Boyeria McLachlan, 1896 - Darners

Notes - Michigan Species List - Key - References
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Page last updated: 26 October 1998 (EB)

Notes on the Michigan Species of Boyeria

Both North American species - B. grafiana and B. vinosa - are found in Michigan (see Maps 1-2, below). A late-emerging genus in our area, larvae emerge usually in late June through August. These larvae are distinctive among our other aeshnids by the conspicuous light blotch on the middorsum of the eight abdominal segment.

B. vinosa is commonly encountered in quieter sections of streams and rivers (and rarely in wave-swept portions of lakes (EB, pers. obs.) throughout Michigan, usually amongst accumulations of woody debris or organic leafy matter as well as under stones and submerged objects (Walker 1958). Williamson (1932) stated that B. vinosa "is by all odds the most abundant and most widely distributed lotic Anisoptera east of the Great Plains." Sampling from numerous localities in Michigan commonly yield two different size classes, indicating a two-year life cycle for larvae (pers. obs.). Exuviae usually are found on exposed logs and rocks as well as vegetation in and nearside the stream. B. grafiana only rarely has been collected in Michigan (Bright 1997). Along the shore of Georgian Bay, Walker (1958) found larvae along the rocky shores of inland lakes or stream rapids, and exuviae were collected "on rocks, tree trunks or boathouses near the water and the tenerals fly first to a sheltered shady spot, such as a tree trunk, branch, or a cottage verandah." Although Walker stated that B. grafiana is principally a lake species in Ontario, and usually does not occupy the same sites as B. vinosa, Perry (1977) found both species in tributaries of the Grand River in Ohio. Larvae of B. grafiana "were collected from Pierson Creek on 2 August 1974...[from] beneath small stones in the more rapidly flowing portions of the main stream. They were placed in a simulated creek-bed set up in a laboratory aquarium and supplied with living mayfly and stonefly nymphs and crane fly larvae for food. A female grafiana emerged on 13 August, 1974, followed by a male on 22 August. Another male grafiana was taken in flight above Pierson Creek on 16 August, 1974."

Michigan Species List

Map 1 Map 2
Map 1-2: County distribution of
B. grafiana (Map 1) and B. vinosa (Map 2) in Michigan
Click on map for a larger image

Map 1 - Boyeria grafiana Williamson, 1907- Ocellated Darner
Map 2 - Boyeria vinosa (Say, 1839) - Fawn Darner

Key to the Mature Nymphs of Michigan Boyeria
(References: Needham and Westfall 1955; Walker 1958; Louton 1982)

1a. Prementum width about 0.66x of its length, folded labium clear short of the posterior margin of mesocoxae (Figure 1a1); Ab5-9 with lateral spines (Figure 1a2); epiproct often cleft, clearly shorter than paraprocts (Figure 1a3); cerci of female > 0.25x length of the paraproct - B. vinosa

Fig. 1a1 Fig. 1a2 Fig. 1a3
Fig. 1a1: (12x, ventral view),
Boyeria vinosa larva, collected from the Black River, Cheboygan Co., Michigan, by the Michigan Natural Features Inventory on 25 June 1996, UMMZODO-1297.
Fig. 1a2: Ibid, (12x, lateral view).
Fig. 1a3: Ibid, (25x, dorsal view).

1b. Prementum width about 0.60x of its length, folded labium extends to posterior margin of mesocoxae, or beyond (Figure 1b1); abdominal segments 4-9 with lateral spines, those on 4 usually very minute (Figure 1b2; not always evident on earlier instars, and may be missing on some abnormal, mature specimens (see Wright 1949)); epiproct often pointed, as long as paraprocts (Figure 1b3); cerci of female < 0.25x length of paraproct - B. grafiana

Fig. 1b1 Fig. 1b2 Fig. 1b3
Fig. 1b1:
Boyeria grafiana larva, (12x, ventral view) from unknown locality, collector and date, UMMZODO-0337.
Fig. 1b2: Ibid (12x, lateral view).
Fig. 1b3: Ibid (12x, dorso-lateral view).

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Bright, E. 1997. New larval Odonata records for Michigan. Williamsonia 1(2):10.

Louton, J. A. 1982. Lotic dragonfly (Anisoptera: Odonata) nymphs of the southeastern United States: identification, distribution and historical biogeography. Ph.D. thesis, University of Tennessee, Knoxville. 357 + xvii.

McLachlan, R. 1896. A new name for Fonscolombia (pre-occupied). Annals and Magazine of Natural History (6)17:424.

Needham, J. G. and M. J. Westfall, Jr. 1955. A Manual of the Dragonflies of North America (Anisoptera). University of California Press: Berkeley, California. xii + 615 pp.

Perry, T. E. 1977. Boyeria grafiana, a rare Ohio dragonfly (Odonata: Aeshnidae). Great Lakes Entomologist 10:159-161.

Say, T. 1839. Descriptions of new North American neuropterous insects and observations on some already described by (the late) Th. Say. Journal of the Academy of Natural Science of Philadelphia 8:9-46.

Walker, E. M. 1958. The Odonata of Canada and Alaska, Vol. 2. University of Toronto Press: Toronto. xii + 318.

Williamson, E. B. 1907. Two new North American Dragonflies (Odonata). Entomological News 18:1-7.

Williamson, E. B. 1932. Dragonflies collected in Missouri. University of Michigan Museum of Zoology, Occasional Paper 240. 40 pp.

Wright, M. 1949. Notes on nymphs of the dragonfly genus Boyeria. Journal of the Tennessee Academy of Science 24(3):213-215.

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