In last week's episode, we visited two masters of disguise in the meadow, the jagged ambush bug and the camouflaged looper, as they captured unsuspecting prey and hid from lethal predators, respectively. This week we meet two clever species of moths with a different strategy for survival. One of the most widely used tactics in the insect world is to advertise one's nasty flavor or potent defense with bright coloration or conspicuous behavior. Many strikingly colored moths and butterflies such as the beautiful milkweed tiger moth and monarch butterfly we met in previous episodes employ this mode of defense called aposematism.
One of the most dependable herbaceous perennials, hardy ageratum, Eupatorium coelestinum, is a masterful attractor of pollinators. Over the past month, it has been busy providing nectar and pollen to a dazzling array of bees, beetle, and butterflies for several weeks. This week two showy moths made regular appearances in the Eupatorium patch.
The ermine moth, Atteva aurea, dresses in a spectacular robe of white, orange, and black. Unlike many nocturnal moths, Atteva aurea is a daytime visitor to Eupatorium, where it feeds on nectar. The female lays eggs in clusters on the leaves of the invasive Tree of Heaven, Ailanthus altissima. Caterpillars known as ailanthus webworms hatch from the eggs and build a communal web from which they forage on the leaves of Ailanthus. Small trees may be almost completely enshrouded by the nests of the webworm and they may sustain almost complete defoliation. So efficient are the caterpillars at munching leaves of Ailanthus that some consider them a biological control agent for the invasive Tree of Heaven.
Another bold visitor to the ageratum was the beautiful yellow-collared scape moth. This member of the tiger moth clan is a common visitor to gardens and meadows in late summer and autumn. Dressed in classic black with a bright orange or yellow collar, this moth may also be seen feeding during the day, as well as after sunset. The yellow-collared scape moth lays her eggs on grasses and sedges. The rarely seen scape moth caterpillars feed at night.
Bug of the Week thanks Jack for providing the inspiration for this week’s episode. “The Insects: An outline of entomology” by P.J. Gullan and P.S. Cranston and “Assessing potential biological control of the invasive plant, tree-of-heaven, Ailanthus altissima” by J. Ding, Y. Wu , H. Zheung, W. Fu, R. Reardon, and M. Liu were used in preparation of this story.