Are weapon allometries steeper in major or minor males? A meta-analysis.

This article focuses on the influence of metamorphosis type on the allometric scaling of sexually selected weapons in male-dimorphic terrestrial arthropods. Through a phylogenetically controlled meta-analysis of 59 effect sizes from 50 species across five orders, the study found that in holometabolous species (those undergoing complete metamorphosis), minor males exhibit significantly steeper weapon allometric slopes than major males, whereas no such difference occurs in hemimetabolous species (those with incomplete or no metamorphosis). This pattern supports the hypothesis that resource limitations during pupal development in holometabolous species constrain weapon exaggeration in large males. The analysis also revealed that neither the degree of weapon exaggeration nor the method used to distinguish male morphs significantly affected allometric slope differences, and highlighted the need for further research on behavioral correlates and additional factors influencing weapon scaling.