Despite the warning colors, Horntail wasps are generally non-aggressive and (one source says) harmless. Both genders of Horntail Wasp species have short spines at the tip of their abdomen, but females appear to have two menacing stingers. The thicker, longer one is actually an ovipositor. The ovipositor is a tube used by the female to directly inject eggs into tree trunks and other durable wood where they are less likely to found and eaten by other insects. That sturdy spine aids in splitting the wood before the eggs are laid.
Larvae hatch inside the wood and tunnel through it, emerging as adults. Despite the great efforts to use deep wood to protect the Horntail larvae, they are eaten by the larvae of other parasitic wasps that have also hatched in the same tree. Those that survive emerge from the tree in adult form. If the tree has been harvested and used for building material before then, it is not unusual to see these adults inside as they come out of wood. Adults drink nectar and water.
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