Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada

Family Siricidae - Horntails

Tremex columba Xeris morrisoni female, dorsal - Xeris morrisoni - female Hairy wasp with yellow grasshopper mimic wasp - Tremex columba - male Urocerus albicornis - female horntail - what species? - Tremex columba Wood borer? - Urocerus albicornis empty abdominal tip, pigeon horntail wasp - Tremex columba - female
Classification
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Hymenoptera (Ants, Bees, Wasps and Sawflies)
No Taxon ("Symphyta" - Sawflies, Horntails, and Wood Wasps)
Family Siricidae (Horntails)
Other Common Names
Wood Wasps (more prominent outside of the US)
Explanation of Names
The common name of horntails refers to their abdominal spine
Numbers
2 subfamilies, with 28 spp. in 5 genera in our area and ~120 spp. in 10 genera worldwide(1)
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 (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)
FL fauna treated in(2)
Range
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)
Food
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.
Life Cycle
larval development may take 1 to 3 years to complete depending on species and climate(3).
Males emerge first and disperse, preventing inbreeding.
Remarks
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
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
Works Cited
1.Siricidae (Hymenoptera: Symphyta: Siricoidea) of the Western Hemisphere
Schiff, N.M., Goulet, H., Smith, D.R., Boudreault, C., Wilson, A.D., and Scheffler, B.E. 2012. Canadian Journal of Arthropod Identification No. 21: 305 pp.
2.The Siricidae (Hymenoptera: Symphyta) of Florida
Leavengood J.M., Smith T.R. 2013. Insecta Mundi 0309:1-16.
3.Guide to the siricid woodwasps of North America
Schiff N.M., Valley S.A., LaBonte J.R., Smith D.R. 2006. USDA Forest Service, Forest Health Technology Enterprise Team, Morgantown, WV. 101 pp.