<p>The animals on the cover of <i>Mastering the Lightning Network</i> are wood ants (<i>Formica rufa</i>). Commonly used to describe a broad group of ants, “wood ants” are those that either construct nests in forested areas or infest wood in a home. However, <i>Formica rufa </i>specifically refers to the mound-building red wood ants that are mainly found across southern Britain, North to Mid Europe, Pyrenees, and Siberia. Sometimes, they are also found in North America in both coniferous and broad-leaf broken woodlands and parklands.</p>
<p>Also known as the southern wood ant, this subspecies of wood ants are aggressive, active, and large. The wood ant queens are typically 12-15mm, dark red and black and can live up to 15 years. Worker ants, on the other hand are slightly smaller at 8-10mmm, also dark red and black, and have a lifespan of anywhere between a few weeks to seven years depending on whether they’re male or female (males die soon after mating).</p>
<p>Capable of producing formic acid in their abdomens, red wood ants can eject it up to a few feet away when threatened by predators. Their nests are often conspicuous, dome-shaped mounds of grass, twigs, or confider needles, often built against a rotting tree stump in an area where the sunlight can reach them easily. Wood ants live in large colonies which may have 100,000 to 400,000 workers and 100 queens. Red wood ants specifically are aggressively territorial and often attack and remove other ant species from the area.</p>
<p>Red wood worker ants forage up to 50 meters from their nest to collect a natural resin found dripping from pine trees. In a behavior unique to wood ants, individual ants walk over the resin to disinfect themselves from bacteria and fungi. Additionally, they also collect and diet on aphid honeydew, small insects, and arachnids. The red wood ants are commonly used in forestry and often introduced into an area as a form of pest management.</p>
<p>The red wood ants are currently a protected species and are categorized as “near threatened” by the International Union for Conservation of Nature. Many of the animals on O'Reilly covers are endangered; all of them are important to the world. To learn more about how you can help, go to <ahref="http://animals.oreilly.com/">animals.oreilly.com</a>.</p>
<p>The cover illustration is by Karen Montgomery, based on a black-and-white engraving from a loose plate, origin unknown. The cover fonts are Gilroy Semibold and Guardian Sans. The text font is Adobe Minion Pro; the heading font is Adobe Myriad Condensed; and the code font is Dalton Maag's Ubuntu Mono.</p>
