Figure 1

Life cycle of Xenos vesparum. Free living 1^st instar planidium enters a wasp nests to parasitize host larva. Upon entering the host, the planidium molts to an apodous endoparasitic 2^nd instar larva, which successively molts two additional times. The male 4^th instar larva undergoes metamorphosis through pupation (green arrow), and after, it extrudes through the abdomen of the wasp cuticle. The apolised cuticles of the larval instars form the puparium. The free-living male emerges from the puparium as a winged adult. In contrast, the 4^th instar female larva does not undergo the pupal-based metamorphic transformation but develops a cephalothorax, which is extruded through the host. The cephalothorax contains adult-specific structures that facilitate the neotenic female in insemination and the release of the planidium, and also contains glands that release pheromones to attract the male. The abdomen (abd.) and the cephalothorax (ceph.) regions in the neotenic female are marked.