MEPS 318:81-88 (2006)  -  doi:10.3354/meps318081

Integrating developmental clocking and growth in a life-history model for the planktonic chordate Oikopleura dioica

Dag L. Aksnes1,*, Christofer Troedsson2, Eric M. Thompson2

1Department of Biology, University of Bergen, PO Box 7800, 5020 Bergen, Norway
2Sars International Centre for Marine Molecular Biology, Thormøhlensgaten 55, 5008 Bergen, Norway

ABSTRACT: We present a novel modelling approach applied to the appendicularian Oikopleura dioica. Growth and development are represented as separate processes, and a developmental clock is assumed to regulate development. Temperature influences the organism globally through aging and not separately through individual physiological processes as commonly applied in ecological models, and physiological rates are outputs rather than model inputs. The model accounts for development, growth, metabolic rates and life-history characteristics, with relatively few equations and parameters. Parameter values needed for simulations were derived from published data on the development of Caenorhabditis elegans and O. dioica. Comparisons of simulated generation times, respiration rates, assimilation rates and growth rates with independent data demonstrated predictive capability, but also raised inconsistencies that deserve future experimentation. The present model frames several testable predictions concerning development, growth and metabolic rates in multicellular organisms. Specifically, it suggests that the allometric scaling of metabolism to temperature and body mass should change when food limitation slows growth but not development.


KEY WORDS: Oikopleura · Life history · Growth · Development · Aging · Allometry


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