"New" state record: Western Red Damsel (Amphiagrion abbreviatum)

The conundrum of red damsels in the genus Amphiagrion has been going on for years. Are there two species (Eastern - A. saucium, and Western - A. abbreviatum)? Or is there a third species (A. 'mesonum') as was thought by Leonora "Dolly" Gloyd? Or is it all one species, with a cline from west to east? 

Pair of Eastern Red Damsels (Amphiagion saucium), Livingston Co., MI

 

Montgomery (1943) noted that Eastern and Western "forms" could not be properly assigned to species, and somewhat arbitrarily designated all red damsels from northwestern Indiana as Western and the rest of the state as Eastern. Kormondy (1957) commented on a "zone of overlap" between the Eastern and Western forms, gave some measurements, but concluded that morphological features were more important than measurements. O'Brien (1999) brought up Gloyd's unfinished work on the third species and said Michigan had what appeared to be intermediate forms; he lumped all Michigan records into Eastern Red Damsel for the purposes of the Michigan Odonata Survey. Donnelly (2001) lamented that many records from the Great Plains were simply assigned to Western Red Damsel without examination and reiterated that the taxonomy of Amphiagrion was not resolved. Daigle and Pilgrim (2014) attempted to tackle the problem with DNA (but did not specify methods such as which gene regions were used) and concluded that Western Red Damsels occur to the Indiana/Ohio border...but that red damsels from western Ohio, Michigan, and Tennessee were identical genetically to those from New York and Vermont.

This is by no means a complete bibliography of thoughts published on this topic. Ken Tennessen has worked up color and morphology differences based on nearly 200 individuals (unpublished, pers. comm.). We've contributed to that effort by looking at dozens specimens at the University of Michigan Museum of Zoology (UMMZ) and Michigan State University, including many that Gloyd identified as A. 'mesonum' (her manuscript and notes on how she came to these conclusions has not been found). 

We utilized Ken's latest matrix of 2 color features, 7 measurements, and 1 structural characteristic -- some are a bit subjective and a few overlap. We determined that there were some Michigan vouchers that are strong enough candidates to be called Western Red Damsel, and so we have added this species to the Michigan checklist.

 

First, we found 4 males collected in July 1973 in Houghton County by John Perona. They were in his large collection of mostly Lepidoptera donated to the Albert J. Cook Arthropod Research Collection at Michigan State University. It included many pinned Odonata of which a large portion were unidentified; as curators of this part of the MSU collection, we have worked through the Perona material to identify, catalog, and database the Michigan Odonata.

 

One of the Western Red Damsels from the Perona collection at Michigan State University.

Another collection we have been working to incorporate into the MOS database is at the Florida State Collection of Arthropods (FSCA) in Gainesville. The Odonata collection is not digitized nor do the items have catalog numbers. Earlier this year a student, Anisha Sapkota, was hired to photograph all the adult Michigan Odonata and assign catalog numbers (more on this project in a future post). We reviewed the daily output for those we wanted to obtain on loan. This was one of those items:

 

These 4 males from Baraga County were initially identified as the Eastern Red Damsel, but then changed -- we assume by collector Sid Dunkle -- to Western Red Damsel. We confirmed the latter identification. 

 

While the eight males above seem to be the best fit for Western Red Damsel, additional work needs to be done to shed light on the distribution of Amphiagrion across North America and in particular in the middle of the U.S. There are not enough recent specimens to work with, particularly from the Great Plains, western Great Lakes, and Ohio River Valley. And specimens will be necessary to take meticulous measurements of various parts of these tiny insects, and to have the material to do additional DNA work utilizing multiple genetic regions.

 

We are currently working on pulling this project together. 

Literature cited:

 

Daigle, Jerrell J. and Erik Pilgrim. 2014. Amphiagrion (red damsel) update. Argia 26(1):19. 

 

Donnelly, Nick. 2001. Taxonomic problems with North American odonata species - a last appeal for information. Argia 13(2):5-10. 

 

Kormondy, Edward J. 1957. Records of western Odonata with notes on Amphiagrion abbreviatum (Selys). Journal of the Kansas Entomological Society 30 (3): 108-110.

Montgomery, B. Elwood. 1943. The Distribution and Relative Seasonal Abundance of the Indiana Species of Agrionidae (Odonata-Zygoptera). Proceedings of the Indiana Academy of Science, 53:179-185.

O'Brien, Mark F. 1999. Changes to the 1999 Michigan Odonata list. Williamsonia 3(2):4-5.