By Christy Solo – ONPA 1st Place Award Winner for Best Local Column
This week’s crawly is a moth of a different color – rather several colors. Meet the omnivorous looper moth (Sabulodes aegrotata), we’ll call them “omni” for short.
The common name is quite the misnomer. Their pretty, bitty pillars do not actually eat meat, but they do have a very broad diet as caterpillars go. We guess the “wide variety of host plants looper” felt too long as a common name and someone landed on “omnivorous.”
As moth pillars go, omni have very impressive diets. They’ve been recorded dining on plant species in 27 different families. CalScapes estimates that they can use at least 137 different plants as host plants.
Amazingly, despite their vast diet, omnis can only be found in Oregon, Washington, California and the very southernmost points of British Columbia. Expansive diet does not equal expansive (or even expanding) range.
Not only is there a wide variety of plants on the menu for omnis, but they themselves come in a huge range of color and pattern options. Our pictured pair of omnis were both visitors to my front porch, and they really exemplify both ends of the “omni color and pattern spectrum.”
L: Melanic form of the omnivorous looper moth (Sabulodes aegrotata). Photos by Christy Solo
Omni color varies from pale mauve or cream or pale yellow to ochraceous, brown or blackish brown. Most omnis are cream or tan with the mauve and brown as the rarer ends of the spectrum.
The brown/black-brown omnis are the melanic form and omnis are the only species in their genus who have this type of coloration.
Our marvelously mauve pictured omni is on the “unicorn” end of the omni color/patten spectrum. Not only is the dusky rose hue the rarest color form, but nearly all omnis have at least some dark patterning.
Patterns run from rows of dots outlining where darker color bands can sometimes be across the top and middle of the wings to full, darker bands of color, to our melanic omni. Some omnis also have a dusting of the ochre color over a lighter base color of cream or tan.
Not only do omnis come in a painter’s pallet of colors, but they are good sized moths and easy to spot with their 1.75-to-2-inch wingspan.
It can be tricky to identify an omni because they are on the wing every month of the year here in Oregon and we have several similar looking moths such as Tetracis cervinaria and Tetracis jubararia moths. Generally those Tetracis moths are on the wing in fall, so omnis are easier to ID at a glance in spring.
Another unique trait of omnis is that due to their broad diet, they fall into both the beneficial and pest categories.
California considers them a minor pest species because one of the many plants on their menu is the avocado – both leaves and fruit. However they aren’t found in large numbers in CA groves. In fact, treatment of them is only recommended if a grower finds 15 or more pillars in one hour of searching. Def not a Defcon 1 pest.
However, here in Oregon they are not considered a pest, moreover one of their favored meals is English ivy which actually does fall into the Defcon 1 category of noxious weeds in our backyards.
In 2010, the Oregon Department of Agriculture placed English Ivy under noxious weed quarantine (OAR 603-52-1200). This ruling “prohibits the propagation, transport, purchase, or sale of H. helix and H. hibernica [in Oregon], regardless of the variety or cultivar.”
One person’s pest is another person’s Noxious Weed Killing Machine. Okay, petite omni pillars won’t actually eradicate English ivy, but they can put a bit of hurt on it and that’s a good thing. Some folks take extra care to encourage and not to disturb or collect omnis on English ivy.
We’ve included a pic of a pillar so you know to just give them a “thank you” and let them be. Photo by Chris Mallory
