A. Peters et Ru. Ehlers, ENCAPSULATION OF THE ENTOMOPATHOGENIC NEMATODE STEINERNEMA-FELTIAE INTIPULA-OLERACEA, Journal of invertebrate pathology, 69(3), 1997, pp. 218-222
The encapsulation response of Tipula oleracea to the entomopathogenic
nematode Steinernema feltiae was investigated by exposing the insects
to nematode dauer juveniles (DJs) and by injecting DJs with and withou
t the symbiotic bacteria Xenorhabdus bovienii. The encapsulation respo
nse varied considerably between individual insect larvae. The variatio
n could not be attributed to a more or less scattered nematode invasio
n over time since it was also recorded after simultaneous injection of
a fixed DJ dose. The proportion of encapsulated nematodes declined wi
th increasing dose (injected DJs/larva) from approx 80% for 1 DJ/larva
to 33-34% for 20 DJ/larva. Tipula oleracea larvae were capable of enc
apsulating nematodes with and without symbionts inside the hemocoel; h
owever, at doses of 10 and 20 DJ/larva, axenic nematodes were encapsul
ated less frequently than monoxenic nematodes. Injected axenic nematod
es that were not encapsulated did not develop in T. oleracea larvae bu
t disappeared from the insect's hemocoel. Coinjection of symbiotic bac
teria increased encapsulation of axenic nematodes, showing that X. bov
ienii is triggering the encapsulation response of T. oleracea against
S. feltiae. (C) 1997 Academic Press.