title: Propagation of Caenorhabditis japonica in the nest of its carrier insect, Parastrachia japonensis.
abstract: We demonstrated the disembarkation of the bacterial-feeding nematode Caenorhabditis japonica dauer larvae (DL) from adult Parastrachia japonensis female insects and observed the propagation of nematodes in artificial insect nests. Our results clarify the process of propagation in this nematode species and provide insights into the nematode-insect relationship. Quiescent C. japonica DL resumed their mobility only at > 99.9% relative humidity (RH) at 25°C in the presence or absence of the carrier insect. In artificial nests with > 99.9% RH, DL resumed their mobility and the number of DL on female insects decreased gradually after oviposition, although numerous DL remained on the insects. Very few DL were detected on mother insects after hatching. Nematode propagation was observed on the egg mass after hatching and on nymphal carcasses; the total number of nematodes in the nest increased dramatically after this point. These results indicate that humidity is an important factor for disembarkation of C. japonica DL and that C. japonica propagates in the nest of P. japonensis where it feeds on the remains of eggs and nymph carcasses, indicating that C. japonica and P. japonensis have a unique phoretic and necromenic association.
authors.affiliation: Department of Applied Biological Sciences, Faculty of Agriculture, Saga University, Japan.
authors.forename: Etsuko
authors.initials: E
authors.lastname: Okumura
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ishikawa
authors.forename: Ryusei
authors.initials: R
authors.lastname: Tanaka
authors.forename: Toyoshi
authors.initials: T
authors.lastname: Yoshiga
mesh_terms: D000818:Animals; D002107:Caenorhabditis / Q000502:physiology*; D005260:Female; D006813:Humidity; D007313:Insecta / Q000469:parasitology*; D009425:Nesting Behavior; D012098:Reproduction; D013997:Time Factors