Aquatic Insects of Michigan
by Ethan Bright, Museum of Zoology Insect Division and School of Natural Resources and Environment
Petaluridae (Petaltails) of Michigan
Petaluridae is almost exclusively an amphi-Pacific taxon, with 10 species in 5 genera distributed almost exclusively around the Pacific rim. Only Tachopteryx thoreyi (Hagen), which is widely distributed in eastern and southeastern North America, does not fit this distribution. Only two closely-grouped records in the extreme southwestern part of Michigan are known. Probably due to the difficulty in finding the correct habitat and individual nymphs themselves, larval specimens have not yet been collected from these sites. (Based on adult collections, the population appears stable). The rarity of records in Michigan probably is an artifact of its geographical range; until more information is known about this species from these sites, this dragonfly deserves the special concern status in Michigan. Nymphs probably require at least 3 or more years before maturity, based on information from the references below.
Both adults and nymphs contain morphological characters considered phylogenetically primitive. Nymphs are distinctive for their thick, hairy antennal segments, thick and slightly concave prementum, palpal lobes with a large spur at the base of the movable hook, and construction by nymphs of burrows in bogs and wetland seepages. Although this burrowing habit in mud or peat appears to be shared by most members of the family (Williamson 1932, Svihla 1959, Taketo 1971, Rowe 1987), Dunkle (1981) was unable to locate such burrows for Tachopteryx thoreyi nymphs in permanent spring-fed hillside seeps near Gainesville, Florida. Here nymphs were "found...between or under wet leaves near the uphill edges of seeps. They were usually in a thin slowly flowing layer of water, but some were above the water surface. A few were in depressions in the soil, but none were in burrows..." The forested seeps described by Dunkle probably represents the most likely habitat for nymphs to be found in Michigan.
Nymphs of some species may be considered semiterrestrial (their rectal chambers can also utilize air), often lying at the edges of their burrows above water in wait for prey. The lower part of the burrow is usually submerged in well-oxygenated water, the upper region - often an excavated trough or leading up to vegetation - exposed to muck or air. Extended periods of exposure - from hours to even weeks - to air has been observed for Tanypteryx hageni (Svihla 1959), Tanypteryx pryeri (Taketo 1971) and Uropetela spp. (Rowe 1987). Indeed, these authors consider these nymphs as air-breathers, with Rowe suggesting the rectal chamber in the abdomen functioning as a "reverse aqualung." Foraging activity (lie-in-wait ambushing) is mostly nocturnal, although specimens in captivity have been observed in this position during daylight hours (Rowe 1987). Apparently terrestrial arthropods are the principal prey; feeding behavior has been noted by various authors (Meyer and Clement 1978, Dunkle 1981, Rowe 1987).
Meyer R P, Clement SL. 1978. Studies on the biology of Tanypteryx hageni in California. Annals of the Entomological Society of America 71(5):667-669.
Rowe R. 1987. The Dragonflies of New Zealand. Auckland University Press, New Zealand. 260 pp.
Svihla A. 1959. The life history of Tanyopteryx hageni Selys (Odonata). Transactions of the American Entomological Society 85:219-232.
Taketo A. 1971. Studies on the life-history of Tanypteryx pryeri Selys (Odonata, Petaluridae). II. Habitat and habit of the nymph. Kontyu 39:299-310.
Williamson EB. 1932. Dragonflies collected in Missouri. Occasional Papers of the Museum of Zoology, University of Michigan 247. 40 pp.
Page created: August 9, 2003; Last edited: November 10, 2013 (EB)