Gardens of the Cross Timbers: Moth night

Becky Emerson Carlberg
Contributing writer
Charlotte and her egg sack

The winds were unkind to the Orb Weaver. For weeks she had maintained her magnificent web stretching over a foot in diameter between the Spirea and the persimmon tree. Each morning she repaired any damage incurred the night before. Then, one night ferocious breezes swept leaves from trees and sent pine needle daggers through the air. Her web could not withstand the onslaught and came down. Bits of silk embedded with pine needles dangled from the persimmon. I couldn’t find the spider.

Two days later, she reappeared by the front door frame at the level of the door handle. The large spider had woven a very tiny web around the sticks propped up in the corner, just inches from the door. The immobile Orb Weaver seemed nonplus whenever we entered or left the house. On the morning of the fifth day, she had created a large egg sack and was busy putting on the finishing touches. I’m not sure this is a great place for her future family, but she thought so. The Orb Weaver’s egg sack looks like a miniature upside-down dark tan hot air balloon suspended in mid-flight. Orb Weaver egg sacks can hold hundreds of eggs, which will hatch in a few weeks. The baby spiderlings stay inside the egg sack until spring.

The next day mom had walked around the door, and parked herself on the door frame directly opposite the egg sack. She was a withered version of her former vibrant round self. Her work was done. Two days later she retraced her steps, and spun a small web two feet above the egg sack. The spider caught and dined on a bug, so she’s back in business.

From a garden point of view, the Orb Weaver is a great spider to have. The arachnid loves to eat flies, moths, mosquitoes, beetles and other flying insects. On the other hand, bats, frogs, lizards, cats, bluebirds, wrens, and crows dine on spiders. There’s one insect the Orb needs to avoid. The dirt dauber wasp will land on the Orb Weaver’s web and act like a trapped bug. The Orb rushes forward in anticipation of a great meal. The wasp quickly stings and paralyzes the spider, picks it up similar to the way a claw machine grabs a stuffed animal, and carries the helpless thing to its mud nest. The wasp lays an egg in the spider’s abdomen and seals the nest from the outside with mud. The doomed spider will be eaten alive by a little waspling at a later date. Wrens on my porch are excellent excavators of dirt dauber nests. There’s some justice in the world.

Shawnee lies under the Central Flyway bird migration route. Numerous ponds and diverse habitats provide support for migrating birds as they go south for the winter. Yellow and black-billed cuckoos, Chuck-will’s widow and its cousin the Whip-poor-will, Ruby-throated hummingbirds, Flycatchers (including the Scissor-tailed flycatcher), swallows, warblers, indigo and painted buntings, gray catbirds and orioles are among the 20% of the total bird population migrating or gone by sometime in October.

Trillions of insects migrate. Large Milkweed Bugs, Wandering Glider and Common Green Darner dragonflies fly south as do the Monarch, Buckeye, Zebra Swallowtail, Red Admiral, Question mark, Painted lady and Cloudless Sulphur butterflies. The Cabbage looper, Pink-spotted hawkmoths and Armyworm moths also take wing.

Mike Trammell, Pottawatomie County Ag Educator, had a recent article about Hay Bales and Armyworms. Armyworm caterpillars are grain, hay, leaf and grass eaters, usually kept in check by natural enemies. Three species of armyworm moths fly up from the Gulf Coast, Texas, Mexico or even the Caribbean in the spring. The true armyworm (Pseudaletia unipuncta) feeds spring and early summer. The yellow-striped armyworm (Spodoptera ornithogalli) becomes active in spring and the fall armyworm (Spodoptera frugipedra) turns into a pest late summer and fall. Several generations later, much like the Monarch, the moths return to warmer climes.

People get panicky when their lawn, hay, or heads of sorghum disappear. First inclination is to bring out the insecticides. When lawns are treated with chemicals for armyworms, the homeowner is also killing Monarch larvae and other pollinators. What kills one moth caterpillar kills all moth and butterfly caterpillars.

Good management and diligent scouting are key to control. Natural controls are far better in a complicated armyworm situation. Armyworms like Bermuda grass, zoysia, rye and fescues. Good time to invest in native grasses. Borders of flowering plants help to decrease armyworm invasions. Invite the birds. Birds eat both the moths and caterpillars. In other words, a balanced diverse landscape can diffuse armyworm attacks. Do you have a Bermuda lawn lined with a few corporate shrubs? Armyworm heaven. Don’t worry. The immortal Bermuda might look awful, but the disgusting grass will probably not die and next year resurface. If your fescue dies, plant the patch in wildflower seeds next spring.

Moth Night Shadows

Saturday night was moth night. In Saxon Park outside Norman were set up several sheets and cloth boxes illuminated by Ultraviolet and bright white lights. UV light, a type of short-wave radiation, attracts a wide variety of moths. Nocturnal moths, flies, crickets, spiders, bugs and beetles climbed on or flitted around the screens while college students and interested observers hovered close by with cameras.

Snout Mot

Moths fly straight in moon light, but in artificial light they go in circles. One eye sees the bright light first, causing one wing to beat faster. Round and round the moth goes. Plume moths, Tiger moths, moths with snouts, and small moths with brightly colored intricately patterned wings performed dizzying acrobatics before either landing or leaving the cloth. We were on the lookout for armyworm moths and I could have seen a dozen, but my moth identification skills are not exactly stellar, even using the Peterson Field Guide to Moths. No large Silk moths or Luna moths. They prefer spring and early summer.

For a cool October evening, it was cool to see so many moths!

Becky Emerson Carlberg

Becky Emerson Carlberg, graduate of Oklahoma State (Plant Pathology) is a teacher, artist, writer as well as certified Oklahoma Master Gardener and Master Naturalist. Contact her at Becscience@att.net.