Conserved and diverged patterns of senescence in Pristionchus nematodes

Healthspan, the period of life where organisms are without frailty and/or disease, is a major focus of biogerontological research. To understand late-life decline and increased mortality risk, short-lived organisms such as nematode worms are commonly used. Pristionchus nematodes are established models for evolutionary developmental genetics research and show promise as systems for comparative and experimental study of ageing. To support this, we developed phenotypic ageing profiles for the evo-devo model Pristionchus pacificus and its little-studied congener Pristionchus fissidentatus. We find that various life history traits differ between P. pacificus and P. fissidentatus (lifespan, brood size, and reproductive period), demonstrating their utility for studying divergent ageing trajectories. Further, several traits are consistently impacted by age, including intestinal barrier function, body size, and locomotory ability. Additionally, in P. pacificus, rupture avoidance, cuticle integrity, and feeding rate decline with age, indicating dysregulation across many tissue types. Several age-linked patterns resemble those documented for Caenorhabditis elegans despite considerable evolutionary distance, suggesting conserved senescent processes across the Rhabditida family of nematodes. This work highlights similarities and differences in the impact of ageing in two Pristionchus nematodes and supports their development as models for evolutionary genetic study of senescence.