Reserve dynamics & social interactions in feeding Bas Kooijman Dept theoretical biology Vrije Universiteit Amsterdam Amsterdam 2005/08/15

Evolution of DEB systems

Reserve dynamics

Polymerization inhibition maintenance growth catabolism

Structural homeostasis usual ontogeny V E Enzymes at interface that mobilize reserves don’t “observe” grain size or substrate conc. No dilution by growth structure reserve

Volume-surface interactions inactive enzyme active enzyme in binding phase active enzyme in production phase product substrate Cells can “know” their size from the rate at which concentrations of substrate & product change if transformation is by membrane-bound enzymes Membrane-mediated transformation rates in isomorphs decrease with length because of transportation distance

Protein synthesis 7.5 spec growth rate, h -1 scaled spec growth rate RNA/dry weight, μg.μg -1 scaled elongation rate Data from Koch 1970 Data from Bremer & Dennis 1987 RNA = w RV M V + w RE M E dry weight = w dV M V + w dE M E

These gouramis are from the same nest, they have the same age and lived in the same tank Social interaction during feeding caused the huge size difference Age-based models for growth are bound to fail; growth depends on food intake : These gouramis are from the same nest, they have the same age and lived in the same tank Social interaction during feeding caused the huge size difference Age-based models for growth are bound to fail; growth depends on food intake No age, but size: Trichopsis vittatus

Rules for feeding

Social interaction  Feeding time reserve density length time 1 ind 2 ind determin expectation