ИСТИНА

Reproductive mode, ancestry, and climate are recognized determinants of body-size variation in reptiles but their effects have rarely been estimated simultaneously, especially at the intraspecific level. The Common lizard (Zootoca vivipara) occupies almost the entire Northern Eurasia and includes viviparous and oviparous lineages, thus representing an excellent model for such studies. Using body length data for >10,000 individuals from 72 geographically distinct populations over the species range we analysed how sex-specific adult body-size and sexual size dimorphism (SSD) is associated with reproductive mode, lineage identity, and several climatic variables. Variation in male size was weak and irregular. In contrast, female size and SSD varied considerably, demonstrating significant effects of reproductive mode and particularly seasonality. Populations of the Western Oviparous lineage (northern Spain, south-western France) exhibited a smaller female size and less female-biased SSD than those of the Western Viviparous (France to Eastern Europe) and the Eastern Viviparous (Eastern Europe to Far East) lineages; this pattern persisted even after controlling for climatic effects. The phenotypic response to seasonality was complex: across the lineages, as well as within the Eastern Viviparous lineage, female size and SSD increase with increasing seasonality, whereas the Western Viviparous lineage followed the opposing trends. Altogether, viviparous populations seem to follow a saw-tooth geographic cline, which might reflect the non-monotonic relationship of population's typical body size at maturity in females with the length of activity season predicted by Adolph & Porter's model. The SSD allometry followed the converse of Rensch's rule, a rare pattern for amniotes.