Trade-off between local survival and fast expansion: a case study of two parthenogenetic lizard species and their patrilineal ancestors

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 hybrid parthenogenetic lizards ( D. armeniaca , D. dahli ) and their sexually breeding progenitors ( D. valentini , D. portschinskii , D. mixta ). Age was inferred by skeletochronology of phalangeal cross-sections; growth by between-LAG increments. reproductive traits were integrated from published datasets. Parthenogens tend to have faster life histories: earlier maturation, higher reproductive allocation, higher adult mortality, and shorter lifespans than their sexual relatives. D. armeniaca showed higher reproductive effort relative to body mass, earlier age of maturation, shorter lifespan, and slower deceleration of growth after the 3rd year of life than its patrilineal progenitor, D. valentini from the same location. At the species level, irrespective to a location, D. dahli has earlier age of maturation, and shorter lifespan than its patrilineal progenitor, D. portschinskii . Population modeling suggests that the parthenogens would faster expand 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 complementary colonizer–competitor strategies provide a parsimonious demographic mechanism for the long-term coexistence of unisexual and sexual Darevskia lineages.