Other Common Names
Wood Wasps (more prominent outside of the US)
Explanation of Names
The common name of horntails refers to their abdominal spine
2 subfamilies, with 28 spp. in 5 genera in our area and ~120 spp. in 10 genera worldwide(1)
Size varies tremendously: adults of the same species may vary from 1 to 5 cm
Mesonotum not divided by a transverse groove between bases of fore wings. Protibia with 1 apical spur. Last tergum of female and last sternum of male each with apical, median, cylindrical projection with concave tip. Pronotum in lateral view with a horizontal dorsal surface and with a vertical, concave anterior surface; pronotum in dorsal view with posterior margin strongly concave, with medial length about one-third lateral length.
Both sexes have a short abdominal dorsal projection (horn) that gives them their common name. Females also have an ovipositor in a sheath, placed ventrally in the abdomen.
Color is useful in identification.
Keys to genera and spp. in(1)
forests of the Northern Hemisphere south to Cuba, n. Central America, India, New Guinea, and n. Africa (2 spp. are known from tropical Africa)(3)
Wood (Tremicinae mostly on hardwoods; Siricinae, on conifers); larvae require a symbiotic fungus to digest wood(3)
. It is a complex interaction between three organisms: the wood wasp, a symbiotic wood-decaying fungus, and the host tree.
larval development may take 1 to 3 years to complete depending on species and climate(3)
Males emerge first and disperse, preventing inbreeding.
Some are serious pests of trees and spread as larvae with lumber trade.
The most important predators and parasitoids are the ichneumonid wasp Megarhyssa
and some nematodes. Others include Ibalia
Horntails do not sting: what looks like a sting is the ovipositor the female uses to lay eggs in wood
Females more abundant than males
Adults fly mostly in bright sunshine