Abstract
The cost of germline maintenance and repair gives rise to a trade-off between lowering the deleterious mutation rate and investing into life-history functions. Life-history and the mutation rate therefore coevolve, but this joint evolutionary process is not well understood. Here, we develop a mathematical model to analyse the long-term evolution of traits affecting life-history and the deleterious mutation rate. First, we show that under certain biologically feasible conditions, the evolutionary stable life-history and mutation rate can be characterised using the basic reproductive number of the least-loaded class. This is the expected lifetime production of offspring without deleterious mutations born to individuals with no deleterious mutations. Second, we analyse two specific biological scenarios: (i) coevolution between reproductive effort and mutation rate and (ii) coevolution between age-at-maturity and mutation rate. These two scenarios suggest two broad results. First, the trade-off between lowering mutation rate vs investing into life-history functions depends strongly on environmental conditions and baseline mutation rate. Second, the trade-offs between different life-history functions can be strongly affected by mutation rate coevolution and higher baseline mutation rates select for faster life histories: (i) higher investment into fecundity at the expense of survival and (ii) earlier age of maturation at smaller sizes.
Competing Interest Statement
The authors have declared no competing interest.
