Orientation of some Heterorhabditis bacteriophora (Poinar, 1976) (Rhabditida: Heterorhabditidae) strains to Lolium perenne L. (Poales: Poaceae) and Galleria mellonella (L., 1758) (Lepidoptera: Pyralidae)

Abstract

Entomopathogenic nematodes (EPNs) have different host-finding (foraging) behavior that varies from species to species. Besides their foraging behavior, the orientation of some EPNs can vary depending on plant roots. In the present study, the orientation of some Heterorhabditis bacteriophora (Poinar, 1976) (Rhabditida: Heterorhabditidae) strains to perennial ryegrass Lolium perenne L. (Poales: Poaceae) roots and greater wax moth Galleria mellonella (L., 1758) (Lepidoptera: Pyralidae) larvae were investigated. For this purpose, three different strains of H. bacteriophora were used. One of them was a hybrid strain (HBH) and the two were parents (HB1138 and HB4) of the hybrid strain. Three experimental combinations were conducted in the study conducted in 2019 under laboratory conditions in Bursa, Turkey: (A) plant roots, larvae and control; (B) plant roots, control I and control II; and (C) mechanically damaged plant roots, control-I and control-11 in Y-tube olfactometers filled with moist sand. The results indicated that for combination A, most orientation to plants and larvae was seen in HB1138; for combination B, most orientation to plant roots was was seen in HBH; and for combination C, strain HB4 showed the most orientation to mechanically damaged plant roots. According to the results, each strain of the same EPN species may have a different response to plant roots and host insects.