THE PHYSIOLOGICAL ECOLOGY OF DAPHNIA - DEVELOPMENT OF A MODEL OF GROWTH AND REPRODUCTION

Proposes and tests a new hypothesis based on the idea that allometric relationships for physiological rates are stage dependent. Ingestion rates increase much faster with juvenile body size than with adult body size for several Daphnia species. Allometric relationships for respiration are not stage dependent. A maintenance function takes into account overheads associated with growth and basal metabolic rates. The new allometric relationships for ingestion and maintenance, along with an accurate description of the onset of maturity and partitioning of energy between growth and reproduction, can account for the sigmoid growth pattern displayed by Daphnia. Existing models cannot explain Daphnia's performance when food availability is low: the authors therefore examined how Daphnia stores energy and uses reserves. (See also 90L/11277). -from Authors