Missouri Master Naturalists- Springfield Plateau Chapter

Friday, July 13, 2012

Oakworm Moth


A. senatoria female
I have been hanging up a bed sheet on the deck and turning on a light to attract moths.  This is usually while I am at the creek overnight by myself.  Good news for guests- it is an old sheet, not off the guest beds.

As the deck is located on a small bluff over Bull Creek valley with woods and open fields, the variety of moths we attract is quite diverse.  Many of the small tan moths are beyond my abilities to identify, while others are distinctive and even beautiful.

Gregarious Oakworm Moth Cats- Wikimedia
I found this beauty one morning last week.  Using a combination of resources listed below I identified it as Orange-tipped oakworm moth, Anisota senatoriaThey are members of the Saturniidae family which includes the large silk moths such as the Luna.  This family doesn't have a functioning digestive tract and therefore do not eat as adults.  They emerge this time of year, seeking out mates, breeding and laying their eggs on oaks.

A. senatoria male- Barnhart
This is a female with a georgous yellow-orange color.  The A. senatoria moth exhibits sexual dimorphism, a different appearance between the male and the  female.  BAMONA describes it like this.
"Females can be twice as large as males. Upperside of female is yellow-orange to yellow-brown; forewing has a white cell spot and varying amounts of scattered black specks. Upperside of male is reddish orange to brownish orange; forewing is narrow with a small white cell spot."

Their larvae are gregarious, clustering on branches while chowing down like a college football training table.  They may consume large numbers of leaves on selected trees.  This generally doesn't harm the trees as they are eating them during August and September when the trees have already stored up most of their energy for the year.

Stealing from Chris Barnhart's pictures as usual I found these great pictures of the other three stages of A. senatoria's life cycle.  Like many smaller caterpillars, it is really quite beautiful under magnification, a welcome sight unless you happen to be an oak tree.







*Bugguide, BAMONA and Moth Photographers Group