Taxonomic Revision of the Malagasy Social Wasp Genus Ropalidia Guérin-Méneville (Hymenoptera: Vespidae)

A taxonomic revision of the social wasp genus Ropalidia from Madagascar is provided, based on 1543 examined specimens and 727 documented observations. In addition to 41 valid endemic species, 25 new species are described (R. andalana sp. nov., R. antoana sp. nov., R. aras sp. nov., R. beosi sp. nov., R. bevatana sp. nov., R. blommersi sp. nov., R. bongomaso sp. nov., R. janettae sp. nov., R. laureliniana sp. nov., R. mainty sp. nov., R. marolavaka sp. nov., R. miafina sp. nov., R. rafitra sp. nov., R. rampa sp. nov., R. seyrigi sp. nov., R. shattenbergi sp. nov., R. sonyae sp. nov., R. takona sp. nov., R. tapelaka sp. nov., R. tatsimo sp. nov., R. telperia sp. nov., R. tsiky sp. nov., R. vanga sp. nov., R. volontany sp. nov., R. zandry sp. nov.). Ropalidia obscurior Giordani Soika 1991 is a junior synonym of R. atra, syn. nov.; R. nilssoni Giordani Soika is a junior synonym of R. schulthessi (de Saussure), syn. nov.; R. venustula (de Saussure) is a junior synonym of R. ranavali (de Saussure), syn. nov. R. democratica (de Saussure) is treated as a nom. dub. COI analysis shows that the Malagasy species form a single lineage nested within the African mainland capensis group, indicating a single colonization of Madagascar followed by substantial adaptive radiation and a stunning demonstration of extant biodiversity. Green cuticular colour has evolved repeatedly within this radiation, and together with the concealed nests suggests that visual predation played a major role in the evolution of these species.