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The animal on the cover of Oracle PL/SQL Best Practices 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 1/2 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 ...