As a nature lover living in California, I’m endlessly fascinated by the state’s incredible biodiversity. Over 20000 insect species call California home, including over 1,400 different types of beetles. From tiny fungus beetles just a few millimeters long to massive rhinoceros beetles over 6 cm, beetles come in a staggering array of shapes sizes and colors.
In this article, I’ll highlight some of the most common, eye-catching and unique beetles found in California. Whether you’re an aspiring entomologist or simply want to identify that unusual bug in your backyard, read on to learn more about these captivating insects.
Beetles belong to the incredibly diverse order Coleoptera accounting for 25% of all known lifeforms on earth. With over 400000 species named so far, as a group they far outnumber all vertebrates combined.
What defines a beetle? They have a pair of tough front wings that protect delicate flying wings folded underneath. The thick front wings are called elytra and make a straight line down the beetle’s back when closed. Beetles also have biting mouthparts and go through complete metamorphosis with four life stages – egg, larva, pupa and adult.
Ground Beetles
One of the most commonly encountered beetles in California are ground beetles in the family Carabidae. Over 500 species are found here, inhabiting fields, forests, beaches, gardens and backyards These swift-moving beetles are typically black or metallic, from tiny 3 mm Pterostichini to imposing 35 mm Calosomas Favorites include elegant iridescent green and bronze caterpillar hunters in the genus Calosoma. Keep an eye out for these bright beauties in spring and summer as they chase down prey at surprising speeds.
Ladybugs
No list of California beetles would be complete without mentioning ladybugs. While the convergent lady beetle is the state insect, nearly 200 ladybug species inhabit California. Most ladybugs have round, dome-shaped bodies and spot patterns that warn predators of their foul taste. Look for twice-stabbed lady beetles, parenthesis lady beetles, transverse lady beetles and many more. Ladybugs are beloved beneficial insects thanks to their appetite for soft-bodied pests like aphids.
Scarab Beetles
Scarabs in the family Scarabaeidae include some of the most spectacular beetles in California. Iridescent green figeater beetles feed on ripe fruit and visit backyard orchards and gardens. Massive rhinoceros beetles like the unicorn beetle sport an impressive horn and can grow over 6 cm long. Tiny jewel scarabs glitter like precious metals as they feed on flower pollen. Other favorites are bumbling flower beetles and rainbow scarabs that brighten summer days with their colorful, fuzzy bodies.
Longhorn Beetles
The longhorn beetle family Cerambycidae includes many elegant species dressed in striking patterns. Look for white-spotted sawyer beetles, California prionus beetles, cottonwood borers and more. Longhorns like valley elderberry longhorned beetles have incredibly long antennae. As larvae, these wood-borers carve meandering tunnels into dead wood; adults emerge to mate and start the cycle again.
Darkling Beetles
Darkling beetles in the family Tenebrionidae prefer hot, dry habitats like deserts and scrublands. Check under rocks or logs to uncover colorful species like desert stink beetles, fringe-winged blister beetles and clown beetles. Darklings are masters of water conservation with specially adapted body shapes and the ability to absorb water vapor. Prey often includes dead insects and plant material.
Glowworm Beetles
One of the most magical beetles found in California are glowworms in the family Phengodidae. Flightless females resemble larvae and glow to attract flying males. Peak glowing season is spring; females perch on vegetation waiting for mates. Southern California is home to two species – the California glowworm and the railroadworm. Glowworms as larvae are predaceous, feeding on snails, worms and insect larvae.
Metallic Wood-Boring Beetles
Jewel-like metallic wood-boring beetles in the family Buprestidae add sparkling color to sunny days. Look for them visiting flowers and foliage. Larval buprestids tunnel into trees and logs; common hosts in California are pine, willow and oak. Jewel beetles can be very host-specific – the California five-spined engraver exclusively infests scrub oak. Other handsome buprestids are gold-spotted oak borers, golden jewel beetles and western buprestis.
Rove Beetles
Rove beetles in the family Staphylinidae are short-winged scavengers often found under debris. There are over 3,000 species in North America; favorites include devil’s coach horses with imposing mouthparts and huge rove beetles over an inch long. Rove larvae pursue prey like fly eggs and small worms. Adults clean up decaying matter, controlling pests in the process. Other roves like owlflies parasitize bee nests.
Lightning Bug Fireflies
California’s own fireflies are Wingless Glowworm beetles in the family Phengodidae. Females resemble larvae and glow yellow-green at night, perching on low vegetation. Males fly towards this beacon seeking mates. Peak mating season is April to June. Glowworm larvae prey on invertebrates in damp areas.
Though not true fireflies, California Glowworms and larval Railroadworms create similar bioluminescent magic on warm nights. Favorite places to spot their glow include Big Sur, Baja and the Sequoia National Forest.
Tiny Bark-Gnawing Beetles
Some of California’s most overlooked beetles are tiny bark-gnawing beetles in the family Trogossitidae. Just 2-3 mm long, these oval beetles live in dry dead wood with bark still attached. Their small size allows them to take advantage of tight spaces and small cavities. Prey includes fungus, mold and dead insects. Fun genera to look for are Peltis, Acalanthis, Tumidus, and Tenebroides.
Predaceous Diving Beetles
Watch for predaceous diving beetles (family Dytiscidae) cruising freshwater habitats like ponds and streams. Streamlined bodies and oar-like legs make them powerful swimmers in pursuit of small fish, tadpoles and aquatic insects. California favorites include the giant diving beetle which grows over 35 mm long. Margined rove beetles in the genus Ooctonus skim pond surfaces similar to water striders hunting for mosquito larvae.
Carrion Beetles
Carrion beetles like burying beetles (Silphidae) and sexton beetles (Nicrophoridae) arrive just after death to recycle decaying remains. Adults of these important scavengers lay eggs on carcasses; larvae consume flesh. Bright orange burying beetles cooperate to bury small vertebrate carcasses. Metallic green sexton beetles prepare rodent nests to attract mates and raise offspring. Without these beetles, corpses would linger much longer in the environment.
Whimsical Weevils
Lastly, weevils in the family Curculionidae are endlessly fascinating. California is home to acorn weevils, picnic beetles and Fuller rose beetles. Their snouts are perfectly adapted for drilling into plants, nuts and fruits. Clever camouflage like the giraffe weevil’s extended neck disguises this beetle as a leaf bud. Though some weevils are agricultural pests, most fill an important niche as decomposers.
From tiny fungus beetles to massive rhinoceros beetles, California’s beetle biodiversity is simply stunning. Grab a field guide or use iNaturalist to document beetle species in your region. You’ll be amazed at the diversity right under your nose. Each time I venture out with my hand lens I discover new species to appreciate. I hope you’ll join me in watching for these charismatic insects that enrich our natural heritage.
Location: native to western North America
Impact significance:
Hosts: Fageceae spp. including Quercus agifolia, Q. kelloggii and Lithocarpus denisiflorus
Biology: Adult ambrosia beetles attack host trees that are dying, weakened, diseased, or recently dead. Males initiate attack by constructing a gallery and a nuptial chamber in the sapwood. After joining the male in the nuptial chamber, the couple mates and the female introduces a symbiotic fungus, Monilia brunnea from mycangia. Both sexes then excavate two to four diverging galleries in the sapwood. Eggs are laid in niches cut into the walls of the galleries, which are enlarged into cradles by larvae feeding on the fungus.
Damage: The pinhole damage in the wood and the dark staining resulting from the fungal growth in the galleries, degrade wood quality of lumber and other products.
Ips Beetle
Status: Native
Hosts (in California): All pine species are attacked
Biology: There are two generations, in dry years three or even four generations may occur. Adults become active in early spring, infesting fresh slash or winter-damaged trees. Attacks are initiated by the male beetle, which construct the nuptial chamber beneath the bark. Females are attracted to the male pheromones and after mating, egg galleries radiate from the nuptial chamber. Unlike many other bark beetles egg galleries are free from boring dust and frass. Beetles prefer fresh from logging, construction activity, or natural events, but living trees may be attacked during outbreaks.
Damage: In standing trees, fading tops of large trees or whole crowns can be an indicator of Ips spp. Other external evidence consists of accumulation of boring in the bark crevices and at the based of the tree. Occasional pitch tubes can be found on the trunk. Most pine engraver problems are associated with disturbances such as windthrow or ice breakage, drought, thinning, logging, fires, road construction, etc.
Ips calligraphus and Ips grandicollis galleries in windthrown longleaf
Ips calligraphus and Ips grandicollis galleries in windthrown longleaf 1/2
New species of beetle named after former California governor Jerry Brown
FAQ
What are the big beetles in California?
The California Prionus beetle, Prionus californicus, can be as large as two to two-and-a-half inches.
What are the tiny beetles in my house in California?
In California, 3 species of carpet beetles cause serious damage to fabrics, carpets, furs, stored food, and preserved specimens such as taxidermies: the varied carpet beetle (Anthrenus verbasci), the furniture carpet beetle (Anthrenus flavipes), and the black carpet beetle (Attagenus unicolor).
What does a California beetle look like?
Adults are large reddish brown beetles (1 to 2 inches in length) with smooth and shiny elytra. Adults are sexually dimorphic with males being smaller (1 to 1-3/4 inches) than females (1-1/2 to 2-1/4 inches) and having antennae that are much more strongly serrate than those of females.
What are the round black beetles in California?
Adult carpet beetles are small (about 1/8 to 1/10 inch long) and have round bodies and short antennae. They range in color from black to a mix of white, brown, and yellow, depending on the species and age. Larvae are slightly longer than adults and look like fuzzy or hairy maggots.
Are there beetles in California?
California has many beetles belonging to different families, mainly inhabiting various parts of South California. The pine sawyer and figeater are the largest beetles here mostly dwelling in the southern parts of the state. The northern part also has its share of beetles, like the pictured rove beetle.
What do beetles eat in California?
The larvae hatch and feed on soft-bodied invertebrates, including insect larvae, earthworms, and snails. They are common in oak woodland areas from spring to early summer. We have comprised a list of the most common beetles you will encounter in California, helping you identify them with ease.
Are red eared blister beetles common in California?
Red-eared Blister Beetles (Lytta auriculata) can often be encountered in California. They are found in both North America and Central America. These beetles grow to just under two centimeters in length and are commonly encountered from February to July. 34. Cosmopolitan Ground Beetle
What are the most common insects in California?
Butterflies are another type of common insect in California! The most common butterflies in California are the Monarch Butterfly – Danaus plexippus. If you want to attract butterflies and other pollinators then read my article 50 USEFUL Plants that Attract Pollinators. Butterflies have red-orange brilliant wings with white spots and black veins.
Are there beetles in North Carolina?
The northern part also has its share of beetles, like the pictured rove beetle. The carpet beetle species make their presence felt throughout the state infesting woolen garments, upholstery and so on. Largest Beetles: Pine Sawyer Beetle, Ten-lined June Beetle, Figeater Beetle
What is a darkling beetle?
Woolly Darkling Beetle The Woolly Darkling Beetle (Eleodes osculans) is a ground beetle and is common in coastal southern and central California. They are found in wooded areas of chaparral and Baja California. They have a distinct defense posture, raising their hind end and secreting a foul odor.