Infectivity and post-infection development of infective juveniles originating via endotokia matricida in entomopathogenic nematodes

Abstract

Infectivity and post-infection development were investigated at 25°C for infective juveniles (IJs) which originated via endotokia matricida in hermaphrodites and/or female adults of the entomopathogenic nematodes, Heterorhabditis bacteriophora, Steinernema glaseri and S. carpocapsae. The IJs spontaneously emerging out of larval cadavers of Galleria mellonella were designated as normal IJs and used as comparison. Nematode invasion was the most prompt and numerous for normal IJs, followed by IJs produced via endotokia matricida in the 1st, 2nd, and 3rd generation adults of the three nematode species examined. Post-infection development and reproduction of nematodes also occurred more promptly and numerously when inoculation was made with normal IJs. The insecticidal activity of IJs originating from endotokia matricida was inferior to that of normal IJs which retained a significantly higher density of symbiotic bacteria than the former IJs of the respective nematode species. The IJs reproduced in and emerged out of host cadavers showed similar pathogenicity and bacterial retention, irrespective of the origin of the IJs used as inocula.