I am using the BaSTA package in R to estimate sex differences in survival parameters for a capture-recapture dataset. When I use a simple Gompertz model the parameters are very interpretable (b0 represents the baseline hazard and b1 represents age-dependent mortality rate, or senescence). However, when I look at a simple Weibull model, I'm not sure how to biologically interpret the differences in survival parameters. For my dataset, females have a higher shape parameter (b0) than males, but a lower rate parameter (b1) (see model output and plots). These differences are substantial enough to interpet according to the KLDC (0.88 and 0.99, respectively), but how would you interpret these differences biologically?
The best I can tell is that the shape parameter suggests that females show a later increase in age-specific mortality than males do. The higher rate parameter for males seems like it should mean males are senescing faster than females, but that isn't consistent with the visualization of the results. If males were senescing earlier and faster than females, I would expect them to have higher mortality rates than females at the oldest age classes, but instead it appears that the mortality hazard estimate is converging. Am I misinterpreting the parameters?