Evolution of the parasitic wasp subfamily Rogadinae (Braconidae): phylogeny and evolution of lepidopteran host ranges and mummy characteristics

[Background] The braconid subfamily Rogadinae is a large, cosmopolitan group of endoparasitoid wasps characterised by 'mummifying' their lepidopteran host larvae, from which the adult subsequently emerges. Rogadines attack a variety of both macro- and microlepidopteran taxa, although the speciose genus Aleiodes almost exclusively attacks macrolepidopterans. Here, we investigate the phylogenetic history of the Rogadinae, revise their higher-level classification and assess the evolution of their host ranges and mummy types. We also assess the divergence times within the subfamily and discuss the reasons for the extraordinary evolutionary diversification of Aleiodes.[Results] Our Bayesian analyses weakly support the monophyly of the subfamily. A clade comprising all Aleiodes species and some other taxa is not nested within the tribe Rogadini as previously supposed, but instead is recovered as sister to the Yeliconini, with the remaining Rogadini genera being recovered as sister to the Stiropiini. The Rogadinae is estimated to have originated during the mid to late Eocene, 36.1–51.62 MYA. Molecular dating gives a more recent origin for the Aleiodes clade (17.98–41.76 MYA) compared to the origins proposed for two of its principal lepidopteran host groups (Noctuidae: 60.7–113.4 MYA; Geometridae 48–62 MYA). The Bayesian ancestral reconstruction of the emergence habits from the mummified hosts weakly recovered an anterior emergence as the ancestral condition for the subfamily. Producing a hard mummy has evolved at various times independently, though most of the species with this biology belong to the Aleiodes clade.[Conclusion] Based on our results, we erect the tribe Aleiodini nov. to include Aleiodes and Heterogamus stat. rev. Cordylorhogas, Pholichora and Hemigyroneuron are synonymised with Aleiodes. The molecular dating of clades and the ancestral reconstruction of host ranges support the hypothesis that radiation within Aleiodes s. s. was due to host recruitment leading to host range expansion followed by speciation, and not to parasitoid-host coevolution. Within the Rogadinae, variation in the site of emergence from the mummified host probably evolved as a consequence of the mummy's site and mode of formation, and the extent of mummy tanning/hardness to the degree of protection needed in relation to the cost of providing it.AZR and AGS were supported by programs "Juan de la Cierva" and "Ramón y Cajal", respectively, and their research was funded by Plan Nacional I+D (CGL2005-00307 to AGS), all from the Spanish Ministry for Education and Science. We also thank a Natural Environment Research Council grant to DLJQ (NE/C519538), grants given by the Russian Foundation for Basic Research (N 07-04-00454) and the Presidium RAS Program "Origin and evolution of Biosphere, Subprogram II", to SAB, and two grants given by the National Science Foundation (projects BSI-03-46729 and BSI-07-17458; Caterpillars and Parasitoids of the Eastern Andes) to SRS.Peer reviewe

Evolution of the parasitic wasp subfamily Rogadinae (Braconidae): phylogeny and evolution of lepidopteran host ranges and mummy characteristics

Abstract Background The braconid subfamily Rogadinae is a large, cosmopolitan group of endoparasitoid wasps characterised by 'mummifying' their lepidopteran host larvae, from which the adult subsequently emerges. Rogadines attack a variety of both macro- and microlepidopteran taxa, although the speciose genus Aleiodes almost exclusively attacks macrolepidopterans. Here, we investigate the phylogenetic history of the Rogadinae, revise their higher-level classification and assess the evolution of their host ranges and mummy types. We also assess the divergence times within the subfamily and discuss the reasons for the extraordinary evolutionary diversification of Aleiodes. Results Our Bayesian analyses weakly support the monophyly of the subfamily. A clade comprising all Aleiodes species and some other taxa is not nested within the tribe Rogadini as previously supposed, but instead is recovered as sister to the Yeliconini, with the remaining Rogadini genera being recovered as sister to the Stiropiini. The Rogadinae is estimated to have originated during the mid to late Eocene, 36.1–51.62 MYA. Molecular dating gives a more recent origin for the Aleiodes clade (17.98–41.76 MYA) compared to the origins proposed for two of its principal lepidopteran host groups (Noctuidae: 60.7–113.4 MYA; Geometridae 48–62 MYA). The Bayesian ancestral reconstruction of the emergence habits from the mummified hosts weakly recovered an anterior emergence as the ancestral condition for the subfamily. Producing a hard mummy has evolved at various times independently, though most of the species with this biology belong to the Aleiodes clade. Conclusion Based on our results, we erect the tribe Aleiodini nov. to include Aleiodes and Heterogamus stat. rev. Cordylorhogas, Pholichora and Hemigyroneuron are synonymised with Aleiodes. The molecular dating of clades and the ancestral reconstruction of host ranges support the hypothesis that radiation within Aleiodes s. s. was due to host recruitment leading to host range expansion followed by speciation, and not to parasitoid-host coevolution. Within the Rogadinae, variation in the site of emergence from the mummified host probably evolved as a consequence of the mummy's site and mode of formation, and the extent of mummy tanning/hardness to the degree of protection needed in relation to the cost of providing it.</p