds for taxa with male-biased or mixed SSD, examples of allometry for SSD consistent with Rensch’s rule in groups with primarily female-biased SSD are remarkably rare. Here, I show that the majority of dwarf chameleons (Bradypodion spp.) have female-biased SSD. In accordance with Rensch’s rule, the group exhibits an allometric slope of log(female size) on log(male size) less than one, although statistical significance is dependent on the phylogenetic comparative method used. In this system, this pattern is likely due to natural selection on both male and female body size, combined with fecundity selection on female body size. In addition to quantifying SSD and testing Rensch’s rule in dwarf chameleons, I discuss reasons why Rensch’s rule may only rarely apply to taxa with female-biased SSD.


Allometry Allometric scaling Body size Comparative method Fecundity selection Natural selection Phylogenetic Sexual selection 



I am grateful to Adnan Moussalli for field assistance and critical comments on the manuscript and to Martin Whiting for facilitating this research. Funding was from a National Research Foundation (NRF) grant to DSF. Permits: MPB.5104 (Mpumalanga), 005-00001 (Limpopo), 1721/2003 and 4390/2005 (KZN), 234/2003 (Western Cape), WRO 11/03 WR (Eastern Cape).


  1. Abouheif E, Fairbairn DJ (1997) A comparative analysis of allometry for sexual size dimorphism: Assessing Rensch’s rule. Am Nat 149:540–562CrossRefGoogle Scholar
  2. Blanckenhorn WU, Dixon AFG, Fairbairn DJ, Foellmer MW, Gibert P, van der Linde K, Meier R, Nylin S, Pitnick S, Schoff C, Signorelli M, Teder T, Wiklund C (2007) Proximate causes of Rensch’s rule: does sexual size dimorphism in arthropods result from sex differences in development time? Am Nat 169:245–257PubMedCrossRefGoogle Scholar
  3. Branch WR (1998) A field guide to snakes and other reptiles of southern Africa 3rd edn. Struik Publishers, Cape TownGoogle Scholar
  4. Burrage BR (1973) Comparative ecology and behaviour of Chamaeleo pumilis pumilis (Gmelin) and C. namaquensis A. Smith (Sauria: Chamaeleonidae). Ann S Afr Mus 61:1–158Google Scholar
  5. Butler MA, Schoener TW, Losos JB (2000) The relationship between sexual size dimorphism and habitat use in Greater Antillean Anolis Lizards. Evolution 54:259–272PubMedGoogle Scholar
  6. Colwell RK (2000) Rensch’s rule crosses the line: Convergent allometry of sexual size dimorphism in hummingbirds and flower mites. Am Nat 156:495–510CrossRefGoogle Scholar
  7. Diaz-Uriarte R, Garland T (1996) Testing hypotheses of correlated evolution using phylogenetically independent contrasts: Sensitivity to deviations from Brownian motion. Syst Biol 45:27–47CrossRefGoogle Scholar
  8. Fairbairn DJ (1997) Allometry for sexual size dimorphism: pattern and process in the coevolution of body size in males and females. Annu Rev Ecol Syst 28:659–687CrossRefGoogle Scholar
  9. Fairbairn DJ (2005) Allometry for sexual size dimorphism: testing two hypotheses for Rensch’s rule in the water strider Aquarius remigis. Am Nat 166:S69–S84PubMedCrossRefGoogle Scholar
  10. Felsenstein J (1985) Phylogenies and the comparative method. Am Nat 125:1–15CrossRefGoogle Scholar
  11. Garland TJ, Harvey PH, Ives AR (1992) Procedures for the analysis of comparative data using phylogenetically independent contrasts. Syst Biol 41:18–32Google Scholar
  12. Hansen TF (1997) Stabilizing selection and the comparative analysis of adaptation. Evolution 51:1341–1351CrossRefGoogle Scholar
  13. Jacobsen NHG (1989) A herpetological survey of the Transvaal. School of Life and Environmental Sciences, University of Natal, DurbanGoogle Scholar
  14. Jannot JE, Kerans BL (2003) Body size, sexual size dimorphism, and Rensch’s rule in adult hydropsychid caddisflies (Trichoptera : Hydropsychidae). Can J Zool 81:1956–1964CrossRefGoogle Scholar
  15. Kratochvil L, Frynta D (2002) Body size, male combat and the evolution of sexual dimorphism in eublepharid geckos (Squamata: Eublepharidae). Biol J Linn Soc 76:303–314CrossRefGoogle Scholar
  16. Martins EP (2004) COMPARE 4.6: statistical analysis of comparative data. pp. Available free from Dept. of Biology, Indiana University, Bloomington
  17. Martins EP, Hansen TF (1997) Phylogenies and the comparative method: a general approach to incorporating phylogenetic information into the analysis of interspecific data. Am Nat 149:646–667CrossRefGoogle Scholar
  18. Martins EP, Diniz JAF, Housworth EA (2002) Adaptive constraints and the phylogenetic comparative method: a computer simulation test. Evolution 56:1–13PubMedGoogle Scholar
  19. Martins EP, Labra A, Halloy M, Thompson JT (2004) Large-scale patterns of signal evolution: an interspecific study of Liolaemus lizard headbob displays. Anim Behav 68:453–463CrossRefGoogle Scholar
  20. Nečas P (2001) Chameleons: Nature’s Hidden Jewels. Krieger Publishing, MalabarGoogle Scholar
  21. Olsson M, Madsen T (1995) Female choice on male quantitative traits in lizards—why is it so rare? Behav Ecol Sociobiol 36:179–184CrossRefGoogle Scholar
  22. Raihani G, Szekely T, Serrano-Meneses MA, Pitra C, Goriup P (2006) The influence of sexual selection and male agility on sexual size dimorphism in bustards (Otididae). Anim Behav 71:833–838CrossRefGoogle Scholar
  23. Rensch B (1960) Evolution above the species level. Columbia University Press, New YorkGoogle Scholar
  24. Shine R (1989) Ecological causes for the evolution of sexual size dimorphism. Quart Rev Biol 64:419–443PubMedCrossRefGoogle Scholar
  25. Stuart-Fox D, Moussalli A (2007) Sex-specific ecomorphological variation and the evolution of sexual dimorphism in dwarf chameleons (Bradypodion spp.). J Evol Biol 20:1073–1081PubMedCrossRefGoogle Scholar
  26. Stuart-Fox DM, Whiting MJ (2005) Male dwarf chameleons assess risk of courting large, aggressive females. Biol Lett 1:231–234PubMedCrossRefGoogle Scholar
  27. Stuart-Fox D, Moussalli A, Whiting MJ (2007) Natural selection on social signals: signal efficacy and the evolution of chameleon display coloration. Am Nat 170:916–930PubMedCrossRefGoogle Scholar
  28. Stuart-Fox DM, Firth D, Moussalli A, Whiting MJ (2006) Multiple traits in chameleon contests: designing and analysing animal contests as a tournament. Anim Behav 71:1263–1271CrossRefGoogle Scholar
  29. Szekely T, Freckleton RP, Reynolds JD (2004) Sexual selection explains Rensch’s rule of size dimorphism in shorebirds. Proc Natl Acad Sci USA 101:12224–12227PubMedCrossRefGoogle Scholar
  30. Tolley KA, Tilbury C, Branch WR, Matthee CA (2004) Phylogenetics of the southern African dwarf chameleons, Bradypodion (Squamata: Chamaeleonidae). Mol Phylogenet Evol 30:354–365PubMedCrossRefGoogle Scholar
  31. Tolley KA, Burger M, Turner AA, Matthee CA (2006) Biogeographic patterns and phylogeography of dwarf chameleons (Bradypodion) in an African biodiversity hotspot. Mol Ecol 15:781–793PubMedCrossRefGoogle Scholar
  32. Tubaro PL, Bertelli S (2003) Female-biased sexual size dimorphism in tinamous: a comparative test fails to support Rensch’s rule. Biol J Linn Soc 80:519–527CrossRefGoogle Scholar
  33. Vitousek MN, Mitchell MA, Woakes AJ, Niemack MD, Wikelski M (2007) High costs of female choice in a lekking lizard. PLoS One 2:e567PubMedCrossRefGoogle Scholar
  34. Young KA (2005) Life-history variation and allometry for sexual size dimorphism in Pacific salmon and trout. Proc R Soc Lond B 272:167–172CrossRefGoogle Scholar
  35. Zamudio KR (1998) The evolution of female-biased sexual size dimorphism: a population-level comparative study in horned lizards (Phrynosoma). Evolution 52:1821–1833CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  1. 1.School of Animal, Plant and Environmental SciencesUniversity of the WitwatersrandJohannesburgSouth Africa
  2. 2.Department of ZoologyUniversity of MelbourneMelbourneAustralia

Personalised recommendations