Aquatic Insects of Michigan by Ethan Bright, Museum of Zoology Insect Division and School of Natural Resources and Environment |
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Argia (Coenagrionidae) (Dancers) of Michigan - IdentificationA very speciose New World genus of coenagrionid damselflies, most species are found in Central and South America, and many more species there remain to be described. Five species have been recorded in Michigan (see below). A. apicalis, A. sedula and A. tibialis are known only from the Lower Peninsula; the other two species - A. fumipennins violacea and A. moesta - are widespread throughout the state. These robust, short and stocky nymphs (Fig. 1) are distinguished from our other coenagrionids by large, flattened prementum that lack premental setae and have three pointed hooks (one movable hook and two pointed palpal lobes). Unlike most other coenagrionids in Michigan, Argia are principally lotic, inhabiting slow-moving sections of streams and rivers, but our species are also found in lentic habitats. A. moesta has been found along rock-margined lake sections and under rocks of stream rapids (Walker 1953), and A. apicalis, A. sedula and A. tibialis along lake shores, ponds, ditches or swamps (Westfall and May 1996). Adults tend to be medium to large-sized damselflies. Their common name pertains to the characteristic irregular manner of flight, described by Paulson (2011) as "a bouncy or jerky movement through the air quite different from the smooth forward motion of bluets, fortails, and other pond damsels and more jewelwing flight. They are much more likely to land flat on rocks, logs, or soil than other types of pond damsels, and they stay in the open, not moving slowly through vegetation as do many other pond damsels." Walker (1953) notes that they prefer alighting on bare sunny spots, and are alert, being more difficult to capture. Taxonomic References: Paulson (2011), Walker (1953) and Westfall and May (2006) Key to Adults
Mature Nymphs
References
Walker EM. 1953. The Odonata of Canada and Alaska, Volume One, Part I: General, Part II: The Zygoptera - Damselflies. University of Toronto Press, Toronto, Ontario. 292 pp. Westfall MJ, May ML. 2006. Damselflies of North America, Revised Edition. Scientific Publishers, Gainesville, Florida, USA. xii + 502 pp. Page created: 11 August 1998 - Last updated: May 19, 2020 (EB) |