The interactions of the collembolan insect Proisotoma minuta with ecto
mycorrhizal and/or pathogenic fungi was examined in three experiments:
(1) in vitro analysis of feeding patterns, (2) in vitro food preferen
ce test, and (3) in situ analysis of ectomycorrhizal colonization in r
elation to population density. The ectomycorrhizal fungi Laccaria lacc
ata, Pisolithus tinctorius, Suillus luteus, Thelephora terrestris and
the pathogenic fungi Rhizoctonia solani were employed in all experimen
ts. In vitro and in situ experiments revealed that Pr. minuta consumed
all the ectomycorrhizal fungi tested but the feeding pattern and cons
umption varied with each isolate. In a comparative in vitro feeding pr
eference test, where Pr. minuta was given a choice, R. solani was graz
ed more heavily than the ectomycorrhizal fungi. Among the ectomycorrhi
zal fungi examined, Pi. tinctorius was consumed significantly less tha
n L. laccata, S. luteus or T. terrestris in the presence of R. solani.
A 10-week in situ analysis of loblolly pine (Pinus taeda L.) seedling
root systems inoculated with Pr. minuta revealed that ectomycorrhizal
colonization was significantly less than that of control plants (with
out Pr. minuta). Collectively, these data suggest that mycophagous Col
lembola may play a major role in the distribution and biomass of ectom
ycorrhizal fungi in the rhizosphere of tree seedlings.