Montana Field Guide

The River Bluet is the only species of Enallagma that is restricted to streams and rivers. Other bluets are more commonly associated with lakes and ponds (Acorn 2004, Paulson, 2009) They prefer slow streams and small rivers mostly in open country, but having a riparian component. These habitat types are often associated with outflow of warm springs.

River Bluets prefer slow streams and small rivers mostly in open country but having a riparian component. These habitat types are often associated with outflow of warm springs. This species has also been known to occupy irrigation canals with appropriate vegetation and flow (Westfall and May 1996, Acorn 2004, Paulson 2009).

Larvae feed on a wide variety of aquatic insects, such as mosquito larvae, other aquatic fly larvae, mayfly larvae, and freshwater shrimp.
Adult- This damselfly will eat almost any soft-bodied flying insect including mosquitoes, flies, small moths, mayflies, and flying ants or termites.

The River Bluet is the only species of Enallagma that is restricted to streams and rivers. Other bluets are more commonly associated with lakes and ponds (Acorn 2004, Paulson, 2009).

The River Bluet has been known to hybridize with the Tule Bluet (Enallagma carunculatum). Miller and Ivie (1996) described a new species of Enallagma in Montana, naming it the Last Best Place Damselfly (Enallagma optiomolocus). However, this designation is now in question, as other authors (Donnelly 2008, Johnson 2009) have put forth that E. optimolocus is indeed the hybrid of E. anna and E. carunculatum.

Both River Bluet sexes tend to perch on stems or on the ground in vegetation beds associated with breeding sites. Males often perch on stems at edge of vegetation awaiting females. Oviposition is usually completed by tandem pairs, but females also oviposit singly. Oviposition on floating and emergent vegetation with female completely submerging under the waterline for extended periods (Paulson 2009).