DOI: 10.5061/dryad.tk5ph
title: Data from: Patterns of age-related change in reproductive effort differ in the pre-natal and post-natal periods in a long-lived mammal

description: Age-related changes in maternal reproductive allocation for long-lived
 species are a key prediction from life-history theory. Theoretical and
 empirical work suggests that allocation may increase with age due to
 constraint (increases with experience) or restraint (increases with age in
 the face of declining residual reproductive value), and may decrease among
 the oldest aged animals due to senescence in reproductive function. Here,
 we use a hierarchical modelling approach to investigate the age-related
 patterns of change in maternal reproductive effort in the Weddell seal, a
 long-lived marine mammal with a protracted period of maternal care during
 which mothers allocate a large proportion of body mass while feeding
 little. We find that maternal allocation increases with age for young
 mothers during both the pre-natal and post-natal periods. In contrast,
 older mothers demonstrate a senescent decline in pre-natal allocation but
 allocate more of their declining resources to their offspring during the
 post-natal period. We also find strong evidence for the importance of
 individual effects in reproductive allocation among mothers: some mothers
 consistently produce heavier (or lighter) pups than expected. Our results
 indicate that maternal allocation changes over a mother's
 reproductive life span and that age-specific differences differ in notable
 ways in pre-natal and post-natal periods.
description: Data for maternal masses
 near parturition.This file contains the
 data used for models of maternal mass near parturition and contains the
 following columns: Mass (kg), momAGE.c (maternal ages in years at
 weighing, centered using the mean), momAGE.c.sq (the square of the
 previous term), momAGE.log (the log transform of maternal age in years,
 made by subtracting the minimum age from each animal and adding a small
 constant), PrevState (breeding state the previous season), NPrevPup.c (the
 number of previous pups for each mother, scaled by the average number of
 pups at each age), Season (year of measurement).mommasses_publication.csvData for pup masses near parturition, and daily gains during early and late lactationThis file contains the data used for models of pup mass near parturition and contains the following columns: PartMass (kg), momAGE.c (maternal ages in years at weighing, centered using the mean), MidGain (kg/day for the first 20 days), LateGain (kg/day for days 20 to 35), Season (year of measurement), DTA (deviation from target age), Female (indicator variable for female), Btime.c (birthdate centered using the mean), Btime.c.sq (square of the previous term), momSPENO (unique identifier for mother), momAGE.c.sq (the square of the previous term), momAGE.log (the log transform of maternal age in years, made by subtracting the minimum age from each animal and adding a small constant), NPrevPup.c (the number of previous pups for each mother, scaled by the average number of pups at each age), PrevState (breeding state the previous season), PartMass.c (parturition mass centered according to the mean).pupmasses_publication.csv