reported by Bas Kooijman.
Konstadia Lika (Dept of Biology, University of Crete) visited the
Dept. of Theoretical Biology of the Vrije Universiteit (22-27 March
1999) within the framework of the NWO priority program NLS. She worked
for 6 years with Tom Hallam (Knoxville, Tennessee), and 2 years with
Roger Nisbet (Santa Barbara, California), on Dynamic Energy Budgets of
the production type. In this class of models, maintenance requirements
are first subtracted from assimilation, before allocation to growth
and/or reproduction. Kooijman is working on assimilation models, where
assimilation feeds a buffer that is subsequently used for maintenance,
development, growth and reproduction. She will talk about this work in
the coming TMBM99 conference in Amsterdam. She worked with Kooijman on
the comparison of reproduction in animals that sport determinate or
indeterminate growth. The topic originated from Roger Nisbet, who
suggested that animals that allocate a constant fraction of energy made
available from reserves to maintenance plus growth (standard assumption
in DEB model), would soon be out-competed by animals that first grow
and then reproduce. The analyses by Like and Kooijman show that this is
not true; the reverse is to be expected in practice. They are working
on a paper with the following provisional title:
Life history implications of allocation to growth versus
reproduction in Dynamic Energy Budgets
Abstract: We compare the implications of determinate versus indeterminate growth of a parthenogenetic iteroparous ectotherm at constant food density in the context of the Dynamic Energy Budget theory, which specifies the tight links between life history traits, such as feeding, aging, growth and reproduction. The allocation of a constant fraction of the catabolic power to somatic maintenance and growth leads to a higher life span reproduction and a longer life span, while a bang-bang allocation leads to a higher reproduction just after maturation, and a higher population growth rate. We suggest an evolutionary link between allocation strategies and expected life span.