We’ve officially reached the last few days of summer, though it certainly feels like fall has been settling in for a couple of weeks now. Many of our fall arrivals are making their debut, like the enchanting woolly aphids, whose appearance signals – to us, at least – that the buggin’ season is approaching a close.
Submit your bug pictures to bugid@missoulabutterflyhouse.org (and remember to include your name, the date, and the location where you took the photo)!
Header Photo: Shield-backed Bug (Homaemus aeneifrons).
Chelsea Klocke, September 15th, 2024. O’Brien Creek, Missoula, MT.
Many-spotted Tiger Moth
Hypercompe permaculata
This moth takes the cake for most fashionable insect this week; there are several species of white tiger moth with black spots, but the many-spotted looks like it should be hosting America’s Next Top Model (or playing the villain in a certain Disney franchise). They range throughout the western United States (except the Pacific Northwest) and southwestern Canada, with adults taking wing from June to August.
Glenn Marangelo, September 18th, 2024. Pray, MT.
Maple Spanworm Moth
Ennomos magnaria
Autumn leaf or living insect? These delicate looking moths are typically found flying from mid to late summer into early fall when their dried, leaf-like appearance is most helpful for camouflage. They inhabit mixed and deciduous forests from coast to coast in southern Canada and the northern U.S. (also found south along the east and west coast, being absent in parts of the central and southern states). The larvae are no camouflage slouches themselves, expertly mimicking a twig.
JH, September 6th, 2024. Spokane Creek, Helena, MT.
Fierce Orbweaver
Araneus saevus
This orb weaver is fierce in name only (and maybe appearance, if you’re a bug). Like all North American orb weavers, this species is harmless to humans. This species is found throughout north and central North America, though is largely absent from the Great Plains. Usually, they’re found on the sides of trees, but this individual was hanging out at the lodge at snowbowl. The white dash on the front of the abdomen is diagnostic for this species.
Alison Cobb, September 14th, 2024. Snowbowl, Missoula, MT.
Prominent moth
Datana californica
We believe this caterpillar belongs to the Datana genus, of which there are only a few species in our area. As an adult, species in this genus look like a dead, rolled-up leaf; an excellent form of camouflage to protect them from becoming lunch. This species is found west of the Rockies, from southern BC to northern California. A similar species, D. ministra, is primarily found east of the Rockies. The genus name, Datana, is an anagram of two other moth genera, Natada and Nadata; all three were described by Francis Walker in 1855.
Klara Briknarova, September 17th, 2024. Missoula, MT.
Large Rove Beetle
Tribe Staphylinini
There are over 4,100 species in this large family of beetles. Most of them are predators, many of which are beneficial predators of pest insect species. They can range in length from about one-eighth of an inch to nearly an inch. Adult rove beetles can often be found on animal carcasses where they eat the other insects feeding on the carcass. Although they have wings and can fly, they usually prefer to run along the ground.
Klara Briknarova, September 15th, 2024. Maclay Flat, Missoula, MT.
Golden Dung Fly
Scathophaga stercoraria
Luckily for our identification efforts, this is a male Golden Dung Fly. They are a bit easier to identify than the grayer females since they are bright yellow or golden. These small flies have multiple generations a year and can be found from spring through the fall. The adults lay their eggs on dung, which the emerging larvae feed upon. After pupating and becoming an adult, their diet switches to preying on other fly species and insects.
Glenn Marangelo, September 18th, 2024. Charlo, MT.
Woolly Aphid
Family Eriosomatinae
On sunny fall afternoons, it sometimes looks like it is snowing. But it’s not snow; it’s the annual fall swarming of woolly aphids. These insects are tiny. If it were not for their woolly appearance, you might not notice them at all. Their appearance comes from white, cottony wax filaments they produce from special glands that make them appear like small, flying cotton balls. This wax helps prevent them from drying out, protects them from predators, and makes it easier for them to slip through and around plant hairs. There are many different species of woolly aphid, each specific to a host tree. They inhabit alder and maple, ash, and birch trees.
Wendy Brooke, September 16th, 2024. Polson, MT.
Dart moth
Agrotis sp.
Cutworm and dart moths from the subfamily Noctuinae are notoriously difficult to differentiate from each other. We suspect this individual belongs to the genus Agrotis; there are 23 species in this genus North of Mexico. Many moths in the family Noctuinae can only be identified via dissection or DNA analysis. There is little information on this group of moths, with an unknown number of species across the globe. Cutworm and dart moths are diverse, with well over 400 species in North America alone.
JH, September 6th, 2024. Spokane Creek, Helena, MT.
Scudder’s Bush Katydid
Scudderia sp.
Katydids in this genus range throughout the United States and into southern Canada. The adults feed on broad-leaved woody deciduous plants while the nymphs can be found perusing a variety of herbaceous flowers. Adults may be found from early summer into autumn, often dying off around the first hard freeze; meanwhile, their eggs will survive the winter, falling to the ground in the autumn with the leaves they are attached to.
Karla Roeseler, September 13th, 2024. Rattlesnake Wilderness Recreation Area, Missoula, MT.
Leafy Spurge Hawkmoth
Hyles euphorbiae
These large hawkmoths (sphinx moths) are a non-native species that were released in the fight against leafy spurge (the food source for their beautiful caterpillars, shown here). As the first biological agent to combat leafy spurge, these moths have inhabited the United States since 1965. The caterpillars are striking, with colors ranging from vivid green and yellow to dark red, orange and grey, depending on the caterpillar’s age. As adult moths, their wingspan can reach close to 10 cm, and like many day-flying moths, are often mistaken for hummingbirds.
Klara Briknarova, September 14th, 2024. Mt. Sentinel, Missoula, MT.
