The independent evolution of the metafemoral spring in Coleoptera

Abstract. The metafemoral spring (jumping organ) was known previously only from all Alticinae (Chrysomelidae), one genus of Bruchidae, and two species of Rhynchaeninae (Curculionidae). Here this spring is reported from three subfamilies, seven tribes and twenty-two genera of Curculionidae (three Rhychaeninae, one Erirhininae (Derelomini), and eighteen Ceutorhynchinae) and also from five genera of Buprestidae (four Agrilinae and one Trachyinae). Jumping in Hexapoda is discussed, specifically in the other jumping Coleopteran families that were examined for the presence of the spring (e.g. Melandryidae, Mordellidae, Scraptiidae, Eucinetidae, Limnichidae, Scirtidae and Anthribidae). The phylogenetic value of the metafemoral spring is still unclear; however, there are indications that it is useful in assessing relationships among weevil tribes. As in Alticinae, Curculionidae and Buprestidae have constant intra-generic spring morphology and inter-generic differences. The spring in Bruchidae, Curculionidae and Buprestidae has a simpler morphology than in the Alticinae, but still possesses the features necessary for jumping (metatibial extension). The metafemoral spring has apparently evolved independently in Alticinae, Bruchidae, Curculionidae and Buprestidae, and is an example of convergent evolution.