Temperature Effects on Heterorhabditis megidis and Steinernema carpocapsae Infectivity to Galleria mellonella.

The effect of temperature on the infection of larvae of the greater wax moth, Galleria mellonella, by Heterorhabditis megidis H90 and Steinernema carpocapsae strain All, was determined. For both species, infection, reproduction, and development were fastest at 20 to 24 degrees C. Infection by both H. megidis and S. carpocapsae occurred between 8 and 16 degrees C; however, neither species reproduced at 8 degrees C. Among the nematodes used in experiments at 8 degrees C, no H. megidis and very few S. carpocapsae developed beyond the infective juvenile stage. Compared with H. megidis, S. carpocapsae invaded and killed G. mellonella larvae faster at 8 to 16 degrees C. By comparing invasion rates, differences in infectivity between the two nematode species were detected that could not be detected in conventional petri dish bioassays where mortality was measured after a specified period. Invasion of G. mellonella larvae by H. megidis was faster at 24 than at 16 degrees C.