Thursday, July 11, 2013

Eastern Forktail

Eastern Forktails are widely distributed and abundant in the North America—yet I always have found them to be perplexing to identify. Field marks for the male above include the greenish sides of the body and eyes, coupled with the two blue bars on the sides of the blue-tipped abdomen. The first and last photos are taken this summer from Carleton College’s Lyman Lakes. The middle photo, taken in June 2011, is from Carleton’s Lower Arboretum.
Females begin life as orangish bodies (above) but become pruiose (bluish-gray), like the damselfly below. Females only mate once, unusual for damselflies (Dubois). Other females look like males (andromorphs) (Paulson). Larvae go through about a dozen stages (instars) and winter in one of their later stages.
It seems like more often than not, when I encounter a damselfly, it proves to be an Eastern Forktail. This species is found across the northern United States and parts of southern Canada. Eastern Forktails are replaced by Western Forktails across much of the West. The two species are difficult to distinguish—as are several other forktail species.

2 comments:

  1. Dr. Tallman, is there any evidence of cross-breeding across different spieces that you know of?

    Corey

    ReplyDelete
    Replies
    1. Occasionally hybridization is suspected between odonates. For example, our Eastern Red Damsels appear to be intermediate between Western Red Damsels and more eastern individuals of Eastern Reds.

      Delete