Determining the adaptation potential of entomopathogenic nematode multiplication of Heterorhabditis riobravus and Steinernema carpocapsae (Rhabditida: Heterorhabditidae, Steinernematidae) in larvae of Alphitobius diaperinus (Coleoptera: Tenebrionidae) and Galleria mellonella (Lepidoptera: Pyralidae).

Our objective was to determine the mean production of entomopathogenic nematodes (EPNs) infective juveniles (IJs) from Alphitobius diaperinus and Galleria mellonella larvae and the possible morphometric changes of emergent IJs. Heterorhabditis riobravus and Steinernema carpocapsae nematodes were placed on 20 larvae of each host individually located in Petri dishes, which were maintained in an environmental control chamber. After death, each larva was individually transferred to White traps where they remained for a maximum of 20 days in environmental control chambers. With IJ multiplication, the water from each trap was separately collected, emergent IJs were counted, and mean production was calculated for each host species. Relative populations of each nematode species emerging from each host were randomly selected and miscegenated. Then, 50 IJs from each host/species were randomly selected for morphometric studies. Significant difference was seen between the two EPN species for mean IJ production values from G. mellonella larvae (P = 0.0048) but not from A. diaperinus larvae (P = 0.8883). Significant differences were also seen in total body length and width between the emergent H. riobravus and S. carpocapsae IJs (P = 0.0002).