Abstract
The present study investigated the fitness consequence of pupation site of bagworms, Thyridopteryx ephemeraeformis, on arborvitae. The abundance and survival of pupae were higher on trees with a southern exposure than on those with a northern exposure. Neither sex-ratio nor female mating success was influenced by the exposure of trees. The ratio of females per male, survival of pupae, and mating success of females all increased from the bottom to the top of arborvitae. Our results suggest that bagworm larvae may enhance their fitness by pupating in locations most suitable for pupal survival and female mating success. Because adult female bagworms can not disperse, pupation by female larvae may further influence the performance of their larval progeny, either by favouring the long-range dispersal of ballooning larvae or by providing neonates with suitable foliage nearby their site of emergence.
