Abstract
Sperm competition, characterized by the formation of packages and its absence due to the formation of sperm plugs, occurs in some species of Brachyura, specifically in Heterotremata crabs. Spider crabs form sperm packages, while swimming crabs form sperm plugs. Plug-forming Portunids are paraphyletic to the group containing Aethridae, Calappidae, Cancridae, Leucosiidae, Menippidae, and Pa…