10 Common Insects You Can Find in Montana (2025)
Thousands of insect species live in Montana!
Trying to list them all would be impossible. So below, you will find the most common and abundant bugs that live in Montana. I did my best to find an array of different types, such as bees, beetles, flies, mantises, ants, etc.
Also, this article ONLY lists INSECTS. Please check out these other ID guides if you are searching for something else:
10 Common Insects in Montana:
#1. Common Green Bottle Fly
- Lucilia sericata
- Adults have metallic blue-green or copper-green bodies.
- They have black hair on their backs, black legs, and antennae. Transparent wings with light brown veins.
- They’re slightly larger than houseflies.
The Common Green Bottle Fly is one of the most common and well-known insects in Montana.
These bugs are not many people’s favorite, but they have some critical jobs in forensic, veterinary, and medical science! Their larvae or maggot stage can help scientists determine the time of death in investigations.
In their natural habitat, Green Bottle Flies are essential aids in decomposition, feeding on carrion and feces.
Surprisingly, they’re also pollinators. Some plants, like the Pawpaw (Asimina triloba), have adapted to attract them with flowers that have the color of drying blood and an odor of rotting meat.
These flies are incredibly prolific. A single female fly may produce 2,000 to 3,000 eggs in her lifetime. They reproduce quickly, too, completing their lifecycle in just 2 to 3 weeks.
#2. European/Western Honey Bee
- Apis mellifera
- They are primarily red or brown with black bands and orange-yellow rings on their abdomens.
- They have hairy thoraxes and slightly hairy abdomens.
The Western Honey Bee is one of the most common insects in Montana.
Unlike most bee species, Western Honey Bees form perennial colonies which survive for years. These colonies comprise about 30,000 to 80,000 bees, most of which are female, including the queen and worker bees.
Defending the hive can cost these bees their lives. When a Western Honeybee stings, usually its barbed stinger becomes lodged in its target. The attached venom sac and musculature are pulled from the bee, resulting in the bee’s death.
Foraging is hard work! A single worker bee flies at about 15 miles per hour and usually visits 50 to 100 flowers in a single trip.
Despite all this effort, the average worker only produces about 1.5 teaspoons of honey in her lifetime.
This honey is tasty for humans but is also essential for the hive. Workers feed honey to the larvae and feed on it themselves during the winter in temperate climates.
#3. Monarch
- Danaus plexippus
- Monarch butterflies have a wingspan of roughly 4 inches (10 cm).
- Their recognizable coloring is a “stained glass” pattern of orange with black veins. White dots line the outside edge of the wings.
- Caterpillars are plump, with black, white, and yellow bands and tentacles on each end of its body.
Monarchs are easily one of the most recognized insects in Montana!
They are famous for their color pattern and migration. Look for Monarchs anywhere there is milkweed, which is the only food the caterpillars eat.
Most people are familiar with the declining population of Monarchs. Planting milkweed and other native flowering plants is the best way to help them.
Interestingly, Monarchs are toxic to most animals and at the very least, taste bad! This poison comes from the caterpillar’s diet, which is almost entirely made up of milkweed. Toxins from the milkweed plant stay in them, producing a bitter taste and poisonous effects.
During migration, usually in mid-September, you may even see groups of hundreds flying south!
#4. Seven-Spotted Ladybug
- Coccinella septempunctata
- They have red bodies with six black spots and one big black mark on the middle of their wings (hence their name).
- The head is black with two white dots.
- They are also known as Seven-spotted Ladybird and C-7.
When you think of ladybugs, you probably picture something similar to the Seven-spotted Ladybug!
Almost everyone loves them because of the MASSIVE amounts of aphids they eat. This makes them very useful in controlling the pest population of aphids in grasslands and farms.
Surprisingly, this insect is NOT native to Montana.
They were introduced here from Europe as a biological control against aphids. Interestingly, while they are thriving in North America, Seven-spotted Ladybugs are declining in their native ranges in Europe.
Check out this video of the Seven-spotted Ladybug, as it is an eating machine!
#5. Asian Lady Beetle
- Harmonia axyridis
Also known as the Multicoloured Asian Ladybug, Harlequin Ladybird, and Japanese Ladybug.
- Adults have domed bodies and are usually about .25 inches (.6 cm) long.
- Their coloration may range from yellowish-orange to red or black with variable black, orange, or red spots and markings.
The Asian Lady Beetle is NOT a true ladybug. It is similar in how it looks but not in how it acts. It is native to eastern Asia and was brought over to help control aphids like other ladybugs.
Once introduced, this species spread quickly through North America. Many people call it the “Halloween Beetle,” as it often invades homes in Montana during October to overwinter. I know we get MANY Asian Lady Beetles coming into our house each year when the weather turns colder!
This species is considered one of the world’s most invasive insects. Their bodily fluids have an unpleasant odor and can stain fabric, so try not to crush this beetle if you find it inside!
The easiest way to identify this beetle is by the black markings on its head that look like the letters “W” or “M.”
Check out this video of how big of a problem the Asian Lady Beetle can be before winter.
#6. Bald-faced Hornet
- Dolichovespula maculata
Also called the Bald-faced Aerial Yellowjacket, Bald-faced Wasp, Bald Hornet, White-faced Hornet, Blackjacket, White-tailed Hornet, Spruce Wasp, and Bull Wasp.
- They have black bodies with ivory markings on their faces, legs, thoraxes, and abdomens.
- Look for three white stripes at the ends of their bodies.
Bald-faced Hornets are named for the ivory markings on their face. Despite the name, these insects aren’t true hornets. They’re actually a type of yellow jacket.
These intimidating bugs don’t have a pleasant reputation in Montana.
They aggressively defend their nests and can sting repeatedly. But while their appearance and nests can be scary, they’re pretty handy to have around (as long as the nest isn’t close to human habitation).
First, the adults feed on nectar and help to pollinate flowers. In addition, they also kill and eat other types of yellowjackets! Sometimes, in early summer, a nest will be so full of yellowjacket remains that it will have a yellowish cast! Unless their nest is somewhere you’ll come into contact with it, it’s best to leave them be.
I’m sure you have spotted one of their nests before. They are large, papery, and football-shaped. The queen builds these nests by chewing wood material and mixing it with her saliva to make a paste.
#7. Brown-belted Bumble Bee
- Bombus griseocollis
- They have short, even hair.
- A primarily yellow thorax with a black patch between the wing bases.
- Their first abdominal segment is entirely yellow, and workers usually have a brown or reddish patch in a crescent shape on the second segment.
Brown-belted Bumble Bees are incredibly adaptable. They feed on various flowers like clovers, echinaceas, goldenrods, milkweeds, and vetches. And they have a wide range of habitats in Montana, including wetlands, agricultural areas, meadows, and even cities!
Brown-belted Bumble Bees live in small colonies of about 50 or fewer individuals. They nest underground or on the surface in organic matter.
These groups may be small, but they are mighty and will aggressively defend their nests from predators and parasites.
Unlike most bees, males are involved in raising the young. They will help incubate pupae by wrapping their legs around the cocoon and pumping their abdomens.
#8. Two-striped Grasshopper
- Melanoplus bivittatus
- Adults are typically 1.2 to 2 inches (3 to 5 cm) long.
- They are usually green or tan, with two pale yellow stripes running along the top of their bodies from above their eyes to the hind tips of their wings.
- They have green or buff hind tibia with black spines.
These insects are well adapted to various habitats in Montana!
Part of the reason they can call so many areas home is their diet. Two-striped Grasshoppers aren’t picky and will feed on grasses, herbaceous plants, woody plants, seed pods, flowers, and crops.
When food is scarce, Two-striped Grasshoppers will also scavenge on dead plants and animals. In addition, they occasionally resort to cannibalism!
These grasshoppers can be a lot of fun to find and catch. However, many insect lovers have found out the hard way that Two-striped Grasshoppers are quick to bite when handled. 🙂
#9. Western Conifer Seed Bug
- Leptoglossus occidentalis
- Adults are reddish to dark brown.
- The membranous portions of their wings are dark brown and form a diamond at their rear.
- Their abdomens have a yellow or orange and black pattern, but only the edges are visible until they’re in flight.
As their name suggests, Western Conifer Seed Bugs feed on the sap in conifer seeds. You can find them on a number of host plants, such as Douglas-fir, Eastern White Pine, Eastern Hemlock, Ponderosa Pine, and White Spruce.
While these insects don’t pose a considerable threat to native forests in Montana, they can be destructive in conifer seed orchards. They’ve been known to damage up to 80% of a seed crop.
If you’re looking for Western Conifer Seed Bugs, you may hear these bugs before you spot them. They produce a loud buzzing noise in flight. It’s thought that this buzzing noise, along with their brightly colored abdomens, may mimic bees, protecting them from birds.
#10. Spruce Bug
- Monochamus scutellatus
- Adults are large-bodied and black with a white spot at the base of their wings.
- Females may have white mottling on their wing covers.
- They have strong mandibles, robust legs, a spine on each side of their prothorax, and very long antennae that may be twice their body length in males.
Also called White-spotted Sawyers, you’ll find these bugs living in Montana in coniferous forests. They are most abundant where there are plentiful dead or damaged trees, like in fire-affected areas.
The reproductive methods of Spruce Bugs set them at odds with loggers.
Females use their strong mandibles to chew holes in the bark of dead or dying trees to deposit their eggs. When the eggs hatch, the larvae excavate tunnels in the wood while feeding on the inner bark, cambium, and outer sapwood.
Loggers find that these tunnels damage the wood and allow in wood-destroying fungi. However, these bugs are part of natural forest succession. They have been negatively impacted by certain logging practices like clear-cutting, which disrupts natural patterns.
Learn more about the bugs that live in Montana:
Check out these ID guides that focus specifically on different insect families in Montana.
Do you need additional help identifying insects in Montana?
If so, check out this excellent ID guide!
Which of these insects have you seen in Montana?
Leave a comment below!
