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Bug of the Week is written by "The Bug Guy," Michael J. Raupp, Professor of Entomology at the University of Maryland.

Stylish Lepidoptera: Ermine Moth, Atteva aurea; Yellow-Collared Scape Moth, Cisseps fulvicollis; Pearl Crescent, Phyciodes tharos; Variegated Fritillary, Euptoieta claudia


 Ermine moths wear a royal robe of orange, black, and white scales.


To celebrate Halloween, Bug of the Week features four stylish Lepidoptera, members of the butterfly and moth clan dressed in orange and black. This episode revolves around a patch of hardy ageratum, Eupatorium coelestinum one of the most dependable herbaceous perennials and a masterful attractor of pollinators. Over the past months, it has been busy providing nectar and pollen to a dazzling array of bees, beetles, and butterflies. Recently, several showy moths and butterflies made regular appearances in my ageratum patch.

Spectacular moths make a splash

The ermine moth, Atteva aurea, dresses in a spectacular robe of white, orange, and black. Unlike many nocturnal moths, Atteva is a daytime visitor to ageratum 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, Cisseps fulvicollis. Last week we visited cousins of the collared scape moth in the episode entitled “Dashing caterpillars predicting weather- Woolly bears, Pyrrharctia isabella, yellow bears, Spilosoma virginica, and leopard moths, Hypercompe scribonia." A member of the tiger moth clan, the yellow-collared scape moth is a common visitor to gardens and meadows in late summer and autumn. After feeding on nutritious nectar and pollen, the yellow-collared scape moth lays her eggs on grasses and sedges. Scape moth caterpillars are rarely seen because, like vampires, they feed at night.


Yellow-collared scape moths seek nectar during daylight hours


Gorgeous butterflies also drop by to feed

Beautiful moths were not the only visitors to the ageratum. For the past several weeks, two spectacular species of butterflies frequented the purple blossoms. The first was the delightful pearl crescent, Phyciodes tharos. These small, active members of the brush footed butterfly clan may have as many as three generations in Maryland and up to six generations in Georgia and Florida. Adult pearl crescents feed on nectar and pollen of a wide variety of plants including milkweed, dogbane, and black-eyed Susan as well as other members of the aster family. However, when it comes to food for her young, the female pearl crescent favors asters above all, where she deposits up to 700 eggs over the course of her lifetime. In temperate states like Maryland, hardy pearl crescent caterpillars brave the winter in a hibernation-like state called diapause and complete their development in spring when warm weather and succulent leaves return.

Nectar of ageratum is highly attractive to the pearl crescent


Butterfly weed is a favorite nectar source for the variegated fritillary.

The final member of our autumn ensemble is the variegated fritillary, Euptoieta claudia .  These vagabonds are one of the last butterflies active in Maryland at the end of each growing season. Variegated fritillaries are regular visitors to open sunny areas such as fields, pastures, and along the edges of roads.  After feeding on pollen and nectar from milkweeds, dogbane, and red clover, female fritillaries lay eggs on the leaves of plants such as maypops, may apple, purslane, stonecrop, and moonseed. My landscape isn’t rich in these species, but on a sandy hillside beneath some trees, violets grow in spades. Here I find the larvae of the variegated fritillary. In addition to wild violets, I recently learned that the pansies growing in my flower beds are also on the menu for fritillary caterpillars (see A welcomed vagabond - Variegated fritillary, Euptoieta claudia ).

I lament the disappearance of the pearl crescents, scape moths, and ermine moths for the year and with winter just around the corner the last of the variegated fritillaries will soon be gone as well. They are nomads and can only survive winter across the southern tier of states where warm temperatures and food-plants enable larvae and adults to survive year round. The arrival of Halloween and the first hard frost invariably prompt a visit to my calendar to begin planning a trip somewhere warm where butterflies and moths abound.  


The wonderful books “Caterpillars of Eastern North America” by David Wagner and “Butterflies East of the Great Plains” by Paul Opler and George Krizek were used as references for this episode.  Have a happy and safe Halloween!