Food limitation. spination, and reproduction in Brachionus calyciflorus

Abstract

The Brachionus culycifrartls polymorphism involves both a chemical secreted by the predatory rotifer Asplanchna and food concentration. Food concentration accounted for 30-37% of the explained variance in spine length in treatments containing Asplanchna factor. The longest spines developed only in low-food conditions containing the Asplanchna chemical, indicating that the factors were additive. Newborns exposed only to low concentrations of food during the first 3 d after hatching developed relatively long spines and smaller body sizes than their high-food-adapted mothers.The population growth rate of the Asplanchna-induced phenotype was significantly higher than that of the short-spined controls over a wide range of food concentrations (0.4-l 5.0 pg ml-l dry mass of algae). Most importantly, elongated spines were associated with a reduced threshold food concentration for reproduction, suggesting that they return an energetic benefit exceeding their developmental and maintenance costs.

Invited Review - Fight on Plankton! or, Phytoplankton Shape and Size as Adaptive Tools to Get Ahead in the Struggle for Life

“…Theory predicts trade-offs to be important in systems with inducible defenses and therefore we also include alternative trade-off scenarios in the sensitivity analysis. Dumont et al (1975);3, JOErgensen et al (1991);4, Gilbert & Waage (1967);5, Gilbert (1976);6, Walz (1993);7, Nandini & Sarma (1999);8, Lürling & Van Donk (2000);9, Laroque et al (1996); 10, Stemberger (1990);11, A.M. Verschoor (chapter 4);12, Iyer & Rao (1996);13, Gilbert (1967). Note: The Methods section explains the sensitivity analysis.…”

Rotifers from diapausing, fertilized eggs: Unique features and emergence

“…The morphological reduction, like that in the aptera form of Polyarthra, may be either a developmental constraint or a cost-saving adaptation permitting greater reproduction. However, two studies were unable to detect any cost associated with the development and presence of long posterolateral spines (Gilbert 1980c(Gilbert , 1999Stemberger 1990). …”

“…In the absence of the Asplanchna kairomone, these spines may be completely lacking in some clones or long in other clones. Longer spines can be produced at low temperatures and food concentrations (Halbach 1970;Stemberger 1990). The length of the anterior and posteromedian spines increases with that of the posterolateral spines.…”

Maternal age and spine development in a rotifer: ecological implications and evolution

“…The much more modest spine-development responses of B. calyciflorus to low temperature and low food availability are less clearly beneficial, but may increase fitness by reducing the rotifer's sinking rate (Stemberger 1990, Gilbert 2011b.…”

“…Short posterolateral spines can be induced by low temperature and low food concentration (Gilbert 1967, Halbach 1970a, Stemberger 1990, and very long ones can be induced by a kairomone from the predatory rotifer Asplanchna ( Fig. 1; Gilbert 1967, 1980, 2011a, Halbach 1970a, Stemberger 1990.…”