Saturday, October 11, 2014

Western Forktail

On 17 July 2014, Erika and I found another new odonate for us along the Madison River, Gallatin Co., Montana. The green thorax stripes and the blue-notched tip of the abdomen are indicative of the Western Forktail. Separating Eastern from Western Forktails can be nearly impossible in the field, but, fortunately, only the Western is found in western Montana—the Eastern venturing only to the Dakotas and eastern Montana, Wyoming, Colorado and New Mexico.

Males like this one are usually vastly outnumbered by their females. Similar to the Eastern Forktail, females need copulate only once, and then use one male’s sperm to fertilize their eggs. By fluttering their wings and curling their abdomens, the females, in fact, often repel males’ advances (Paulson 2009).

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