Trade-off between local persistence and rapid expansion: a case study of a parthenogenetic lizard species and its sexually reproducing ancestor

Parthenogenetic lineages are often portrayed as rapid colonizers with short lifespans, but how reproductive mode shapes life-history trajectories in close relatives remains unclear. Using Caucasian rock lizards ( Darevskia ) as a model, we compared age structure, growth dynamics, and reproductive traits in the hybrid parthenogenetic lizard ( D. armeniaca ) and its sexually breeding progenitors ( D. valentini , D. mixta ). Age was inferred by skeletochronology of phalangeal cross-sections; growth was estimated from distances between successive lines of arrested growth (LAGs). Reproductive traits were integrated from published datasets and re-analyzed. Parthenogenetic lineages tended to show age distributions consistent with earlier maturation, higher reproductive allocation, and shorter lifespan than their sexual relatives. D. armeniaca showed higher reproductive effort relative to body mass, earlier age of maturation, and lower proportion of individuals with long lifespan than its patrilineal progenitor, D. valentini from the same location. Population modeling suggests that the parthenogens would expand faster throughout neighboring habitats than the sexual breeders, which is in line with the observation that they occupy a greater fraction of suitable habitat within their ranges. These differences suggest a demographic mechanism by which unisexual lineages may expand faster, whereas sexual lineages may persist longer under variable conditions, potentially contributing to their long-term coexistence.