Wisconsin Odonata Survey


Enallagma clausum  Morse, 1895
Alkali Bluet

Coenagrionidae, Pond Damsel Family
"Most Wanted" Species

The bluets form a group of about 17 similar species in Wisconsin in which the males usually share the characteristics of having blue and black stripes on the thorax, and blue and black markings on the abdomen. In-hand examinations are usually needed to identify them, although they can be grouped into subcategories based on the amount of black showing on the abdomen. Males are easily identified, under magnification, by the shape of their terminal appendages. Females are generally duller than males, and they are more difficult to identify, which is accomplished by subtle differences in the shape of the mesostigmal plates on the top of the thorax. Generally, males are bright blue while the females are green or yellow-green or blue. There are some species that are yellow-orange, a mix of various colors, or black with some blue.


Global: G5     Wisconsin: S1?    

Distinguishing Characteristics:

The male of this species is an intermediate-type bluet because of roughly equal amounts of the blue and black on the abdomen. Similar to the boreal bluet and northern bluet, the length of an alkali bluet varies from 1.1 to 1.5 inches. The male's thorax is blue with a black mid-dorsal stripe and black shoulder stripes. The female is similar but with pale colors tan or pale blue and an abdominal pattern with more black.

Description of Habitat/Range:

Found throughout northern and western United States and southern Canada, the preferred habitats for the larvae are not well known. It seems to prefer saline and alkaline waters, although it also has been found at freshwater lakes with little vegetation. This species was documented in Wisconsin for the first time in 2004, in Douglas and Bayfield counties, near the Lake Superior shore.

Flight Season:

Throughout its range, the flight season starts in mid-May to late August.

Shading illustrates monthly percentages of the total flight season records for the species. Each flight season record is a unique date/location/observer combination where one or more adult or an exuvia was recorded (excludes nymphs). The actual number of flight season records for each month is shown in parentheses.

Flight seasons begin earlier in the southern part of the state, often by a week or more. Also, flight charts may not be accurate for rare species because of few data available.
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Photo of Male and female alkali bluet
Male and female alkali bluet. © Dennis Paulson

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