A new paper by Lika and coworkers in the Journal of Theoretical Biology quantifies where species lie on the supply-demand spectrum.
Konstadia Lika, Starrlight Augustine, Laure Pecquerie, Sebastiaan A.L.M. Kooijman
The bijection from data to parameter space with the standard DEB model quantifies the supply-demand spectrum
Journal of Theoretical Biology 2014 http://dx.doi.org/10.1016/j.jtbi.2014.03.025
The standard Dynamic Energy Budget (DEB) model assumes that food is converted to reserve and a fraction κ of mobilised reserve of an individual is allocated to somatic maintenance plus growth (allocation fraction to soma). The rest is allocated to maturity maintenance plus maturation (in embryos and juveniles) or to reproduction (in adults).
The add my pet collection of over 300 animal species from most larger phyla, and all chordate classes, shows that this model fits energy data very well. Nine parameters determine nine data points at abundant food:
- Dry/wet weight ratio
- age at birth
- age at puberty
- age at death
- weight at birth
- weight at metamorphosis
- weight at puberty
- ultimate weight
- ultimate reproduction rate
We demonstrate that, given a few other parameters, these nine data points also determine the nine parameters uniquely that are independent of food availability:
- maturity at birth
- maturity at metamorphosis
- maturity at puberty
- specific assimilation
- somatic maintenance
- costs for structure,
- allocation fraction to soma
- energy conductance,
- ageing acceleration
We provide an efficient algorithm for mapping between data and parameter space in both directions and found expressions for the boundaries of the parameter and data spaces. It turned out that one of the boundaries quantifies the position of species in the supply-demand spectrum, which reflects the internalisation of energetic control.
In this study, we link eco-physiological properties of species to their position in this spectrum and discuss it in the context of homeostasis. Invertebrates and ray-finned fish turn out to be close to the supply end of the spectrum, while other vertebrates, including cartilaginous fish, have stronger demand tendencies. We explain why birds and mammals up-regulate metabolism during reproduction.
Read the full article at the Journal of Theoretical Biology