Happy October! With the dramatic drop in nighttime temps and frosts rolling in, we are officially in the thick of fall and nearing the close of the buggin’ season. Sunny days still offer light insect activity, but most species will be hunkering down or dying off in the next few weeks. We will likely eke out a few more weeks, but don’t wait to get out there! Snow will be here before we know it.

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: West Coast Lady (Vanessa annabella)

Glenn Marangelo, September 28th, 2024. Missoula, MT.


Alflafa Looper

Autographa californica

Unlike most moths, Alfalfa Loopers are active both day and night. You may see them visiting flowers during the day or fluttering to lights at night. They range throughout the west, from as far north as Alaska and south to northern Mexico. Adults can be found in a variety of habitats from May to October in the north, suggesting multiple generations in one season. Caterpillars feed on a wide variety of plants. They are particularly fond of alfalfa and peas.

Connie Geiger, September 25th, 2024. Helena, MT.

Asian Lady Beetle

Harmonia axyridis

This common species was introduced to the US in the early 1900s to help control aphids. Unfortunately, they are an aggressive species that has since established and impacted our native ladybugs. Their color can range from light orange to deep red, with the boldness and number of spots varying between individuals. The top of the thorax is often pale, with an M-shaped dark spot, but it can be black with white outer edges in darker forms. Due to the variance in elytra patterning, using the thoracic markings to identify this species is recommended.

John Krempel, September 21st, 2024. Miller Creek, Missoula, MT.

Locust Borer

Megacyllene robiniae

Originally hailing from the northeast United States, the locust borer has made its way west as its host plant, black locust (Robinia pseudoacacia), has been cultivated and used for landscaping purposes across North America. Both the insect and plant are now considered invasive in our area despite originating on the North American continent. The larvae feed on (and are considered serious pests of) black locust, while the adults take nectar, preferentially from goldenrod (where these two were found).

Glenn Marangelo, September 28th, 2024. Missoula, MT.

European Mantis

Mantis religiosa

European Mantises, as their name suggests, are not native. Each year, gardeners purchase egg cases (called oothecae) with the idea that the emerging mantis nymphs will eat other insects that are bad for their flowers or vegetables. It’s debatable whether they have a beneficial impact since the growing mantises inevitably eat insects that pollinate our plants, too. In addition to the annual introduction by some gardeners, in late summer/early fall, the females will lay two to three oothecae, and anecdotal evidence suggests the egg cases are surviving our increasingly mild winters.

Alyssa Johnson, September 19th, 2024. Bonner, MT.

Twice-stabbed Lady Beetle

Chilocorus stigma

This unique lady beetle species has a descriptive albeit gruesome common name. Being all black, except for two red dots in the center of each wing cover (elytra), they certainly look like they’ve been “twice-stabbed.” The morbid appearance and name feel especially appropriate as we enter spooky season, when the adults are most active. While many ladybugs feed on aphids, the twice-stabbed focuses on scale insects and is an effective predator of pine needle scale insects. They are found throughout the United States, except west of the Sierra Nevada.

John Krempel, September 19th, 2024. Miller Creek, Missoula, MT.

Hobo Spider

Eratigena agrestis

Widespread misinformation has created unfounded fears regarding this common spider. Even their nickname, “aggressive house spider,” is misleading. Their name comes not from their behavior but a misinterpretation of their Latin name, Eratigena agrestis. The species name agrestis does not translate to aggressive; it’s Latin for ‘rural’ because, in this spider’s native European range, it inhabits fields. In addition to the entirely inappropriate common name, hobo spiders’ reputation is the result of a single study conducted in the 80s that found a severe effect of their venom on rabbits – not humans. Once thought to have a bite that can kill the surrounding tissue (necrotizing), considerable research has proven this wrong.

Sal Culotta, September 24th, 2024. Missoula, MT.

Underwing Moth

Catocala sp.

There are about 250 species of underwing moths (genus Catolcala), and many of them feature intriguing common names, like the Once-married, the Sweetheart, the Briseis (named for the Illiad character), Hermia’s (from A Midsummer Night’s Dream), and the Mother. The group as a whole is named for the flashy, colorful hindwings, which greatly contrast with their cryptic forewings. At rest, the hindwings are completely hidden, but if the moth is disturbed, it erupts with a flash of color, potentially scaring any nosy predators seeking an easy meal.

Judy and Bob Hoy, September 25th, 2024. Willoughby Creek, Stevensville, MT.

Western Hornet Fly

Spilomyia citima

Many hoverflies exhibit cryptic black-and-yellow patterning, doing their very best to mimic a wasp in an attempt to be left alone. But the hornet flies (an ironic name, considering the only true hornet found in the US is the European hornet, and is only found on the East Coast) really take the cake when it comes to mimicry. Flies can usually be differentiated from bees and wasps by several features: their short, stubby antennae, two airplane-shaped wings, and characteristic “fly eyes.” However, hornet flies also feature a striped pattern on their eyes, visually disrupting the “fly eyes” look most flies are so well known for.

Glenn Marangelo, September 28th, 2024. Missoula, MT.

Large Yellow Underwing

Noctua pronuba

Large Yellow Underwings are named for their bright orangish-yellow hindwings decked with a narrow, black outer band and orangish-yellow fringe. The hindwings are covered at rest, but revealed if the moth is disturbed or in flight. These moths are native to Eurasia but were accidentally introduced to Nova Scotia in the late 1970s. Strong fliers, they dispersed, and have since spread north to the Arctic Ocean, west to the Pacific, and south to the Gulf of Mexico. They are now one of the most common moth species in many habitats.

Alyssa Johnson, September 22nd, 2024. Bonner, MT.

Four-humped Stink Bug

Brochymena quadripustulata

Does this stink bug look like a familiar house guest? They’re not looking to eat anything, just a warm place to hang out until spring. That said, stink bugs are generally not very welcome house guests for one obvious reason: they stink. As a defensive measure, stink bugs emit foul smells to ward off predators – or occasionally an unwitting human trying to remove it from their home. As true bugs, they have piercing and sucking mouthparts that they use to pierce and consume plant tissues, and many are considered pest species.

John Krempel, September 21st, 2024. Miller Creek, Missoula, MT.