Rensch's rule

Rensch's rule is an allometric law concerning the relationship between the extent of sexual size dimorphism (SSD) and which sex is larger. Across species within a lineage, size dimorphism will increase with increasing body size when the male is the larger sex, and decrease with increasing average body size when the female is the larger sex.

Examples of phylogenetic lineages that appear to follow this rule include primates, pinnipeds, and artiodactyls.^[1]

It was proposed by Bernhard Rensch in 1950.^[2]

References

↑ Fairbairn, D.J. (1997). "Allometry for Sexual Size Dimorphism: Pattern and Process in the Coevolution of Body Size in Males and Females". Annu. Rev. Ecol. Syst. 28 (1): 659–687. doi:10.1146/annurev.ecolsys.28.1.659.
↑ Rensch, B. (1950). Die Abhangigkeit der relativen Sexualdifferenz von der Korpergrosse. Bonner Zoologische Beitrage 1:58-69.

Biological rules

Allen's rule (Populations have shorter appendages in colder climates)
Bergmann's rule (Populations have larger bodies in colder climates)
Cope's rule (Organisms within a population get larger over time)
Foster's rule (Small species get larger and large species smaller after colonizing islands)
Gloger's rule (Populations have lighter colouration in colder, drier climates)
Haldane's rule (Hybrid sexes that are absent, rare, or sterile, are heterozygous)
Rapoport's rule (latitudinal range increases with latitude)
Rensch's rule (Sexual size dimorphism increases with size when males are larger, and decreases with size when females are larger)
Thorson's rule (Number of eggs of benthic marine invertebrates decreases with latitude)