Data from: Host cues mediate growth and establishment of oak mistletoe (Phoradendron leucarpum, Viscaceae), an aerial parasitic plant.

The oak mistletoe (Phoradendron leucarpum, Viscaceae) is well-documented
to exhibit preference for a few potential host species in a given
locality, even when many potential host species are present. In trying to
explain this distribution, we examined the mechanisms by which mistletoe
seedlings recognize potentially suitable hosts in the Piney Woods
ecoregion of east Texas. An initial survey of patterns of infection on the
campus of Sam Houston State University revealed that water oak (Quercus
nigra) was host to nearly half of the mistletoes observed, despite
comprising less than 15% of trees surveyed. Field experiments demonstrated
that light, host physiochemistry, and volatiles released from potential
host trees serve as cues affecting the viability and establishment of
mistletoe seedlings. These results provoked further study in controlled
laboratory settings, in which it was demonstrated that chemical compounds
in the bark of local host trees (compared to trees that serve as hosts
elsewhere, but not in our survey) induce significantly although slightly
greater seedling viability. Establishment of haustoria depended only on
the presence of these chemicals, regardless of host species. Importantly,
we demonstrated that three common monoterpenes, limonene, β-myrcene, and
β-phellandrene induce a positive growth response of mistletoe radicles.
These results taken together suggest a model to explain local host
preference in P. leucarpum, in which covariation between mistletoe fruit
maturity and monoterpene production by hosts determines the distribution
of successful haustorial establishment.