We question the rationale for a vulnerability cost for this display and suggest instead that soft song has a competing functions cost, in that, by using soft song to counter an intruder, a male sacrifices other possible functions of vocal signaling.
Despite the intuitive appeal of a trade-off between two competing functions, negative covariance in such traits are not frequently observed when phenotypic comparisons are made between individuals within a population48,49.
Far from being inert, therefore, the risk management strategy represented by adipose tissue plays a proactive role in allocating energy between competing functions (Wells, 2009c), thereby contributing to life-history strategy and promoting reproductive fitness (Hill, 1993).
Our findings illustrate how PRCs sought to reconcile the competing functions of the prenatal record as a comprehensive clinical guide for a range of health indicators, a legal documentation tool, and a data source for perinatal health surveillance.
Evolution of life-history traits is predicted to be a consequence of how resources are allocated to competing functions such as reproduction, growth and maintenance.
PRC decision-making was complex, revealing the competing functions of the prenatal record as a clinical guide, documentation tool and data source.
Representative stakeholder involvement along with processes to support constructive debates of the evidence would ensure more valid interpretation of the research evidence within the wider clinical and social context, as well as help PRCs negotiate the competing functions of the prenatal records in a way that maximizes benefits to patient and population health outcomes.
One of the key tenets of life-history theory is that a finite amount of energy must be divided (i.e. traded off) between competing functions, of which the most important are maintenance, growth, reproduction and immune function, and between current versus future reproduction (Hill, 1993).
Water serves two competing functions.
Among these pressures were their competing functions as both dramatic narratives and assemblies of clinical data or, to use metaphors common during that period, the world of the theatre and of the granary.
Carotenoids acquired in the diet should be optimally distributed among competing functions, that is, allocated to either signal expression or to reduce oxidative stress [7].
