NC State University Insect Museum

Odonata: Anisoptera: Petaluridae: Tachopteryx thoreyi

(written by Ann Carr, with input from Andy Deans)

Tachopteryx thoreyi, commonly known as the grey petaltail, is a dragonfly species in the family Petaluridae – the smallest family in Odonata, with only five genera and 10 species worldwide. The Australian species Petalura gigantea happens to be the world’s largest extant dragonfly. T. thoreyi is currently the only described species in the genus Tachopteryx and was discovered in the United States and described in 1857 by Hagen.

The Grey Petaltail dragonfly is large species ranging from 7.1-8.2cm in length. The species also has a characteristic grey and black patterned abdomen. The Grey Petaltail’s distribution is mainly restricted to the east coast, ranging from New York to eastern Texas, southeast to Florida. Adults are usually found in deciduous forests, around seeps and marshy areas. Proximity to semi-aquatic habitats is important for the maturation of naiads. Petaluridae vary from other dragonfly families in that their naiads are not truly aquatic. The naiads instead are found in muddy, mossy, vegetative areas that contain minimal amounts of standing water. Being associated with a somewhat aquatic environment does make the species susceptible to water quality, and thus they are potentially endangered by irresponsible logging and clearing.

Adults are typically found on tree trunks and will occasionally land on people wearing neutral-colored clothing. Males will fly up and down tree trunks in search of mates. Tachopteryx thoreyi reproduce by means of an indirect copulation wheel and the production of a spermatophore by males. Males produce this sperm package and place it onto a secondary reproductive organ on their ventrum. Once a female has been clasped around the head, she will reach her abdomen up and collect the spermatophore, fertilizing herself with the male’s secondary genitalia.

Both the adults and immatures are predators on other insects. The species is equipped with large eyes for finding prey and strong mandibles for devouring them. The Insect Museum is currently home to two preserved adults and one immature specimen. The naiad (from 1927) and one of the adult specimens (from 1916) were both collected in Raleigh, NC. The other adult (from 1969) was collected in Perry Hall, MD. The best method for catching this dragonfly is by quietly stalking with a large sweep net. T. thoreyi is most active during months of April-July, though they occur most commonly in June in the Piedmont region of North Carolina. Adult specimens should be pinned (as for all dragonflies). For collecting naiads, sweeping with a D-net in marshy, mossy, or muddy areas will suffice. These specimens should be stored in alcohol and labeled appropriately.

Find out more:

Giant Dragonfly (Petalura gigantea) (2008). Wingecarribee. Retrieved November 30, 2009. http://www.uow.edu.au/~sharonb/wingecarribee/value/dragonfly.html

Species Tachopteryx thoreyi (2004). BugGuide. Retrieved November 30, 2009. http://bugguide.net/node/view/4019

Grey Petaltail (2004-2005). New York Natural Heritage Program. Retrieved November 30, 2009. http://www.acris.nynhp.org/guide.php?id=8177

Tachopteryx thoreyi (2007). Michigan Natural Features Inventory. Retrieved November 30, 2009. http://web4.msue.msu.edu/mnfi/explorer/species.cfm?id=12061

Petaluridae: Petaltails; Graybacks (1998). Discover Life. Retrieved November 30, 2009. http://www.discoverlife.org/20/q?search=Petaluridae