PUTERBAUGH, MARY N. Allegheny Institute of Natural History, University of Pittsburgh at Bradford, Bradford, PA 16701. - Preliminary investigation of the interaction between the liverwort Frullania eborascensis and Bdelloid rotifers.
Bryophyte and invertebrate interactions abound, but they are poorly
understood. I examined the frequency of Bdelloid rotifers within
lobular-shaped leaves of an epiphytic liverwort (Frullania
eborascensis) in northwestern Pennsylvania. Liverworts were
randomly sampled from the bark of three neighboring streamside trees
from July through September, 2000. Between 13-68% of the lobules on
any given plant were occupied by rotifers (mean=30%; N = 34 samples;
5054 lobules). Of occupied lobules, 71% contained one rotifer, 20%
two, and 9% three or more. This distribution is significantly
different from that expected at random (Chi-square test using
Poisson distribution for expected values, P<0.0001). Although
further analyses are needed to confirm this conclusion, the excess of
lobules with multiple rotifers supports the hypothesis that rotifers
reproduce within lobules and that the plant-animal interaction could
have fitness consequences for the rotifer. In addition to this
finding, I also show that estimates of rotifer abundance within
lobules decreased 20% within three days of sample collection,
suggesting that accurate estimates of occupied lobules need to be
taken soon after sample collection and that rotifers may be dying as
the liverwort dries out.
Key words: Bdelloid rotifers, bryophyte-invertebrate interaction, Frullania eborascensis, liverwort, plant-animal interaction