Montana Field Guide

A medium-sized damselfly with a distinctive red-spot at the base of otherwise clear to smoky-colored wings and a red thorax (as males) with an iridescent gold-green abdomen. American Rubyspots prefer habitats of open, clear streams and rivers with moderate to rapid flow and emergent and shoreline vegetation. Abundant populations exist on the lower Marias, Missouri and Musselshell Rivers, as well as the lower Bighorn, Tongue and Power Rivers of the Yellowstone Basin.

American Rubyspots prefer habitats of open, clear streams and rivers with moderate to rapid flow and emergent and shoreline vegetation. Wooded reaches with sunny patches are also selected by this species (Westfall and May 1996, Nikula et al. 2002, 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 distinctcive red spots on the wings of male American Rubyspots continually increases in size throughout the life of an individual. These larger spots apparently leads to more success at holding a territory. However, these same individuals are apparently less successful at hunting (Paulson 2009).

Male American Rubyspots are very territorial and perform display flights toward other males. Females rubyspots are conspicuously present at breeding sites and are often seen with males; unusual for damselflies. No courtship exists with this species, rather males simply grab females and copulation is brief. Interestingly, the females are also territorial at breeding sites when ovipositing on submerged vegetation, often submerging below the waterline. Males guard area and female from other males during oviposition, even though a second copulation is unlikely (Nikula et al. 2002, Paulson 2009).