Abstract
Corals in the genus Pocillopora are the primary framework builders of eastern tropical Pacific (ETP) reefs. These corals typically associate with algal symbionts (genus Symbiodinium) in clade C and/or D, with clade D associations having greater thermal tolerance and resistance to bleaching. Recently, cryptic "species" delineations within both Pocillopora and Symbiodinium have been suggested, with host–symbiont specificity used as a supporting taxonomic character in both genera. In particular, it has been suggested that three lineages of Pocillopora (types 1–3) exist in the ETP, of which type 1 is the exclusive host of heat-tolerant Symbiodinium D1. This host specificity has been used to support the species name "Symbiodinium glynni" for this symbiont. To validate these host–symbiont relationships and their taxonomic utility, we identified Pocillopora types and their associated Symbiodinium at three sites in the ETP. We found greater flexibility in host–symbiont combinations than previously reported, with both Pocillopora types 1 and 3 able to host and be dominated by Symbiodinium in clade C or D. The prevalence of certain combinations did vary among sites, showing that a gradient of specificity exists which may be mediated by evolutionary relationships and environmental disturbance history. However, these results limit the utility of apparent host–symbiont specificity (which may have been a result of undersampling) in defining species boundaries in either corals or Symbiodinium. They also suggest that a greater diversity of corals may benefit from the thermal tolerance of clade D symbionts, affirming the need to conserve Pocillopora across its entire geographic and environmental range.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.