Tail loss affects fecundity but not offspring traits in the Chinese skink Eumeces chinensis

We used the Chinese skink Eumeces chinensis as a model animal to study the effects of tail loss on reproductive investment and offspring traits. A total of 147 wild-captured adult females were divided into four groups according to their tail conditions. Tail breaks occurred most frequently in the proximal portion of the tail and least frequently in the distal portion, with the middle portion in between. This finding suggests that tail breaks occurring in nature often entails substantial energetic costs in E. chinensis where the tail is a major site of energy storage. The proportion of females that laid eggs was higher in females with intact or completely regenerated tails than in those with broken tails. Following whole-tail autotomy, the clutch size was reduced by 17%, and the clutch mass was reduced by 14%. Females undergoing substantial tail autotomy reduced reproductive investment, and they did so by reducing the number but not the size of eggs produced. None of the egg and hatchling traits was affected by tail loss. Comparing our data with those reported for other oviparous and viviparous skinks allows us to draw two general conclusions: one is that fecundity (clutch or litter size) is affected by tail loss in all species so far studied, whereas offspring size is affected by tail loss in some species, but not in others; the other is that the reduction in fecundity following tail loss is more evident in species lacking abdominal fat bodies [Current Zoology 58 (2): 228–235, 2012].