Sexual size dimorphism requires a corresponding sex difference in development time: a meta-analysis in insects
Article first published online: 15 OCT 2013
© 2013 The Author. Functional Ecology © 2013 British Ecological Society
How to Cite
Teder, T. (2013), Sexual size dimorphism requires a corresponding sex difference in development time: a meta-analysis in insects. Functional Ecology. doi: 10.1111/1365-2435.12172
- Article first published online: 15 OCT 2013
- Accepted manuscript online: 21 AUG 2013 08:56AM EST
- Manuscript Accepted: 18 JUL 2013
- Manuscript Received: 4 DEC 2012
- Estonian Science Foundation. Grant Number: 8413
- Estonian Ministry of Education and Science. Grant Number: SF0180122s08
- EU through the European Regional Development Fund
- fecundity selection;
- life-history trade-off;
- sexual bimaturism;
- sexual selection;
- sexual size dimorphism
- The degree and direction of sexual size dimorphism (SSD) vary greatly between animal species. At the ontogenetic level, SSD may result from sex differences in birth size, growth rate and/or development time. Nevertheless, evidence concerning proximate causation of SSD is scattered, and the data used to infer ontogenetic determinants of SSD have not always been appropriate for this purpose.
- I use a comprehensive literature-derived data base of relevant sex-specific traits on 169 species to address the significance of sex differences in larval development time (SDTD) as a proximate source of SSD in insects.
- In a clear majority of species (79%), SSD and SDTD were qualitatively congruent, that is, the larger sex had also a longer larval development. In strongly size-dimorphic species, the qualitative correspondence between SSD and SDTD was nearly universal. Consistently, in a phylogenetically diverse array of insect clades, SDTD increased with increasing SSD across species.
- The results indicate that the evolution and maintenance of high SSD values are rarely possible without a prolonged development of the larger sex.
- The role of sex differences in growth rate as the ontogenetic determinant of SSD in insects requires further studies that should ideally be based on detailed monitoring of larval growth schedules.
- The increase in SDTD with increasing SSD is consistent with the idea that the widespread phenomenon of protandry (the emergence of male adults before females) may not be selected for per se, but rather may primarily be an incidental by-product of other selection pressures.