Predatory behavior of a nematode is usually determined through gut content observation or prey delimitation
counts. In this experiment, Mononchus and Neoactinolaimus predation of Rotylenchulus reniformis or
Meloidogyne incognita was determined using a PCR-based nematode gut content analysis. Soil samples
naturally infested with Mononchus were placed in tubes and potential prey nematodes R. reniformis, M.
incognita, or a mixture of both were introduced. The gut contents of Mononchus were assayed for the
DNA from R. reniformis or M. incognita using PCR specific primers. A higher % of Mononchus tested positive
for DNA of R. reniformis than for M. incognita when the prey were added alone. However, when provided
with both prey species, Mononchus was tested positive for DNA of M. incognita more frequently than for R.
reniformis. Percent Mononchus testing positive for DNA of R. reniformis correlated positively with the abundance
of R. reniformis, but this relationship was not observed between Mononchus and M. incognita.
Neoactinolaimus was added to aqueous solution containing a mixture of free-living nematodes and R. reniformis.
More Neoactinolaimus tested positive for DNA of R. reniformis than other predatory or omnivorous
nematodes in the same samples. Based on regression analysis, the presence of fungivorous and other
predatory nematodes in the soil could distract Neoactinolaimus from predation on R. reniformis. Our results
suggested that Prismatolaimus, Mesodiplogasteroides and Eudorylaimus could also prey on R. reniformis.
Although less than 40% of the predatory or omnivorous nematodes tested preyed on R. reniformis, this level
of predation could contribute to reducing the population densities of plant-parasitic nematodes in the soil.
Published by Elsevier Inc.