Explanation of Names
The common name of horntails refers to their abdominal spine.
Numbers
Nearctica lists 18 species in 5 genera.
There are about 100 species worldwide.
Size
Size varies tremendously, adults of the same species may vary from 1 to 5 cm.
Identification
Both sexes have a short abdominal dorsal projection or horn that gives them their common name. Females also have an ovipositor in a sheath, placed ventrally in the abdomen.
Life Cycle
Larvae may require 1 to 3 years to complete development depending on species and climate.
Remarks
They require a symbiotic fungus to digest wood. Some are very serious pests of trees.
They have several predators and parasitoids, the most important one are the ichneumonid Megarhyssa and some nematode worms.
