New Guide to Woodwasps of the Western Hemisphere

Includes DNA barcodes for early detection of major pests

Female S. noctilio, a species of woodwasp. Photo by Henri Goulet.

The North American forest community reacted with alarm when specimens of Sirex noctilio Fabricius were found in New York State in 2004.  Native to Europe, Asia and northern Africa, S. noctilio—a species of woodwasp in the family Siricidae—is fairly benign in its native range, but as a new arrival attacks and kills stressed but relatively healthy trees. By the time the insect showed up in North America, S. noctilio had already caused major damage to pine plantations in New Zealand, Australia, South Africa and South America.

Canadian and American authorities immediately started weekly surveys to track possible incursions of the insect into eastern North America, but they ran into a problem. Adults of S. noctilio proved difficult to distinguish from other members of the family Siricidae (woodwasps) native to North America.

Southern Research Station (SRS) scientist Nathan Schiff, David R. Smith from USDA Agricultural Research Service, and Henri Goulet from the Research Branch of Agriculture Canada decided—more or less independently—that the family needed to be revised in North America. The three started working together to provide a new guide, using many freshly caught specimens and the large collection of Siricidae specimens in the Canadian National Collection of Insects in Ottawa.  

SRS lab technician Aaron Lancaster performed many of the DNA-related processes used to identify the siricids in the guide. Photo by Nathan Schiff.

“Seventy percent of the more than 3,000 specimens in the Canadian collection were reared,” says Schiff, research entomologist with the SRS Center for Bottomland Hardwoods Research. “This provided us with a good series of specimens from known hosts, which helped us solve a lot of taxonomic problems for North American species.”

Published in the July issue of the Canadian Journal of Arthropod Identification, the 305-page identification guide they produced provides comprehensive information about siricid species of the Western Hemisphere. Worldwide there are about 122 known siricid species. In the Western Hemisphere, the family consists of seven genera and 33 described species; five of these species were introduced into the Western Hemisphere from Europe, North Africa, and Asia.   

The guide also includes DNA barcodes that Schiff developed to identify larval and adult woodwasps intercepted at ports and in survey traps used to detect new arrivals. “Prior to this study, it was impossible to tell larvae apart. DNA barcoding gives us the means to make positive identifications for these species where all the larvae look alike,” says Schiff.

For more information: Nathan Schiff at nschiff@fs.fed.us

Access the full text of the article in PDF format.

Note: the PDF version is a large file and takes some time to download. You can access the HTML version at the Canadian Journal of Arthropod Identification website.

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Posted in Forest Health Protection, Insects and Diseases, Threats