Host specialization is ancestral in Torymus (Hymenoptera, Chalcidoidea) cynipid gall parasitoids



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Gil Tapetado, Diego and Durán Montes, Patricia and García París, Mario and López Estrada, E. Karen and Sánchez Vialas, Alberto and Jiménez Ruiz, Yolanda and Gómez, José F. and Nieves Aldrey, José Luis (2021) Host specialization is ancestral in Torymus (Hymenoptera, Chalcidoidea) cynipid gall parasitoids. Zoologica Scripta, 51 (1). pp. 91-118. ISSN 1463-6409

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The host range of parasitoids varies greatly among species: Some only parasitize one to a few hosts (specialists), while others parasitize multiple species or a variety of host types (generalists). The direction of most host range shifts in parasitoid groups, that is from generalist to specialist or, alternatively, from specialist to generalist, is unknown. To explore the origin of host range shifts, we studied a clade within the genus Torymus (Hymenoptera, Chalcidoidea) that includes both generalist and specialist parasitoids of Cynipidae (Hymenoptera). We analysed the phylogenetic relationships of the species of Torymus on the basis of two gene fragments (cox1 and ITS2) of 246 specimens and performed an ancestral state reconstruction of the specialist/generalist trait. Our results revealed the following: (a) The ancestral state of this group of Torymus is specialist, with the generalist state evolving through a loss of specialization. (b) The species Torymus cyaneus and Torymus flavipes both have a strong genetic structure, suggesting the existence of different biological identities. (c) There has been a host plant shift in the lineage(s) leading to Torymus rubi and Torymus bedeguaris from galls on Quercus to those on Rosaceae. (d) The alien species Torymus sinensis and the native European species Torymus notatus are phylogenetically closely related. (e) Speciation within Torymus was likely associated with the diversification of their cynipid hosts, which itself was driven by the dramatic changes in climate and vegetation that occurred during the Miocene.

Item Type:Article
Uncontrolled Keywords:cryptic species; Cynipidae; host plant shift; host range; Torymidae; Torymus sinensis
Subjects:Medical sciences > Biology > Ecology
Medical sciences > Biology > Insects
ID Code:74060
Deposited On:04 Aug 2022 14:28
Last Modified:05 Aug 2022 07:30

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