Abstract
Old parental age is commonly associated with negative effects on offspring life-history traits. Such parental senescence effects are predicted to have a cumulative detrimental effect over successive generations. However, old parents may benefit from producing higher quality offspring when these compete for seasonal resources. Thus, old parents may choose to increase investment in their offspring, thereby producing fewer but larger and more competitive progeny. We show that Caenorhabditis elegans hermaphrodites increase parental investment with advancing age, resulting in fitter offspring who reach their reproductive peak earlier. Remarkably, these effects increased over six successive generations of breeding from old parents and were subsequently reversed following a single generation of breeding from a young parent. Our findings support the hypothesis that offspring of old parents receive more resources and convert them into increasingly faster life histories. These results contradict the theory that old parents transfer a cumulative detrimental ‘ageing factor’ to their offspring.
Highlights
The influence of parental age on offspring phenotypic quality has been widely reported in many taxa [1,2,3] and is the subject of renewed theoretical [4,5,6,7] and empirical interest [8,9,10]
We found parental age effects on offspring total reproduction and individual fitness across one generation, we found some evidence for cumulative effects over successive generations
Like the increase in lifespan across all parental regimes, we found increased total reproduction in both the young and old parental propagation regimes over successive generations, which may be owing to a general increase in worm condition over time
Summary
The influence of parental age on offspring phenotypic quality has been widely reported in many taxa [1,2,3] and is the subject of renewed theoretical [4,5,6,7] and empirical interest [8,9,10]. To test whether accumulated parental effects on fitness were reversible after six generations, we continued the experiment for an additional generation (generation seven) In this final generation, we used a fully factorial design to measure reproduction in offspring from 1- and 3-day old adults from both the young and the old propagation regimes (figure 1). In analyses from the intergenerational experiment where assays were conducted in generations one, three and six, we included the main effects of parental propagation regime (young, old and switched) and generation, and their interaction. To investigate the reversibility of parental effects in generation seven, we calculated λind and fitted an LMM with parental propagation regime (young and old) and the proximate parental age (1- and 3-day old parents) included as a fixed effect, and ancestral lines as random intercepts. For development time and adult size, we fitted parental age as a fixed effect, and random intercepts for parent ID
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Proceedings of the Royal Society B: Biological Sciences
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
