The distribution and abundance of entomopathogenic nematodes within an
d among sites were investigated by taking soil samples along transects
at several locations in southwestern New Jersey and by assaying for n
ematodes using the Galleria-bait method. Entomopathogenic nematodes we
re found at 12 of 13 sites (92.3%) and in 72 of 600 soil samples (12.0
%). Heterorhabditids (probably Heterorhabditis bacteriophora) were fou
nd in 60 samples from 12 sites. Steinernematids were rarer, with Stein
ernema glaseri being found in 8 samples from 3 sites, S. feltiae (=bib
ionis) in 4 samples from 2 sites, and S. carpocapsae in 2 samples from
2 sites. Heterorhabditids differed significantly in abundance among s
ites with from 0 to 47.5% of samples from individual sites proving pos
itive. Overall, heterorhabditids were equally abundant in turf and wee
dy habitats but significantly less abundant in closed-canopy forest wh
ere no positive records were obtained. Within sites, heterorhabditids
were aggregated, with individual soil samples being much more likely t
o contain sufficient nematodes to infect multiple Galleria larvae than
predicted based on the total number of positive soil samples and a ra
ndom distribution. However, this patchiness occurred on a relatively s
mall scale since the occurrences of nematodes in successive soil sampl
es taken at 4-m intervals along transects were statistically independe
nt of one another. Spatial heterogeneity is probably a fundamental asp
ect of the population biology of these species and has important ramif
ications for their population dynamics, population genetics, and commu
nity structure. (C)1994 Acodemic Press, Inc.