Oracle PL/SQL Best Practices

Second Edition Dezember 2007
ISBN 978-0-596-51410-5
292 Seiten
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The animal on the cover of Oracle PL/SQL Best Practices, Second Edition, is a red wood ant. Red wood ants (Formica aquilonia) are often the dominant ants of forests throughout the northern hemisphere. F. aquilonia can build nest mounds of dried spruce needles and twigs that are three feet or more in diameter and height. Each nest can contain thousands of ants as well as several queens. The insects have no sting but can defend themselves by firing formic acid from their rear ends when disturbed.

The workers vary in size up to about half an inch in length with a red thorax, black abdomen, and red and black marked head. The ants are both scavengers and general predators of insects, carrying many soft-bodied caterpillars, flies, and sawflies along their several major trails back to the nest.

Red wood ants are a keystone species (i.e., without them the ecosystem changes fundamentally). When red ants disappear from a system, herbivorous insects can subsequently damage forest trees. In forests weakened by pollution and acid rain in central Europe, red wood ant populations are often endangered, which in turn causes further imbalances in predator-prey dynamics and the ecosystem. These rare ants are protected by law in some European countries because of their great value in destroying forest pests.

For 28 years, Professor Seigo Higashi has been studying a supercolony of Japanese red wood ants (Formica yessensis), which dwell along a strip of shoreline on the Ishikari coast of northern Japan. When first discovered in 1973, the colony consisted of approximately 45,000 nests with connecting tunnels extending nearly 12.4 miles along the shore of the Japan Sea. It was estimated that the colony had about 306 million workers and 1.1 million queens, and is thought to be about 1,000 years old. Since 1973, the colony has been under siege, threatened by the development of infrastructure for a new port on Ishikari Bay, which has occurred on top of 30 percent of the ant megalopolis. This has reduced the number of red wood ants living there by more than half.

The Ishikari ants are one of only two known ant supercolonies in the world. The other, smaller one is in the Swiss Jura mountains.

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