Submitted to: Journal of Nematology
Publication Type: Abstract Only
Publication Acceptance Date: July 6, 1999
Publication Date: December 1, 1999
Citation: Marti, O.G., Timper, P. 1999. Phoretic relationship between a Bacillus sp. and the entomopathogenic nematode, Heterorhabditis sp.[abstract]. Journal of Nematology. 31:553. Technical Abstract: During a survey to identify native species of entomopathogenic nematodes, we exposed Galleria mellonella larvae to soil samples collected from fields and pastures near Tifton, GA. Unidentified species of Heterorhabditis and Steinernema were found. In four of eight collection sites, we observed sporangia of an unidentified Bacillus sp. frequently attached to the sheath hof infective juveniles of Heterorhabditis sp. that had emerged from Galleria exposed to soil. Sporangia were spindle-shaped, 9-11 um in length, and contained a central refractile endospore. They differed from published descriptions of B. popilliae. Sporangia were observed either loosely attached by one end to the nematode or more securely attached in a manner resembling that of Pasteuria. Numbers of sporangia attached to individual nematodes varied from zero to more than 100. This Bacillus sp. has been maintained in vivo for several months in the laboratory by exposing Galleria larva to sporangia-bearing Heterorhabditis juveniles. Large numbers of mature and developing sporangia occur in Galleria cadavers and become attached to infective juveniles of Heterorhabditis as these migrate out of the cadaver. No evidence of pathogenicity to the nematode has been found, although there may be competition between Bacillus sp. and Photorhabdus for resources in the insect cadaver. The relationship between Bacillus sp. and Photorhabdus for resources in the insect cadaver. The relationship between Bacillus and Heterorhabditis seems to be phoretic and serves to spread the sporangia beyond the immediate vicinity of the insect cadaver.