[Geographic variation in female reproductive characteristics and egg incubation of Eumeces chinensis]

Geographic variation in female reproductive characteristics and egg incubation of Chinese skink (Eumeces chinensis) was studied by using two populations from eastern (Lishui, Zhejiang) and southern (Shaoguan, Guangdong) China, respectively. The results showed that female adults of the two populations both laid a single clutch per breeding season, and the clutch size, clutch mass, and egg mass had a positive correlation with female SVL. There was obvious geographic variation in head shape of females, reproductive characteristics, timing date of oviposition, and thermal dependence of egg incubation between two populations. Skinks from Shaoguan began to lay eggs in mid-May, approximately two weeks earlier than the timing date of skinks from Lishui. Skinks from Shaoguan produced more but smaller eggs. The size-specific (SVL) clutch size of skinks from Shaoguan outnumbered that of skinks from Lishui by 2.8 eggs. It implied there was a trade-off between the number and the size of offspring between populations, because there was no difference in size-specific clutch mass among skinks from both populations, and skinks within a population could produce larger clutches without a concomitant reduction in egg mass. Overall, compared to eggs incubated under 32 degrees C, eggs incubated under 24 degrees C could produce larger (SVL) and well-developed hatchlings with less unutilized yolks. Compared to eggs from Lishui incubated under the same temperature of 24 degrees C and 32 degrees C, eggs from Shaoguan produced hatchlings with smaller body wet mass and carcass dry mass. Accordingly, there was geographic variation in suitable range of incubation temperatures, and eggs laid by skinks from Lishui could successfully incubate in a wider range of temperatures.