Fine-scale habitat heterogeneity affects embryonic development but not female reproduction in a lizard from desert...

Reduced vegetation cover, elevated surface temperature, and decreased soil moisture are the main characteristics of desertification. Environmental variables in ectotherms' natural nests may drive their adaptive life-history evolution. To investigate the effect of variations in nest temperature, moisture, and vegetation cover on the reproductive phenotype and embryonic development of Phrynocephalus przewalskii, we selected two populations that inhabit environments with different vegetation cover. We also conducted a reciprocal egg swap experiment to analyze the effects of nest environment and population origin on embryonic and offspring development. Although fine-scale environmental heterogeneity was detected between low- and high-vegetation-cover populations, no significant differences in female reproductive characteristics, including clutch size, average egg mass, clutch mass, and relative clutch mass, were observed between populations. However, we found that egg incubation period and hatching success were influenced by the nesting environment. Specifically, individuals that grew in low-vegetation-cover sites had shorter incubation periods and higher hatching success rates than those in high-vegetation-cover sites. The hatchling growth rate was significantly higher in the high-vegetation-cover population, yet the overwintering survival rate was higher in the low-vegetation-cover population. These results indicated that fine-scale habitat heterogeneity does not significantly affect the reproductive output of female lizards, offspring growth, or survival rates. However, it does affect embryonic development, including the incubation period and hatching success. Our study highlights the effects of fine-scale habitat heterogeneity on female reproduction and embryonic and offspring development and suggests that desert toad-headed agamas may be resilient to variations in environmental conditions associated with desertification.