Data for: Speciation in kleptoparasites of oak gall wasps often correlates with shifts into new tree habitats, tree organs, or gall morphospace

Host shifts to new plants can drive speciation for plant-feeding insects, but how commonly do host shifts also drive diversification for the parasites of those same insects? Oak gall wasps induce galls on oak trees, and shifts to novel tree hosts and new tree organs have been implicated as drivers of oak gall wasp speciation. Gall wasps are themselves attacked by many insect parasites, which must find their hosts on the correct tree species and organ, but which also must navigate the morphologically variable galls with which they interact. Thus, we ask whether host shifts to new trees, organs, or gall morphologies correlate with gall parasite diversification. We delimit species and infer phylogenies for two genera of gall kleptoparasites, Synergus and Ceroptres, reared from a variety of North American oak galls. We find that most species were reared from galls induced by just one gall wasp species, and no parasite species was reared from galls of more than four species. Most kleptoparasite divergence events correlate with shifts to non-ancestral galls. These shifts often involved changes in tree habitat, gall location, and gall morphology. Host shifts are thus implicated in driving diversification for both oak gall wasps and their kleptoparasitic associates.

寄主植物转换可推动植食性昆虫（plant-feeding insects）的物种形成（speciation），但这类寄主转换能否同样推动这些植食性昆虫的寄生虫的物种多样化（diversification），其普遍程度如何？栎瘿蜂（oak gall wasp）会在栎树表面诱导形成虫瘿（gall），而转换至新的栎树寄主及新的树体器官，被认为是推动栎瘿蜂物种形成的关键驱动因素。栎瘿蜂本身会受到多种昆虫寄生虫的侵染，这些寄生虫不仅需要在准确的树体物种与器官上定位寄主，同时还需适应与其互作的、形态各异的虫瘿。据此，本研究旨在探究寄主转换至新的栎树、器官或虫瘿形态类型，是否与虫瘿寄生虫的物种多样化存在关联。本研究针对从多种北美栎树虫瘿中采集饲养得到的两个盗寄生瘿蜂属——Synergus属与Ceroptres属——开展物种界定与系统发育（phylogeny）推演。研究结果显示，多数寄生虫物种仅从单一瘿蜂物种诱导形成的虫瘿中饲养得到，且未有任何寄生虫物种可从超过4个瘿蜂物种的虫瘿中被获取。多数盗寄生生物（kleptoparasite）的分化事件均与转换至非祖先寄主虫瘿相关，这类转换通常涉及树栖生境、虫瘿着生位置以及虫瘿形态的改变。综上，寄主转换被证实可同时推动栎瘿蜂及其盗寄生共生伙伴的物种多样化。