Are some conventional measures of the rate of ageing consistent with antagonistic pleiotropy?

Several measures of the rate of ageing have been proposed in the literature. But are they all equally good? In this work, three of these measures are considered: ωG and the parameter b for the Gompertz model, and ωW for the Weibull model. It is shown that ωG and ωW may fail to detect genuine changes in the rate of ageing when this rate varies in response to the fixation of antagonistic–pleiotropic mutations with effects on survival, while the parameter b never fails to detect such changes. It is suggested that ωG and ωW are inconsistent with the antagonistic pleiotropy model for the evolution of ageing. Hence, they should not be used to test any prediction that this model is supposed to entail about the evolution of the rate of ageing, notably, Williams' prediction according to which the higher the level of environmental mortality, the higher the evolutionarily favoured rate of ageing.

► ωG may not measure the rate of ageing under pleiotropy for survival.
► ωW may not measure the rate of ageing under pleiotropy for survival.
► ωW and ωG should not be used to test Williams' prediction about the rate of ageing.