Entomopathogenic nematodes can be mass produced in artificial media fo
r use as biological insecticides. Nematode in vitro media have been pr
imarily developed on the basis of yield without fully considering nema
tode nutritional requirements. We investigated the quality and quantit
y of lipids in the entomopathogenic nematode Steinernema glaseri when
grown in vivo in Popillia japonica (a natural host), Galleria mellonel
la (a factitious hose), and in solid and liquid media. Nematode yield
(infective juveniles per mg dry organic material) was 4 times higher i
n the in vivo compared with the in vitro cultures. Nematodes produced
in vivo using P. japonica accumulated a significantly higher amount of
lipids compared with nematodes grown using G. mellonella or in vitro
solid and liquid methods, respectively. Fractionation of S. glaseri to
tal lipids revealed that nematodes produced using P. japonica accumula
ted significantly higher phospholipids and sterols compared with other
methods. C:18 fatty acids were the predominant class of lipids in S.
glaseri irrespective of production method. In vivo-produced nematodes
had oleic 18:1 acid as the major fatty acid, whereas in vitro-produced
S. glaseri had a mixture of oleic 18:1 and linoleic 18:2 acids as the
predominant fatty acids. We conclude that the lipid composition of en
tomopathogenic nematode is host or medium dependent. We suggest that a
djusting the in vivo medium by addition of components similar to a nat
ural host nutritional composition should improve nematode production.