RT Journal Article SR Electronic T1 Life history evolution and phenotypic plasticity in parasitic eyebrights (Euphrasia, Orobanchaceae) JF bioRxiv FD Cold Spring Harbor Laboratory SP 362400 DO 10.1101/362400 A1 Alex D. Twyford A1 Natacha Frachon A1 Edgar L. Y. Wong A1 Chris Metherell A1 Max R. Brown YR 2018 UL http://biorxiv.org/content/early/2018/07/04/362400.abstract AB Parasite lifetime reproductive success is determined by both genetic variation and phenotypically plastic life history traits that respond to host quality and external environment. In this study we use the generalist parasitic plant genus Euphrasia to test aspects of life history theory. We evaluate species life history strategies when grown on a common host, document phenotypic plasticity when grown on many different hosts, and relate our observations to trait differences recorded in the wild. We find Euphrasia in a common garden and in the field exhibit a range of life history strategies that differ between species that transition rapidly to flower at the expense of early season growth, and those that invest in vegetative growth and delay flowering. However, aspects of life history show extensive phenotypic plasticity in response to host quality, and demonstrate the costs of attaching to a low-quality host. Our experiments suggest life history strategies in a generalist parasitic plant are the product of natural selection on traits related to growth and flowering, while host quality may be a primary determinant of lifetime reproductive success.