Wisconsin Odonata Survey

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Enallagma vernale  Gloyd, 1943
Vernal 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.

Status-Global/State:

Global: G4     Wisconsin: S1Q    

Distinguishing Characteristics:

The male of this species is a blue-type bluet because of its predominantly blue abdomen. This species is very similar to, and difficult even for specialists to separate from, the northern bluet. However, the most recent research suggests specific status for both, and that is how we treat them here. Some odonatists consider these forms to be subspecies. There are some evidence of intergrading between the vernal bluet and northern bluet in some parts of United States.

Description of Habitat/Range:

The range of this species seems to be northeastern United States and southeast Canada. It seems to be found at lakes, rivers, and ponds. It may be very rare in Wisconsin, but because it has often been confused with the northern bluet, its actual status is unknown.

Flight Season:

In Wisconsin a few adults have been documented from mid-May to late June.


Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
40%
(4)
60%
(6)
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 in wheel
Male and female in wheel. © Dennis Paulson

Male and female in wheel



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