American Eyespot Lady Beetle

Lady beetles introduced form Asia are slowly replacing our native species. But this beautiful native, the American eyespot lady beetle (Anatis mali) is holding her own. Most lady beetles dine on aphids, and this one specializes in aphids that live in trees.

She's our largest native ladybug, featuring 18 or so black spots surrounded by beige rings. These spots are set against a background color that darkens with time, starting out yellowish and turning reddish-brown as she ages.

American eyespot lady beetles range across an east-west swath of North America from Alaska to Maine, dipping down across most of Montana.

My Trees Have Fleas

Tiny, iridescent blue and green Alder Flea Beetles on the bark of my alder tree

Living this far into the great white north, we've never had a problem with fleas on our dogs. But this year we have fleas on our trees instead. Our new fleas are small but very handsome, in shimmering shades of iridescent blue and green.

A clump of trees along the lakeshore is currently enduring an outbreak of Alder Flea Beetles (Macrohaltica ambiens or Altica ambiens, depending on who you read). Flea Beetles are small leaf beetles (less than 1/4 inch long) that sport enlarged femurs on their hind legs - muscular thighs that are used to leap away from danger. I pestered a few of our adult beetles long enough to verify that, indeed, they are excellent leapers.


Alder Flea Beetle larvae on a leaf, including
one with a fungal infection (whitish area)

Back in July, these same alder trees were covered with hundreds of small, black, caterpillar-looking larvae. But they lacked the pudgy prolegs of true caterpillars, which was enough to tell me that they were really beetle larvae, but not enough to tell me who they were. I kept watching the alder trees for more clues.

The larvae spent a several weeks eating almost every single leaf in this clump of trees, leaving mostly brown leaf skeletons blowing in the wind. In August they all crawled down out of the trees, headed uphill, and disappeared into the soil to pupate into adults.

In September, the adult beetles started showing up in the same alder trees and feeding on leftover and replacement leaves. They numbered into the dozens per smallish tree, but now that it's October the adults are starting to disappear again, back into the soil for winter. They'll emerge in early spring, mate, and lay their eggs in the soil around these trees.

For reasons unknown, these infestations only last for a few years, and the alder trees seem to suffer only minimal damage. Fungal attacks on the larval seem to play a role in checking the beetle outbreaks, and they don't spread very far because most Flee Beetle species only feed on a small handful of closely-related host plants. Some are beneficial as well, including three species of Flea Beetles that were successfully introduced into eastern Montana and South Dakota as biological control agents against leafy spurge, an invasive non-native forb.

While my Alder Flea Beetles are just a temporary nuisance, other Flea Beetle species can cause considerable damage to western crops, especially rapeseed and canola. There are also Potato Flea Beetles (potato, tomato, nightshade family), Apple Flea Beetles (primrose, grape, crabapple), Willow Flea Beetles (willows), and Cabbage Flea Beetles (wide range of cruciferous plants), among many others.

Now if I could just find a Cabbage Flea Beetle that specializes on my gastero-nemesis, cauliflower, I'd consider that one to be among the highly beneficial species.

Hairy Pine Borer

The aptly-named Hairy Pine Borer (Tragosoma harrisii)

Most of our native beetles are stunningly handsome, which makes this homely one stand out even more. The Hairy Pine Borer (Tragosoma harrisii) is one of our native long-horned beetle species - and easily the ugliest beetle I've ever crossed paths with.

These beetles live in high-elevation pine forests across North America, from northern Mexico to northern Canada. Males and females both sport a shaggy collar of reddish hair on the thorax, between their head and abdomen.

The adults hide during the day but can be attracted to ultraviolet lights at night. They breed in dead pine and fir stumps, where their larvae bore into the rotting sapwood. Thus, they are seldom seen at any age.

Somehow, this sight of this beetle has me imagining an elder Albert Einstein - as a redhead. The eyes are different, yes, but the bald forehead and shaggy mane fit the description for both animals. Similarly, I used to hope that the shaggy red mane of my teenage years made me look uber intelligent, but now I know that it really made me look like a boring bug instead.

BEYOND THE BOYS: Way waaaaaaaaaaaay over on the other end of the continuum, you can join "The Bug Chicks" (two Oregon entomologists and teachers) as they travel across the U.S. with a vintage sofa to show us the fascinating world of bugs - right here in our own big back yard. Your support will help promote "positive programming, science, female role models, and fun, educational content." Sounds waaaay better than hanging with the boys...

Flat-headed Borer Beetle

Adult Western Sculptured Pine Borer

If you live in the sticks, literally, then you have probably met this large, native beetle. The Western Sculptured Pine Borer (Chalcophora angulicollis) is one of the so-called "metallic" or "jeweled" beetles that lives just about everywhere that pine or fir trees grow. This is the only westerner in the group, but four related species chew through the forests of eastern North America.

The beetle's "sculptured" back

Adult beetles fly and mate in summer, and females lay their eggs on tree bark. The western adults eat leaves while their larvae eat wood, especially Douglas fir and ponderosa pine. Their common name, "flat-headed beetle," comes from these legless white grubs that are t-shaped, sort of like horseshoe nails. After hatching, the larvae chew their way through the tree's protective bark and into the living cambium layer just below, where they tunnel for food. They remain as sawdust-producing larvae for 1-2 years and go through a dormant pupal stage before transforming into the winged adults that we see.

Many of the wood-boring beetles engage trees in a form of complex chemical warfare. The adult beetles key in on scents produced by injured trees, and on the communication pheromones produced by other beetles. Some species attack en masse in order to overcome the tree's defensive measures.

Females are attracted to injured and drought-stricken trees, which emit a defensive compound (myrcene) when stressed. The tree bleeds sticky sap to "pitch out" the first few beetles that attack. But the females make a pre-emptive strike by releasing pheromones to attract additional male and female beetles to the tree.

Male beetles are drawn to the injured tree by the pheromonal message sent out by early-arriving females. Once they locate the tree, males release their own pheromone which attracts even more beetles to the front line. After mating, however, males and females both change their chemical signals. Now they release pheromones that interrupt further attraction by more beetles.

There are entire cohorts of native insects like these that are drawn to forests stressed by drought and scorched by fire. Before we started warming the global climate and putting out forest fires, these insects only affected forests on a small, localized scale. But we have unintentionally tipped the scales to favor these insects, and as a result we are now losing forests on a far larger scale.

Sex, Lies & Triungulins - The Blister Oil Beetles

Male Blister Oil Beetle (top) romancing a female

( Romantic Valentine's Day issue - not! ) 

Gentle readers, rest assured that I am not devious enough to make up a tale this tall. No, the real-life story of some Blister Oil Beetles is almost beyond belief without any enhancement by me, your humble naturalist.

With that admonition, here we go. Through the creative use of cooperative behavior and sex pheromones, some species of Blister Oil Beetle (Meloe spp.) fool some Solitary Digger Bee species (subfamily Apinae) into delivering the beetles' larvae to the bees' nests, where the beetles eat the bees' food and the immature bees. And that's the censored version. Read no further unless you have a strong stomach and an open mind.

All of the Blister Oil Beetles that I've seen look like big black ants with extremely large butts (abdomens, actually). These are the adults, looking to mate and bury their eggs.


Male bleeding yellow, toxic cantharidin

When disturbed, these adult beetles employ a strange but effective defense. They bleed oily droplets between their leg joints and body segments that contain the highly-toxic chemical, "cantharidin."

Sound familiar? Cantharidin is a chemical compound secreted by several beetle species - and one fly, the infamous "Spanish Fly" (Lytta vesicatoria). That's right, the alleged aphrodisiac of Cheech and Chong fame. In reality, cantharidin causes painful blistering and swelling of human skin. If ingested, it causes severe burning in the urinary tract and can easily be fatal.

How these beetles synthesize this poison is unknown, as is how they remain unaffected by it. But it's the young larvae of these aphrodisiac-producing, big-butt beetles who take sexual deception to a whole 'nuther level.


Males (top) have kinked antennae

Blister Oil Beetle eggs hatch into dozens of small, quick-crawling, dragon-like larvae called "triungulins." The flightless triungulins release a chemical cue into the air that directs them in a cooperative behavior that is right on the edge of believability. They climb a nearby plant and mass together at the top of a single stem, where they release a second chemical that is almost identical to the sex pheromone released by female Digger Bees to attract males.

A male Digger Bee is chemically and visually attracted to this vibrating hunka' beetle larvae, and he lands to mate with "her." While he's busy (technical term, "psuedocopulation") many of the larvae latch onto tiny hairs on his belly until, either finished or flustered, he flies off in search of more "female bees."

Subsequently, each time he finds a real female bee to mate with, a cluster of beetle larvae disembark and clamber aboard the female. The impregnated female Digger Bee will soon dig a cave for her eggs and provision her young with honey and pollen. She also unwittingly delivers the predatory beetle larvae to her nest, where they'll settle in and proceed to eating the pollen and, often, eating her young bees as well.

Eventually, the well-fed triungulins in the bee nests will pupate in the soil and emerge as adult Blister Oil Beetles - with big butts. Brother and sister beetles find each other, mate, lay eggs, and the whole story gets all strange again.

If you don't believe me - and I don't know why you should - you can watch a short but stunning video of the Blister Oil Beetle's life cycle here (at the amazing ARKive site).

I hesitate to mention a different beetle species that grapples with Blister Oil Beetles in order to lick off the toxic cantharidin. The male offers the toxin as a nuptial gift to his mate, and she uses it to cover her eggs for protection against predation. No, that tale might actually be beyond belief.

Female Blister Oil Beetle (Meloe impressus) searching for a mate and/or a place to bury her eggs.

Home Sweet Crypt

( Fair warning! Creepy-crawly Halloween issue! )

It was a warm summer afternoon when my brilliant friend, Bob, accidentally buried himself about eight feet deep, pinned beneath a plastic 1,000 gallon water tank that he was installing. Alone. Fortunately, the tank was empty and Bob slowly dug his way to the surface, living another day to tackle yet another home improvement project. As humans go, Bob is one of the most unusual specimens I've ever known.

As bugs go, one of the most unusual specimens I've ever met is a handsome, black and orange insect known as the "Sexton beetle" (Nicrophorus vespilloides, in my encounter).

Adult Sexton beetle (Nicrophorus vespilloides)

Among us humans, the "Sexton" was the church employee whose duties included grave digging. The Sexton beetles were so named for their habit of burying their young with a small, dead animal. But this odd behavior begins to look pretty smart when you start digging up some of their other habits.

Like some of those southern tent-revival preachers, Sexton beetles can seem caring and creepy at the same time. They bury the dead with utmost care and cleanliness. They also provide bi-parental care (male and female) to their young - an extremely rare behavior in the insect world - while condoning cannibalism to keep their family size manageable. And to top it off, these beetles fly around at night with large, red mites clinging to them, which they shuttle from carcass to carcass like crowded, red-eye commuter flights.

These are large, handsome beetles, but they're mostly nocturnal and seldom seen (which also sorta' describes Bob). The Sextons make a living by taking care of small deceased animals, like birds and squirrels. Their antennae tips are enlarged and flattened to help them follow the irresistible aroma of cold cadaver (actually, three different sulphur-based compounds) wafting on a warm summer breeze.

The first male beetle to arrive at a fresh carcass defends it from other males while waiting for a female to arrive. If she's late, he assumes a stiff-legged posture on top of the deceased and releases a he-beetle pheromone to help bring her home. Sometimes, a male Sexton assumes this posture without actually finding a body, and proceeds to mate with any female Sexton who lands to inspect his larder. But only the last mating prior to egg-laying will beget her offspring.

Multiple Sexton beetles might cohabitate on a large carcass, but normally there is just one parental pair per modest cadaver. Both male and female excavate a grave beneath the body, or drag the departed off to softer ground if necessary. They remove feathers from birds and hair from mammals, roll the deceased into a ball, and carefully cover the naked body with special anti-fungal oral and anal secretions to slow down decomposition.

While helping her mate cover their new pantry with dirt and leaf litter, the female Sexton takes a break to lay her eggs in the soil immediately above the carcass. Both parents guard the crypt, and they make a small depression in the top where their grub-like larvae will gather after hatching, a day or two later.

Among larger Sexton beetle species, the young are completely dependent on parental feedings. The smaller species often feed their young, but their grubs can also fend for themselves. In general, adult males tend to guard more while females tend to feed the young more, but if one adult dies the surviving adult will successfully perform both duties.

Both parents feed their begging larvae chewed-up and regurgitate meat, while also working to keep the competing flies and maggots at bay. If too many fly maggots emerge, and the amount of food available becomes insufficient to provide for the whole Sexton family, the beetle parents will consume some of their own larvae ("filial cannibalism") to ensure that their remaining offspring grow up strong.

Mite hitch-hikers on a Sexton beetle

Sexton beetle parents also deploy a red army that helps them deal with the nefarious flies. Fly maggots are a favorite menu item for those hitch-hiking mites that cling to the adult Sexton beetles.

Upon arrival at a new carcass, the adult mites will disembark, partake of the bounty, flirt, mate, and eventually lay their own eggs alongside the Sexton's eggs. After the mite eggs hatch, this new generation of mite larvae quickly grow into non-feeding "deutonymphs," and it's these teenagers that hitch a ride to the next cemetery. Most of the early mites will gravitate to the adult male Sexton beetle, who departs from the crypt several days before his mate. Late-developing mites who miss both flights (about 14% of them) must wait for the young Sexton larvae to pupate and depart - which puts the late-blooming mites at a career disadvantage. 

About a week after hatching, the well-fed beetle larvae wanders off on a warm afternoon and buries himself in the surrounding soil to pupate. About two weeks later (or the following spring, for some Sexton species) a new adult beetle slowly digs his way to the surface, collects a few hitch-hikers, and flies off to sniff out a new home improvement project.

(Behind the beetle: I felt disappointed that I didn't get to count the mites on this fellow before he flew away. He was probably toting 8-10 mites, but I've seen photos of Sexton beetles covered with a dozen or more mites - now there's a Halloween costume idea!)

A Tar Sands Beetle, eh?

A male White-spotted Sawyer beetle

Our local papers report almost daily on the numbers of young males flocking to eastern Montana's oil fields - and the problems associated with that demographic. But they never mention the White-spotted Sawyers (Monochamus scutellatus).

Just across the border in Alberta, they call this common long-horned beetle the "Tar Sands Beetle" because it flocks to places where natural tar (bitumen) is exposed. Near Fort McMurray, the Athabasca River cuts a channel through a bitumen-rich layer, and sunny summer days bring swarms of native Sawyers.

Why are beetles attracted to tar? Why alcohol, of course.

When exposed to sunlight, the natural bitumen emits terpineol vapors. Terpineol is a naturally-occurring alcohol that, it just so happens, is also found in pine oil. Pine oil is something we've used for years in deodorizers, disinfectants and antiseptics.

But terpineol vapors are also emitted by conifer trees in distress - burned, wind thrown, and fresh-cut live trees. And the White-spotted Sawyers seek out distressed trees as a good place to lay their eggs. After hatching, the grub-like larvae spend two years chewing their way around inside the log. This chewing can be disconcertingly audible to new log home owners, and it can decrease the wood volume by up to five percent.

The beetle itself seldom kills a tree, but problems associated with the young's lifestyle can. The grub's gallery and hole provides fungi with a point of attack. After a fire, this is a good thing because the fungi hasten wood rot and decomposition. But it's not so good for, say, a logging company because fungal "damaged" wood looses value and makes it harder to keep a ledger in the black.

Male Sawyers, like the one above, are all black except for a small white triangle (the "scutellum") at the base of their wing covers (click photo to enlarge). Male antennae are twice as long as their body, and twice a long as a female's antennae. Females might also be shiny black, but sometimes they have extra white spots on their wing covers. Adult Sawyers emerge between July and September to mate and lay their eggs on trees that smell good - to a Tar Sands beetle.

Artists and Other Aliens

I'm not outstanding in my field, but I do stand out in my neighborhood. All of our he-man neighbors retired from regular jobs, and none of them know what a starving artist does "for work" or how an out-of-towner (from 20 miles away) gained a foothold in their conservative community. Curiosity got the best of one fellow recently.  

"Why did John mow all the grass but not the thistle?" he asked. "Butterfly habitat," my wife answered. "Ohhhhhh." That explained one of my odd behaviors.

Earlier this summer summer, I started counting the different animals found on one small thistle plant. I quickly racked up a more than a dozen species of spiders, flies and beetles - and the ants, aphids and butterflies weren't even around yet. It struck me, this plant is a little "Thistle Universe." How could I mow it down?

I didn't recognize many of these little "bugs," so I submitted photos to BugGuide.net for expert identification. The results were a big surprise - the first three insects were all non-native, alien species. One fly and two beetle species native to Europe were already living in our neighborhood, with histories much more intriguing than my own.

Female Bull Thistle Gall Fly

Bull Thistle Gall Fly (BTGF)

The colorful, 1/4" Bull Thistle Gall Fly (Urophora stylata) is a small fruit fly that lays its eggs in - you guessed it - Bull Thistle (Cirsium vulgare). Two to 30 larvae form a walnut-sized gall in developing seed heads, and their presence can reduce thistle seed production by 60%.

For biological weed control, BTGFs from Europe were introduced to British Columbia in 1973 and Quebec in 1976. Since then, many states have introduced BTGF as a host-specific biological agent to control this non-native thistle: Washington (1983), Colorado (1985), Oregon (1988), Montana (1989) and California (1993). In some areas, BTGF larvae now exist in 60-90% of the bull thistle seed heads.

Each June, adult BTGFs pupate from last year's thistle seed heads, but these adults will only live for two months. After mating, the females lay their eggs on this year's seed heads. The larvae hatch a week later, burrow into the seed-producing tissue, and induce the thistle plant to grow a gall. The larvae overwinter in this gall, and they'll emerge as adults next June.

Thistle-head Weevil (THW)

The accidental introduction of 10 Eurasian thistle species to N. America had become an agronomic problem by the mid-1950's. So the Canadian and U.S. departments of agriculture studied these thistles in France from 1961-66, and they identified more than 120 thistle-associated insect species. They chose the Thistle-head Weevil (Rhinocyllus conicus) as having a high potential for use as a biological control against the non-native thistles in N. America.

Two Thistle-head Weevils in combat on a thistle stalk

After some field testing, these 1/4" green and black beetles were released in two Canadian provinces (1968) and four U.S. states (1969), including the Gallatin Valley in south-central Montana. Initial results looked good. After five years, the Gallatin Valley weevils had expanded over almost 800 square miles, and seed head production was reduced in some exotic thistles.

But contrary reports slowly began to surface. In several locations, these THWs developed a taste for some of our native thistles, which were already controlled by native insects and were not considered a problem. By 1976, 41% of the native Wavyleaf Thistle (Cirsium undulatum) examined in Montana had eggs from the imported weevils, and their larvae were found in 16% of the seed heads.

By 1985, researchers had found THW larvae in the seed heads of 17 native thistle species, including four rare species. In Nebraska, it was 20 years after the initial releases before the weevils switched from eating exotic thistles to native thistles. As the weevil population grew exponentially, and the native thistle populations shrank, the number of thistle-associated native insects also dropped dramatically in some locations.

In spite of the detrimental effects on native thistles and insects, the non-native Thistle-head Weevil is still promoted as an acceptable biological control of non-native thistles. Adult weevils are sold commercially, and hundreds of additional releases have occurred across the U.S.

Thistle Tortoise Beetle (TTB)

Adult Thistle Tortoise Beetle (click to see her foot)

The first two stories are interesting, but the most intriguing insect found in my yard (so far) was the Thistle Tortoise Beetle (Cassida rubiginosa). The adults and larvae bear no resemblance to each other at all, and they have some unsanitary behaviors that only a naturalist could love. In other words, I won't be pointing them out to my conservative human neighbors.

Like some of its little neighbors on my thistle plant, the TTB hails from Europe and has been introduced to N. America to control exotic thistles. But unlike the weevil, our native insects keep TTB populations from building up to damaging levels.

The adult TTB is a leaf beetle that looks sort of like a 1/4" tiny turtle. Accidentally introduced from the Mediterranean, it was first discovered in N. America in Quebec in 1902. It slowly spread east and west in Canada, and southwards into the U.S.

After arriving on its own, TTBs were purposely introduced to Virginia as a biological control for Musk Thistle (Carduus nutans) in 1969 (along with the Thistle-head Weevil). But they soon discovered that TTBs also had a taste for a number of native thistles, and the species is no longer approved for use in biological control. Still, they persist in low numbers across the northern U.S. - including the exotic thistle islands in my Montana yard.

The turtle-like adults overwinter in the soil, emerging in spring to mate and lay clumps of eggs on the underside of thistle leaves. The protective female lovingly covers her eggs with a layer of excrement. This is where the unsanitary association between excrement and young TTBs begins.

TTB eggs hatch into larvae that are best described as tiny, spiny, oval-shaped dragons. The lateral spines are augmented with a larger caudal fork that points upwards. The larvae go through five moults ("instars"), and after each moult, the dead skin is collected on the fork and held over the body as a shield from predators. As if the spines, forks and dead skin aren't deterrent enough, the TTBs also collect their excrement in this dead skin shield.

The Thistle Tortoise Beetle's shield has fascinated Naturalists since the early 1700's, and they have come up with many names for it. The names include "stercoraceous parasol" from 1869 (rough translation, "poop vomit umbrella"), "faeces pack" (1915), and "frass mask" (1935). The current name for this unusual structure is "fecal shield," from 1967.

Larval Thistle Tortoise Beetles with fecal shield (right) and without (left)

Maybe my older, more utilitarian neighbors would appreciate what these three exotic insect species do "for work," helping to keep non-native thistles in check. People appreciate history more as they age, so maybe the neighbors would like to learn about the historical "man-vs-nature battles" that brought these creatures to their neighborhood. And just maybe, when my neighbors were younger, the odd behaviors of these insect residents would have caught their fancy.

Maybe, but probably not. Poop-covered bugs - like artists - aren't always easy to understand.

No Problem Here

A Lady Beetle (family Coccinellidae) maneuvers on the terminal spine of a thistle leaf - upside down and without opposable thumbs.