Saturniidae At Southern 8ths

When it comes to nature, I’m easily excitable.  Of this, I am well aware.  On more than one occasion, I’ve been leading a nature walk and I see something that gets me so excited, the people around me either get just as excited or wonder what is wrong with me.  Nature is full of wonder and surprises and I’m always seeing things that remind me of those wonders and surprise.  My last day in the field during my most recent visit to Southern 8ths Farm began with with another excitable moment for me.

Walking down from above the barn, I spotted a bright orange spot on the concrete in front of the door to the garage and equipment shed next to the barn.  I hurried down the stairs and found the orange spot to be one of the Giant Silkworm Moths.  It was a Regal Moth (Citheronia regalis), sometimes called the Royal Walnut Moth, due to the caterpillars love of the leaves of Black Walnut (Juglans nigra) and Hickory (Carya sp.) trees.  The caterpillar of this species of moth is often referred to as “Hickory Horned Devil” because of their menacing appearance and their affinity of hickory leaves.  While they grow to an enormous size (almost 6 inches is not out of the question), do have horns and may resemble some devilish caterpillar, this largest caterpillar in North America is completely harmless!   Giant Silkworm Moths are members of the Saturniidae family of Lepidoptera and are often rather large moths with “hairy” bodies and eyespots on their wings.

In case you’ve never been on one of my nature walks, Lepidoptera is an order of insects that includes moths and butterflies.  Both moths and butterflies have scales, which are very much modified hair-like structures, covering their bodies and their wings.  Lepidoptera literally means “scaled-wing”.  As for Saturniidae, Saturn was the Roman god of many things (liberation, agriculture, wealth and plenty).  One of his dominions was that of generation and periodic renewal.  A caterpillar changing into a bright moth certainly evokes images of renewal and generation.

DSC_1437 Looking at the Regal Moth pictured, the spots on the wing are clear and the “hairy body” is quite obvious.  Regal Moths are in the subfamily of Ceratocampinae, of which there are over 30 members.  Measuring nearly 5 inches wide, this Regal Moth was right in the middle of the expected wingspan of 4-6 inches.  Pretty impressive size for a moth!  And, to answer the question I’m sure you’re already asking; yes, Regal Moths are related to the large green Luna Moths (Actias luna) we are all familiar with.  They are; however, not the same silk moths as those used in the commercial silk trade.  Those Asiatic silkworm moths belong to the family Bombycid.  One other unique fat is that as large as the caterpillar of the Regal Moth grows, the moth is far from the same size as the caterpillar and is not the largest moth in North America.  The largest moth in North America is the Cecropia Moth (Hyalophora cecropia).

DSC_1454 A head-on look at the Regal Moth.  I’ve often described the face of this moth as a “bright orange goblin face” to Master Naturalist students.

Just a few feet away from where I discovered the Regal Moth, I found another member of the Saturniidae family.  A Promethea Moth (Callosamia promethea) was fluttering in the pine straw next to the same building on my June trip to Southern 8ths.  A cousin of the Regal Moth, Promethea Moths belong to the subfamily Saturniinae, making them true Saturns.  A little smaller than its cousin, the Promethea Moth has a wingspan of almost 4 inches.

FullSizeRender-14 As the name implies, this female Promethea Moth owes its name to Prometheus, the Titan who, in Greek mythology, stole fire from Zeus and gave it to mortal man.  While the female (pictured) has a lot of light brown on its wings, the male is mostly the deep chocolate and black colors you see in the middle of her wings.  This “charred” appearance makes the moth look as though it has been burned by the fire of Prometheus.  Let’s hope, for the sake of this moth, Zeus doesn’t chain it to a rock and curse it to have it’s liver eaten by an eagle each day for an eternity!

Promethea Moth caterpillars are very much generalists when it comes to larval food sources.  They may eat the leaves of a variety of trees, such as Tulip Poplar (Liriodendron tulipifera), Sassafras (Sassafras albidum), White Ash (Fraxinus americana) and Spicebush (Lindera benzoin).

Sometimes, little behaviors are the most intriguing.  Caterpillars of the Promethea Moth will regularly prune partially eaten leaves on the trees in which they dine.  They do this by snipping the petiole of the leaf where it emerges from the tree.  The reason?  Oh, that’s the real genius of nature!  They do this to lower the likelihood of a potential predator keying in on leaves being consumed by caterpillars!  If that doesn’t get you a little excited about the wonders of nature, you’re just going to have to visit Southern 8ths Farm and go on a nature walk with me.

Now, the question begs to be asked, “Why would I find two Giant Silkworm Moths in the same area on different occasions?”  There are many nightlights outside the buildings of Southern 8ths and they shine down on large white buildings all night long.  As we remember from middle school science, moths are attracted to light, as they use the moon and stars to navigate by.  The nightlights at Southern 8ths draw them in, where I occasionally find them the next morning.

Now, I’m looking to make “Josh’s Jottings” as interactive as possible.  So, any questions or comments you may have are welcome!  As I’ve often said, nature should be shared and enjoyed by all.  So, get out there and explore.  If you see something and you want to know more about, send in those questions.

A naturalist is one who marvels at nature and studies it.  You, too, are a naturalist.  Let’s marvel and study it together!

-Josh