11 July 2023

Plains Emerald -- new for Michigan

Plains Emerald (Somatochlora ensigera) is an attractive dragonfly found primarily west of the Mississippi River. Eastern records come from three U.S. states (Wisconsin, Indiana, and Ohio) and one Canadian province (Ontario, although there are multiple records from western Ontario and provinces further west). There are no previous Michigan records.

As part of our efforts to document the distribution of Michigan Odonata, the Michigan Department of Environment, Great Lakes, and Energy (EGLE; formerly the Department of Environmental Quality) has been sending us nymphs collected during their watershed surveys. These surveys only identify aquatic macroinvertebrates to family, so Darrin has been spending winter days identifying as many to species as possible, and we've garnered many new county-level records form these efforts. 

Several nymphs collected by EGLE's Elizabeth Stieber in August 2022 in southern Menominee County in the western Upper Peninsula were highly suggestive of Plains Emerald. Many traits, particularly measurements and ratios, were difficult to discern on these early to mid-instar individuals, so we didn't want to make a definitive call on ID. 

The nymphs went next to Anthony Cognato and Jordy Hernandez at Michigan State University for DNA sequencing as part of a larger project on Somatochlora phylogeny. Two of the nymphs were a match for Plains Emerald, based on reference material from Minnesota. DNA could not be sequenced from a third nymph. 

The two matching nymphs were from the Little River southeast of the town of Wallace, ~8 km east of the Wisconsin border. The third nymph was from Kelley Creek, northwest of the town of Birch Creek and ~5.5 km east of the Wisconsin border. The closest record of Plains Emerald to these Michigan locations is from 1988 in neighboring Marinette County, Wisconsin.

Collection site of two Plains Emerald nymphs on the Little River, Menominee County, Michigan
Photo by Elizabeth Stieber.

We will post a link to a more detailed write-up for the Argia, a publication of the Dragonfly Society of the Americas, when it's published.

This brings the Michigan checklist to 170 species based on voucher specimens.

Further reading:

Beckemeyer, R. 1998. A brief history of the Plains Emerald - Somatochlora ensigera. Argia 10:17–20.

DuBois, R. B., and K. J. Tennessen. 2008. Nymphal habitat of Somatochlora ensigera Martin (Plains Emerald). Argia 20:9–11.

Williamson, E. B. 1912. The known Indiana Somatochloras (Odonata). Entomological News 23:152–155.

Williamson, E. B. 1922. Indiana Somatochloras again (Odonata, Libellulidae). Entomological News 33:200–207.

21 March 2023

Michigan's new threatened and endangered species list

Every few years, the state of Michigan tasks various committees of experts with reviewing threatened and endangered species, as required by law. The past two cycles one of us (Julie Craves, a.k.a. Nannothemis) has been a member of the Insect Technical Advisory Committee. The committee works to form recommendations on elevations, downgrades, additions, and subtractions to the list, which then goes through a review process that includes internal review and public comment before being signed into law.

There were multiple changes made to the list of Odonata in the recommendations submitted in 2014-2015, but they were not acted upon by the state for various (mostly political) reasons. The Whitmer administration called for an update and the Committee once again revised the list, and submitted changes in September 2019. After delays related to Covid, the state list was finalized and signed into law on 20 March 2023. The entire state threatened and endangered species list including all species can be viewed here.

The Odonata list is below. On the Michigan Odonata Survey rare species webpage, we have other conservation-oriented lists of Odonata in the state.

Hine’s Emerald – Somatochlora hineana Williamson no change
Russet-tipped Clubtail – Stylurus plagiatus (Selys) – elevated from special concern
Gray Petaltail – Tachopteryx thoreyi (Hagen in Selys) – elevated from threatened

Tiger Spiketail – Cordulegaster erronea Hagen in Selys- elevated from special concern
Alleghany River Cruiser — Macromia alleghaniensis Williamson – new to list
Pygmy Snaketail – Ophiogomphus howei Bromley – no change
Elusive Clubtail – Stylurus notatus (Rambur) – elevated from special concern

Special concern (no legal protection)
Extra-striped Snaketail – Ophiogomphus anomalus Harvey
Incurvate Emerald – Somatochlora incurvata Walker
Riverine Clubtail – Stylurus amnicola Walsh
Laura’s Clubtail – Stylurus laurae Williamson

Removed from special concern
Smoky Rubyspot – Hetaerina titia (Drury)
Splendid Clubtail – Gomphurus lineatifrons (Calvert)
Rapids Clubtail – Phanogomphus quadricolor (Walsh)
Ebony Boghaunter – Williamsonia fletcheri Williamson
Ringed Boghaunter – Williamsonia lintneri (Hagen in Selys)