Southern Spreadwing (Lestes australis)
Male Southern Spreadwing (Lestes australis), La Crosse County, WI June 4, 2018. (Copyright Dan Jackson)
This month’s DSA species’ focus is the Southern Spreadwing damselfly (Lestes australis). It is in the family Lestidae, commonly known as the “Spreadwing Family;” a family of medium to large damselflies with 152 species worldwide (Dennis Paulson, Dragonflies and Damselflies of the East). The Southern Spreadwing measures 36-46 mm (approximately 1.4 -1.8 inches) in length. As Paulson tells us, the range of these damselflies are “incompletely known,” but may be in the Northeastern and Midwestern United States, west to the western edge of the plains States, and south to Texas and eastern New Mexico, and to the middle of Florida. Read on to discover Wisconsin dragonfly expert Dan Jackson’s attempt to solve one of the mysteries of this fascinating species.
A Search for Answers in Wisconsin
The Southern Spreadwing (Lestes australis) has been a bit of a mystery both in general and in Wisconsin. Historically, there was a question as to whether this was a separate species or a subspecies of Lestes disjunctus (then Common Spreadwing and now Northern Spreadwing). More recently, there have been questions about whether the species is migratory and successfully reproduces in Wisconsin.
Bob DuBois and Ken Tennessen made the case that the species is migratory or at least completes long-range dispersal in an article published in The Great Lakes Entomologist (1). However, at that time, there wasn’t proof that the species successfully reproduces in Wisconsin.
Lestes australis was first recorded in Wisconsin by Bob DuBois in Douglas County (far northwest corner of the state) on June 26, 2002. Over the next 10 years, only a few more sightings were added with records from Monroe County on April 28, 2007; Rock County on June 15, 2008; and Manitowoc County on June 29, 2011.
Male Southern Spreadwing (*closeup) (Lestes australis), Price County, WI, May 27, 2022. (Copyright Dan Jackson)
My first experience with the species started with a misidentification. While surveying a small retention pond in Holmen (La Crosse County) on May 16, 2012, I found 10-15 males, a few females, and a couple of pairs in tandem and ovipositing. Based on my pictures and the information that was in the Wisconsin Odonata Survey (WOS) at the time, I identified them as Sweetflag Spreadwings (Lestes forcipatus) and submitted the sighting to the WOS.
My record was reviewed by Bob DuBois, and he suggested that we needed to re-check the ID. Based on the date (which was weeks before the expected flight season of L. forcipatus and L. disjunctus in Wisconsin), he suggested that it was much more likely that I had found Southern Spreadwings (L. australis). He told me that the key to an accurate ID would be the netting of pairs in tandem so that I could check the configuration of the cerci of the males and ovipositors of the females. I returned to the pond on May 18, 2012, and was able to catch a few tandem pairs. With in-hand inspection, I verified that I had in fact found Southern Spreadwings (L. australis).
From 2014 to 2020, I and other participants in the Wisconsin Odonata Survey (WOS) reported the species 38 times during the months of May and June. When found, these individuals were always completely mature, and often were seen in tandem and ovipositing. Many of my sightings were from the same pond where I had first found them in 2012 and often after a few weeks of surveying at the same location without any sign of the species. The sudden appearance of fully mature adults including sightings as early as April (including more April reports in 2023 and 2024) supports the theory that this species is migratory or at least disperses widely from locations to the south.
Ovipositing Pair of Southern Spreadwings (Lestes australis), La Crosse County, WI. June 5, 2012.
Despite repeated sightings of pairs in tandem and ovipositing, it wasn’t until 2020 that the first tentative proof of successful reproduction in Wisconsin was detected. On a survey of that same retention pond on July 24, 2020, I flushed teneral Spreadwings. I was able to catch and collect both a male and female, and the male’s cerci and the female’s ovipositor were correct for L. australis. Unfortunately, the teneral specimens did not keep well and this wasn’t 100 percent conclusive.
Teneral male Southern Spreadwing (Lestes australis) cerci, La Crosse County, WI July 24, 2020. (Copyright Dan Jackson)
(close up) Teneral male Southern Spreadwing (Lestes australis) cerci, La Crosse County, WI July 24, 2020. (Copyright Dan Jackson)
Teneral female Southern Spreadwing (Lestes australis) ovipositor, La Crosse County, WI July 24, 2020. (Copyright Dan Jackson)
On July 25, 2021, I found a teneral male Spreadwing at a pond in Jackson County Wisconsin where I had found ovipositing Southern Spreadwings in early June of the same year. Like the tenerals found in 2020, this one appeared to be a male L. australis. However, this pond also has a population of L. forcipatus, so a positive ID was again impossible with only a single specimen and no females.
Male Southern Spreadwing (*2) (Lestes australis), La Crosse County, WI June 4, 2018. (Copyright Dan Jackson)
In 2023, I was finally able to prove that Southern Spreadwings successfully reproduce in Wisconsin. When checking out a new Monroe County retention pond in early June, I found 50-plus males, females, and ovipositing pairs. Based on the late July teneral finds of the prior two years, I returned to that pond on July 13, 2022, and found teneral Spreadwings emerging that appeared to be L. australis. To add further proof, I netted and reared about 20 nymphs. Several males and females emerged, and I was able to rear them until they were sufficiently mature to verify that L. australis successfully reproduces in Wisconsin.
Female Southern Spreadwing (Lestes australis), Monroe County, WI. May 25, 2023. (Copyright Dan Jackson)
Over the past few years, the level of involvement in the Wisconsin Odonata Survey has increased dramatically. We have many more participants and many of them start surveying in April and May. As a result, the number of sightings of L. australis has increased dramatically and the species has now been reported from 22 of Wisconsin’s counties. In addition, with over 150 records, the pattern of early detection of completely mature adults—sometimes only days after the appearance of our earliest migrant dragonflies—is very well established. At least some of the Southern Spreadwings in Wisconsin are migrating here from points to the south.
The origin of the Southern Spreadwings that are found in Wisconsin—and whether individuals that emerge here return to the south—are the next big mysteries for which we need answers. Perhaps an analysis of hydrogen isotopes trapped in the wings of the early spring arrivals could shed light on this species as it did for Common Green Darners (Anax junius). The fact that later trips to the ponds where tenerals were observed did not result in sightings of any mature adults does suggest that they may have headed south. Only time, more observation, and more research will tell.
These questions and others are what make surveying and observing Odonata so much fun!
DuBois, Robert B. and Tennessen, Kenneth J. 2021. "The Puzzling Presence of Lestes australis (Odonata: Lestidae) in Wisconsin - Does This Species Migrate?," The Great Lakes Entomologist, vol 54 (1)
Dan Jackson is a native of the Coulee Region of Western Wisconsin with a lifelong passion for nature. He's an avid birder and nature photographer, the record reviewer for the Wisconsin Odonata Survey, and the Wisconsin record reviewer for Odonata Central. He is also the current treasurer and past president of the Wisconsin Dragonfly Society.
