Hine's Emerald

The life cycle of Hine’s emerald dragonfly is similar to most dragonflies in that it is comprised of the following stages: aquatic egg, aquatic larva and a terrestrial / aerial adult as described by Corbet in 1962. A Hine’s emerald dragonfly female will most likely lay more than 500 eggs during her life noted D. Soluk, with the Illinois Natural History Survey in 1999. After an egg is hatched, the larvae may spend 2 to 4 years in small streamlets, foraging and molting as they grow, noted Soluk and others in 1996 and again in 1998. Upon completion of larval development, the larvae begin to emerge as adults, possibly as early as late May in Illinois and late June in Wisconsin, and continue to emerge throughout the summer noted Vogt and Cashatt in 1994 and others in the late 1990s. The first emergence date can be estimated using temperature and precipitation data documents Mierzwa and others in 1995. The Hine’s emerald dragonfly’s known flight season lasts up to early October in Illinois, as documented by Vogt and Cashatt in 1994, and later by Soluk and others in 1996. Populations in Wisconsin were documented by Vogt and Cashatt to have flight season through late August. Soluk and others documented in 1996 that fully adult Hine’s emerald dragonflies can live at least 14 days, and Mierzwa and others documented that they may live four to six weeks. As with most dragonflies, adult Hine’s emerald dragonflies feed, establish territories, mate and oviposit, or lay eggs as observed by Corbet in 1962. Most dragonfly adults are general predators throughout their entire life cycle, feeding primarily on insects they can capture while flying.

Larval life history

D. Soluk observed in a laboratoryenvironment with both Williamson's emerald dragonflies (Somatochlora williamsoni) and a small number of Hine’s emerald dragonflies, that the Hine’s emerald dragonfly was assumed to be a sit-and-wait predator. Johnson also noted in 1991, that Hine's emerald dragonflies remain motionless until a prey item comes within striking range. Pintor and Soluk of the Illinois Natural History Survey analyzed larval behavior using time lapse video and infrared light observed that Hine’s emerald dragonfly larvae are much more active at night than during the day. Hine’s emerald dragonfly larvae have also been observed crawling around in streamlets at night, as documented in 1998 by Mierzwa and others. Mobility at night may reduce predation risks. It is also possible that Hine’s emerald dragonfly is an active predator, and the observed larvae were in search of prey items. 

Preliminary analyses of fecal pellets from Hine’s emerald dragonfly larvae indicate this species feeds on oligochaetes and larval mayflies and caddisflies, which are common in its habitat, as documented by Soluk and others in 1998. Soluk also directly observed larvae in containers and noted that Hine’s emerald dragonfly will attack and consume mayflies, isopods and smaller larvae of a related species, Somatochlora williamsoni.  Dragonfly larvae commonly feed on smaller insect larvae, including mosquito and dragonfly larvae, worms, small fish and snails, as noted by Pritchard in 1964 and others as studies continued into the 1980s and 1990s. As larvae grow, it is likely their prey items or prey size change. It is probable that Hine’s emerald dragonfly is an opportunistic predator and does not rely on certain prey items for its diet.

Hine’s emerald dragonfly larvae can occur in small clusters within their habitat, noted by Soluk and others in the 1990s. Sample sizes of 1 square-foot have yielded different-size classes of Hine’s emerald dragonfly individuals and up to 28 newly-hatched larvae as Mierzwa and others documented. Single individuals have also been collected from numerous 1 square-foot samples.  The pattern of distribution is unknown; however, these data imply that Hine’s emerald dragonfly can coexist in clusters or remain independent. Soluk and others also noted in 1996 that the quality of substrate may influence larval distribution within a site.

Soluk and others documented in 1998 that Hine’s emerald dragonfly larvae may become less active, and or crawl, into tight spaces during cooler water temperatures in the late fall to early spring. Collectors have generally been unsuccessful in finding any Hine’s emerald dragonfly larvae in streamlets during this time, even in streamlets that previously contained larvae. Hine’s emerald dragonfly larvae have been located during this season by pumping water out of crayfish burrows. Soluk and Pintor noted in 1999 an instance of a single burrow containing as many as 21 larvae.  This overwintering behavior and possible shift in habitat is an important aspect of the larval life history that should be studied further.

Another interesting aspect of larval ecology is the ability to withstand drought conditions. Soluk and others documented in 1998 that Hine’s emerald dragonfly larvae have been found under discarded rail road ties embedded in a dry streamlet channel in Illinois. In Wisconsin, Hine’s emerald dragonfly larvae were collected from moist streamlets and hummocks that had little to no surface water, also observed by Soluk and others in 1998. The larval habitat in both Illinois and Wisconsin has dried up in the summer months during different years, and rainfall amounts in both Will County, Illinois and Door County, Wisconsin, show similar drought frequencies, noted Soluk and others in 1998, noting that Hine’s emerald dragonfly larvae may be adapted to survive drought conditions. 

The life cycle of Hine’s emerald dragonfly is similar to most dragonflies in that it is comprised of the following stages: aquatic egg, aquatic larva and a terrestrial / aerial adult as described by Corbet in 1962. A Hine’s emerald dragonfly female will most likely lay more than 500 eggs during her life noted D. Soluk, with the Illinois Natural History Survey in 1999. After an egg is hatched, the larvae may spend 2 to 4 years in small streamlets, foraging and molting as they grow, noted Soluk and others in 1996 and again in 1998. Upon completion of larval development, the larvae begin to emerge as adults, possibly as early as late May in Illinois and late June in Wisconsin, and continue to emerge throughout the summer noted Vogt and Cashatt in 1994 and others in the late 1990s. The first emergence date can be estimated using temperature and precipitation data documents Mierzwa and others in 1995. The Hine’s emerald dragonfly’s known flight season lasts up to early October in Illinois, as documented by Vogt and Cashatt in 1994, and later by Soluk and others in 1996. Populations in Wisconsin were documented by Vogt and Cashatt to have flight season through late August. Soluk and others documented in 1996 that fully adult Hine’s emerald dragonflies can live at least 14 days, and Mierzwa and others documented that they may live four to six weeks. As with most dragonflies, adult Hine’s emerald dragonflies feed, establish territories, mate and oviposit, or lay eggs as observed by Corbet in 1962. Most dragonfly adults are general predators throughout their entire life cycle, feeding primarily on insects they can capture while flying. 

Larval Life History

D. Soluk observed in a laboratory environment with both Williamson's emerald dragonflies (Somatochlora williamsoni) and a small number of Hine’s emerald dragonflies, that the Hine’s emerald dragonfly was assumed to be a sit-and-wait predator. Johnson also noted in 1991, that Hine's emerald dragonflies remain motionless until a prey item comes within striking range. Pintor and Soluk of the Illinois Natural History Survey analyzed larval behavior using time lapse video and infrared light observed that Hine’s emerald dragonfly larvae are much more active at night than during the day. Hine’s emerald dragonfly larvae have also been observed crawling around in streamlets at night, as documented in 1998 by Mierzwa and others. Mobility at night may reduce predation risks. It is also possible that Hine’s emerald dragonfly is an active predator, and the observed larvae were in search of prey items.  

Preliminary analyses of fecal pellets from Hine’s emerald dragonfly larvae indicate this species feeds on oligochaetes and larval mayflies and caddisflies, which are common in its habitat, as documented by Soluk and others in 1998. Soluk also directly observed larvae in containers and noted that Hine’s emerald dragonfly will attack and consume mayflies, isopods and smaller larvae of a related species, Somatochlora williamsoni. Dragonfly larvae commonly feed on smaller insect larvae, including mosquito and dragonfly larvae, worms, small fish and snails, as noted by Pritchard in 1964 and others as studies continued into the 1980s and 1990s. As larvae grow, it is likely their prey items or prey size change. It is probable that Hine’s emerald dragonfly is an opportunistic predator and does not rely on certain prey items for its diet. 

Hine’s emerald dragonfly larvae can occur in small clusters within their habitat, noted by Soluk and others in the 1990s. Sample sizes of 1 square-foot have yielded different-size classes of Hine’s emerald dragonfly individuals and up to 28 newly-hatched larvae as Mierzwa and others documented. Single individuals have also been collected from numerous 1 square-foot samples. The pattern of distribution is unknown; however, these data imply that Hine’s emerald dragonfly can coexist in clusters or remain independent. Soluk and others also noted in 1996 that the quality of substrate may influence larval distribution within a site.

Soluk and others documented in 1998 that Hine’s emerald dragonfly larvae may become less active, and or crawl, into tight spaces during cooler water temperatures in the late fall to early spring. Collectors have generally been unsuccessful in finding any Hine’s emerald dragonfly larvae in streamlets during this time, even in streamlets that previously contained larvae. Hine’s emerald dragonfly larvae have been located during this season by pumping water out of crayfish burrows. Soluk and Pintor noted in 1999 an instance of a single burrow containing as many as 21 larvae.  This overwintering behavior and possible shift in habitat is an important aspect of the larval life history that should be studied further. 

Another interesting aspect of larval ecology is the ability to withstand drought conditions. Soluk and others documented in 1998 that Hine’s emerald dragonfly larvae have been found under discarded rail road ties embedded in a dry streamlet channel in Illinois. In Wisconsin, Hine’s emerald dragonfly larvae were collected from moist streamlets and hummocks that had little to no surface water, also observed by Soluk and others in 1998. The larval habitat in both Illinois and Wisconsin has dried up in the summer months during different years, and rainfall amounts in both Will County, Illinois and Door County, Wisconsin, show similar drought frequencies, noted Soluk and others in 1998, noting that Hine’s emerald dragonfly larvae may be adapted to survive drought conditions.  

Hine’s emerald dragonfly goes through three adult phases: pre-reproductive, reproductive and post-reproductive as noted by Cashatt and others in 1991. Pre-reproductive adults may fly 1 to 3 kilometers (0.6 to 1.9 miles) from their emergence sites and take short feeding flights of one to three minutes. Reproductive adults establish breeding sites and territories using these areas to mate and oviposit, or lay eggs. Males start patrolling territories approximately seven to 10 days after emergence. Foraging flights for reproductive adults may be 1 to 2 kilometers (0.6 to 1.2 miles) from breeding sites and can last 15 to 30 minutes. Post-reproductive adults behave similarly to pre-reproductive adults.

In 1994, Vogt and Cashatt observed that adult Hine’s emerald dragonflies capture aerial prey in flight and have been observed foraging on small dipterans, which include gnats and other two-winged flies. Typically flight courses are irregular and occur over herbaceous habitat, often near clusters of shrubs or the forest edge as Cashatt, Vogt and others have documented. These insects frequently fly over open fields at a height of 1 to 3 meters (3 to 10 feet). Adults feed any time during the day but are most active during the morning, as documented by Mierzwa and others. Researchers documented that Hine's emerald dragonflies are both crepuscular, or appearing active during twilight, and diurnal, active during the day, and feed in swarms in both Illinois and Wisconsin. Hine’s emerald dragonflies forage over meadows, successional fields, narrow roads and along Lake Michigan, as documented by Vogt and Cashatt in 1994.

In contrast to feeding flights, male territorial patrols are concentrated near aquatic habitats. Territories typically encompass a range of 2 to 4 meters (6 to 13 feet) in length, with flight heights ranging between 0.5 to 2.0 meters (2 to 6 feet), as documented by Cashatt and Vogt in 1990 and later in 1994. Vogt and Cashatt also described territorial patrols in the following text: 

“Males darted rapidly throughout their territories. They frequently hovered and often pivoted while hovering. Males usually conducted territorial patrols within small clearings of cattails, just above lower emergent vegetation (Sagittaria sp.), or just above the cattails. Also, males often assumed territorial patrols over a streamlet and hovered within 0.3 meters (1 foot) of the surface. Occasionally, they perched near the top of cattail floral spikes. Territories were defended from intrusion by conspecific and nonconspecific Anisoptera [dragonflies].”   

Hine’s emerald dragonflies patrol above both more permanent waters, known as streamlets, and temporary waters that are inundated forest edges, observed Soluk and others in 1998.

Dispersal, between and within sites, in Illinois was documented during a 1995 mark-resighting study by Mierzwa and others and later by Cashatt and Vogt in 1996. From 180 marked Hine’s emerald dragonflies, four out of a total of 48 resighted individuals were observed on a different site from which they were captured. Dispersal occurred from River South to Lockport Prairie Nature Preserve twice, Lockport Prairie Nature Preserve to River South and Middle Parcel to Lockport Prairie Nature Preserve. The distances these four individuals traveled ranged from 3.3 kilometers (2 miles) to at least 5.4 kilometers (3.4 miles). Within River South Parcel, one male was documented traveling about 800 meters (875 yards) in approximately two and a half hours. Cashatt and Vogt noted in 1996 that the Des Plaines River, and its riparian riparian
Definition of riparian habitat or riparian areas.

Learn more about riparian zone, may be an important dispersal corridor. Although dispersal between sites was not documented in Wisconsin, Kirk and Vogt noted in 1995 that the extensive wetland system between the known sites in Door County may facilitate the dispersal of Hine’s emerald dragonfly.

Vogt and Cashatt observed copulating pairs from early June to late August in Illinois, and from early July to late July in Wisconsin.  Males have also been observed intercepting females within their territory, flying off in tandem with a female and copulating while perched in shrubs, as documented by Vogt and Cashatt in 1994. Soluk and others observed females flying over to males, which resulted in copulation. These females were flying in a regular pattern approximately 0.5 meters (1.6 feet) above the cattails. Occasionally, the females would chase nearby dragonflies, and on three occasions, these confrontations led to copulation. E. Cashatt, with the Illinois State Museum, noted that this female behavior is considered atypical for the genus Somatochlora and for other dragonfly species.

Hine’s emerald dragonfly females oviposit, or lay eggs, by repeatedly dipping their abdomens up to 200 times in shallow water. Observations of oviposition in Illinois range from late June to late August, as Vogt and Cashatt documented in 1997, and from early to late July in Wisconsin. Females have been observed with muck or mud on their abdomens, suggesting these females had oviposited in soft muck and or shallow water. Females with muck on abdominal segments seven to 10 have been observed as early as the 6th of June. Females oviposit in cattail seepage marshes, seepage sedge meadows, sedge hummocks near a marshy stream edge, near the edge of a swale, in muck in sluggish water at the margin of a spring run, in small puddles, in streamlets, and in small marl or muck-bottomed pools, as Vogt, Cashatt and others documented throughout their various research projects in the 1990s. Numerous females have been observed ovipositing between hummocks in shallow water with sheet flow in seepage sedge meadows, as Vogt and Cashatt noted in 1997 and again in 1999. In cattail seepage marshes, females have been observed flying slowly into dense cattail stands. Occasionally, they fly just above cattails and then drop down into small clearings within the seepage marsh. Females will also fly slowly over small, shallow channels approximately 0.2 meters (8 inches) above the water’s surface within seepage marshes. Vogt and Cashatt noted in 1994 that these flights may be pre-ovipositional. All observations of oviposition by Soluk and others in 1998 occurred in more permanent waters, like streamlet and cattail or meadow borders.

E.M. Walker and others noted that other species of Somatochlora that occur in the same range and may be confused with Hine’s emerald dragonfly including: S. linearis, S. tenebrosa, S. ensigera, S. elongata, and S. williamsoni. However, distinctive shapes of terminal appendages and ovipositors separate adults of this species from all other.

Hine’s emerald dragonfly lives in wetlands that are dominated by graminoid, or grass-like plants, and fed primarily by water from a mineral source or fens as F. Swink and G. Wilhelm documented in 1994. Three important characteristics common to wetlands that are inhabited by Hine’s emerald dragonfly appear to be groundwater fed, with shallow water that is slowly flowing through vegetation, dolomitic bedrock or calcareous limestone, and co-inhabited by crayfish, like devil crayfish (Lacunicambarus diogenes). The flowing water can range from barely detectable sheet flow to deeper, small well-defined streamlet channels. Parts of the streamlet channels are usually covered by vegetation such as cattails or sedges. These slow-moving aquatic systems provide appropriate habitat for larval development. Soil types of these aquatic systems can range from organic muck to mineral soils like marl. Two other important components of these wetland complexes are open, vegetated areas and nearby or adjacent forest edge and uplands. Areas of open vegetation serve as places to forage. Forest edge, trees or shrubs, near or adjacent, to fens provide areas which may concentrate prey and provide protected areas for Hine’s emerald dragonfly to perch and roost.

We are researching and understanding all of the Hine's emerald dragonfly's prey items which likely change in both size and species as the Hine's emerald dragonfly matures. Adults are known to prey on small dipterans, like gnats and other two-winged flies.  Analyses of fecal pellets from Hine’s emerald dragonfly larvae indicate this species feeds on oligochaetes and larval mayflies and  caddisflies, which are common in its habitat as D.A. Soluk and others documented in 1998. Direct observation of larvae in containers indicate that Hine’s emerald dragonfly will attack and consume mayflies, isopods and smaller larvae of a related species, Somatochlora williamsoni as also noted by D.A. Soluk's work for with the Illinois Natural History Survey. G. Pritchard and others documented that dragonfly larvae commonly feed on smaller insect larvae, including mosquito and dragonfly larvae, worms, small fish and snails.