Figure 3.

Known locations of galls on oaks for our Nearctic gall wasp set. Many cynipid gall wasps undergo cyclical parthenogenesis and have both asexual (“Asex”) and sexual (“Sex”) generations that gall different oak organs. Empty spaces indicate missing data and are in many cases due to the gall wasp having been described only from one generation. It is also possible that in some cases only one generation exists (e.g., Andricus quercuscalifornicus), although this is apparently rare in the Cynipini (Pujade‐Villar et al. 2001; Stone et al. 2008). Although taxon sampling and incomplete data prevent a formal reconstruction of location and number of host switches, we have mapped one possible minimum‐change scenario onto branches of the phylogeny: dark circles indicate changes in host organ by the sexual generation, assuming an ancestral association with leaves. Open circles indicate changes in host organ by the asexual generation, again assuming an ancestral association with leaves. Myriad other scenarios exist but in all cases would show that changes in host organ use have been common for both gall wasp generations.