Luna Moths Need Black Walnut, Hickory Trees and Dark Skies

Luna Moth (from Wikipedia)

Two decades ago when I moved to our house in Arlington, Virginia, a Luna Moth took up residence for a couple of days among the moon flowers and morning glories climbing up the bean trellis. Since I was new to Virginia as well as the neighborhood, I assumed Luna Moths were a common occurrence that I would be able to enjoy in my new home. That turned out not to be true, and I’ve only seen two, both more than a decade ago.

 

The Luna Moth, Actias luna, is a lime-green swallowtail with a wingspan of four and a half inches, making it one of the largest North American moths.  Its preferred larval host trees in our area are the walnuts and hickories, but it will also use sweet gum and persimmon trees.  Up north, they go for birch, alder and sumac.  The trees are not damaged by the caterpillars.  After eating their fill of leaves and transforming through five instars (life cycle phases or molts), the caterpillars drop to the ground at the base of the tree, wrap themselves in silk and leaf litter, and pupate.

 

Luna Moths face many challenges to survival in the urban sprawl.  They require dark skies to reproduce.  They fly up to the tops of the host trees well after midnight to mate and lay eggs.  There is evidence that the bright lights from streetlights and buildings interfere with the moth’s ability to reproduce. They are also becoming endangered by the measures to control Gypsy Moths.  

While I haven’t read anything about the effect of leaf collection on Lepidoptera, it seems logical to me that our obsession with raking, mowing and blowing our yards clean has had the effect of sweeping away the pupated moths and butterflies as they undergo the miracle of metamorphosis at our feet.   [for more information on supporting wildlife by leaving in place the  leaves, seedheads and leaf stalks that insects, birds and small mammals depend on, see this post by Pat Sutton "A Love of Untidy Gardens and Why!" on the website Native Plants and Wildlife Gardens]

Finally, as our neighborhood’s original native tree cover is aging and disappearing, we are not replacing them with the species that the local fauna require for food, shelter and reproduction. Maybe we can help keep these beauties around by planting native hosts, leaving some leaf litter each fall, especially at the base of walnuts, hickories and sweet gums, and turning off unnecessary lights at night.

 

For more information on native landscaping for wildlife, have a look at the links on the right =>

Update May 27, 2012: We went for a walk this morning at Huntley Meadows Park in Alexandria, Virginia. On the path of the forested area near the edge of the wetlands, I saw a Luna Moth. It was the first one I have seen in almost 20 years.