Life History of Eudiplogaster Aphodii (Rhabditida: Diplogasteridae), a Facultative Parasite of Aphodius Fimetarius (Coleoptera: Scarabaeidae)

Abstract

The life history of Eudiplogaster aphodii (Bovien) (Rhabditida: Diplogasteridae), a facultative parasite of Aphodius fimetarius (L.) (Coleoptera: Scarabaeidae) was investigated. Third stage infective juveniles of E, aphodii enter the mouth of second and third stage beetle larvae. After penetrating through the host's midgut, the nematodes begin developing in the hemocoel. The nematodes continue to grow as they are carried through the pupa and into the adult stage uf the host. At the time of emergence, when the hosts are ovipositing in dung, the nematodes have approximately doubled in length and width. After leaving the adult beetles, the nematodes molt, mate, and reproduce in the dung. As the substrate begins to dry, third stage infective juveniles are formed. Adult nematodes arising from juveniles taken from beetle hosts possess short tails, whereas second generation adults arising from juveniles taken from agar plates have long filiform tails. This morphological variation in E. aphodii, together with its ability to enter healthy beetle larvae, are unusual characteristics of this nematode.