Nutrients intake determines the post-maturity molting in the golden orb-web spider Nephila pilipes (Araneae: Nephilidae)

While molting occurs in the development of many animals especially in arthropods, postmaturity molting (PMM, organisms continue to molt after sexual maturity) has received little attention. Mechanism of molting has been studied intensively, however, the mechanism of PMM remains unknown although it is suggested to be crucial for the development of body size. In this study, we investigated factors that potentially induce PMM in the golden orb-web spider Nephila pilipes, which has the greatest degree of sexual dimorphism among terrestrial animals. We manipulated the mating history and the nutrient consumption of the females to examine whether they can affect PMM. The results showed that female spiders under low nutrition were more likely to molt as adults, and mating had no significant influence to the occurrence rate of PMM. Moreover, spiders that experienced PMM lived longer than those without and their body sizes were significantly increased. Therefore, we concluded that it is the nutritional condition rather than the mating history that has affected PMM. KEY WRODS: Arthropod development, Nephila pilipes, Nutrients intake, Orb-web spider, Polyandry, Post-maturity molting Jo ur na l o f E xp er im en ta l B io lo gy • A dv an ce a rt ic le