Technical Abstract: The effects of rearing conditions have been shown to affect several aspects of entomopathogenic nematode biology, including dispersal behavior and infectivity. The present study explores the differences in developmental-rate of Heterorhabditis bacteriophora and Steinernema carpocapsae when infective juveniles (IJs) were collected using a White trap, which is standard laboratory practice, versus when they are allowed to emerge naturally into sand. We exposed Galleria mellonella to IJ entomopathogenic nematodes that were treated in one of three ways: collected in a White trap, allowed to emerge directly into sand, or collected in a White trap and treated with a cadaver homogenate. Steinernema carpocapsae IJs developed into adults at a faster rate when they were allowed to emerge directly into sand than when they were collected by other means. The difference in development was shown not to be attributable to differential infection rates. This difference was not found in H. bacteriophora