Biology Reference
In-Depth Information
10.
Evolutionary Adaptation by
Alien Predators and Parasites
“In our opinion, there is no doubt that competition acts as a diversifying
evolutionary force in freshwater fish communities, intraspecifically when
other species are absent and interspecifically when they are present.The
common claim that little evidence exists for character displacement and
release is simply untenable....”
—R
OBINSON AND
W
ILSON
(1994)
The small Indian mongoose (
Herpestes javanicus
) is native to southern Asia,
ranging from Iran and Iraq in the west to China and Java in the east. In
the late 1800s and early 1900s, it was introduced to Mauritius in the
Indian Ocean; Okinawa, Fiji, and the Hawaiian Islands in the Pacific;
islands in the Adriatic Sea; many islands in the West Indies; and several
other island areas (Simberloff et al. 2000).The motivation for these intro-
ductions was a supposed role in biological control of snakes and rodents.
In its native Asian range, the small Indian mongoose shows variation
in body size and sexual dimorphism, depending on whether or not two
other species of congeneric, but slightly larger, mongooses occur in the
same area. In the easternmost part of its Asian range, these congeners are
absent and the small Indian mongoose is larger and shows greater sexual
size dimorphism, males being larger than females.
The source of populations introduced to oceanic islands was eastern
India and Bangladesh, where the small Indian mongoose is sympatric
with its congeners. An analysis of specimens from throughout the Asian
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