title: The elusive life cycle of scyphozoan jellyfish--metagenesis revisited.
abstract: Massive proliferations of scyphozoan jellyfish considerably affect human industries and irreversibly change food webs. Efforts to understand the role of jellyfish in marine ecosystems are based on a life cycle model described 200 years ago. According to this paradigm the pelagic medusae is considered seasonal and alternates with the benthic polyp stage from which it derives. However, we provide evidence that a) the occurrence of several species of medusae is not restricted to a season in the year, they overwinter, b) polyp- and medusa generations are neither temporally nor spatially separated, and c) "metagenesis" which is defined as the alternation between sexual and asexual generations does not always occur. Hence we recommend additions to the current model and argue that the scyphozoan life cycle should be considered multi-modal, rather than metagenetic. The implications of these findings for jellyfish proliferations, including possible consequences and associated environmental drivers, are discussed.
authors.affiliation: 1] Universidad de Antofagasta, Instituto de Ciencias Naturales Alexander von Humboldt, Climate Change Ecology Group, CENSOR Laboratory, Av. Universidad de Antofagasta 02800, Antofagasta, Chile [2] Murdoch University Perth, School of Veterinary and Life Sciences, Murdoch, WA 6150, Australia.
authors.forename: Janja
authors.initials: J
authors.lastname: Ceh
authors.affiliation: Universidad de Antofagasta, Instituto de Ciencias Naturales Alexander von Humboldt, Climate Change Ecology Group, CENSOR Laboratory, Av. Universidad de Antofagasta 02800, Antofagasta, Chile.
authors.forename: Jorge
authors.initials: J
authors.lastname: Gonzalez
authors.affiliation: Universidad de Antofagasta, Instituto de Ciencias Naturales Alexander von Humboldt, Climate Change Ecology Group, CENSOR Laboratory, Av. Universidad de Antofagasta 02800, Antofagasta, Chile.
authors.forename: Aldo S
authors.initials: AS
authors.lastname: Pacheco
authors.affiliation: Universidad de Antofagasta, Instituto de Ciencias Naturales Alexander von Humboldt, Climate Change Ecology Group, CENSOR Laboratory, Av. Universidad de Antofagasta 02800, Antofagasta, Chile.
authors.forename: José M
authors.initials: JM
authors.lastname: Riascos
mesh_terms: D000818:Animals; D017753:Ecosystem; D020387:Food Chain; D008018:Life Cycle Stages; D016015:Logistic Models; D008954:Models, Biological; D037401:Scyphozoa / Q000235:genetics / Q000254:growth & development*; D012621:Seasons