Biology Reference
In-Depth Information
15.
Accumulation of Herbivores, Predators,
and Parasites by Alien Species
“New invaders may also act as foci for the assembly of native species that can
use them as resources. If the invasion is successful, a new invader-centered
species assemblage will be generated, and the food web complexity of the
local community will be increased.”
—C
ORNELL AND
H
AWKINS
(1993)
In 1967, 10 trees of sawtooth oak (
Quercus acutissima
) and 20 of Japanese
chestnut (
Castanea crenata
) were planted in an open field at Tall Timbers
Research Station, near Tallahassee, Florida. Although these species had
been imported to North America in the late 1800s, none were present in
the vicinity of the Tall Timbers site. In 1980 and 1981,Auerbach and Sim-
berloff (1988) censused leaf-mining insects on four trees of each species,
as well as on a series of native water oaks (
Quercus nigra
) in the same gen-
eral location.
The censuses produced 17 species of leaf-miners on both the water
oak and sawtooth oak and 15 species on the Japanese chestnut. All of the
leaf-miners found on the alien trees were found on water oaks or were
known from other oak species present at Tall Timbers.Two of the species
found on sawtooth oak and four of the species on Japanese chestnut,
however, apparently did not complete their development and emerge as
adults. This suggested that they were not fully adapted to the physiology
of these tree species. The percentage of all leaf-miners that completed
development and emerged was smallest, 7.3%, for water oak. Emergence
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