Sexual size dimorphism is a phenomenon where one sex is considerably larger than the other sex of the same species. Darwin himself wondered about how this can be, and today we still incompletely understand this pehnomenon.
Among all land animals, some spider species exhibit the most extreme cases of sexual size dimorphism. Recently, Kuntner and Coddington review the topic in Annual Review of Entomology, and Knowable magazine just published a nice popular science coverage of this research.
You can read it HERE!