Data from: A multigenerational effect of parental age on offspring size but not fitness in common duckweed (Lemna minor)

Classic theories on the evolution of senescence make the simplifying
assumption that all offspring are of equal quality, so that demographic
senescence only manifests through declining rates of survival or
fecundity. However, there is now evidence that, in addition to declining
rates of survival and fecundity, many organisms are subject to age-related
declines in the quality of offspring produced (i.e. parental age effects).
Recent modelling approaches allow for the incorporation of parental age
effects into classic demographic analyses, assuming that such effects are
limited to a single generation. Does this ‘single-generation’ assumption
hold? To find out, we conducted a laboratory study with the aquatic plant
Lemna minor, a species for which parental age effects have been
demonstrated previously. We compared the size and fitness of 423
lab-cultured plants (asexually-derived ramets) representing various birth
orders, and ancestral ‘birth-order genealogies’. We found that offspring
size and fitness both declined with increasing ‘immediate’ birth order
(i.e. birth order with respect to the immediate parent), but only
offspring size was affected by ancestral birth order. Thus, the assumption
that parental age effects on offspring fitness are limited to a single
generation does in fact hold for L. minor. This result will guide
theorists aiming to refine and generalise modelling approaches that
incorporate parental age effects into evolutionary theory on senescence.