Boxelder Bugs: Accessible Ambassadors for Nature

Conservation success relies upon people feeling connected to nature.  As a result, conservation groups spend a lot of time trying to show the public how much their health and prosperity depend upon natural services and processes (clean air and water, storm surge protection, pollination, etc.).  They also try to find easy ways for people to interact with nature where they live.  The latter can be particularly difficult, especially as we become a more and more urban society.  Programs that promote and install trees, pollinator gardens, rain gardens and other tidbits of nature within our concrete jungles can all help bring nature to people.  However, I think we’re missing an easy answer that could very well be staring at you right now: the friendly neighborhood boxelder bug.

I photographed this boxelder bug on my sidewalk last week, just a few feet from where my wife first spotted it crawling on a blooming daffodil.  It was in a sheltered area on the sunny side of our house; probably warming up on a pleasant spring day.  Boxelder bugs keep their long straw-like mouth parts tucked beneath them except when they poke them into plants and seeds to feed.

Chances are, if you’re in the United States, and you look carefully through whatever building you’re in right now, you’ll find at least one boxelder bug hanging around.  If it’s a sunny day, you might be able to go outside and find some warming themselves on the south side of that same building.  Boxelder bugs make themselves easily available to us, but we have largely failed to take them up on their obvious offer of friendship.

Boxelder bugs are harmless.  They don’t bite people and they don’t cause any significant injury to plants, including the boxelder, maple, and ash trees they like to feed on.  Boxelder bugs are sometimes characterized as nuisances because they can accumulate in large numbers, especially on the sunny outside walls of buildings, or even indoors, near windows or other warm places.  And yes, large numbers of insects can create large amounts of insect poop, and that can sometimes cause some discoloration of walls or curtains.  Fair enough, but most of us put up with a lot more from kids, dogs, and/or cats without calling in exterminators.

Boxelder bugs are often seen on trees, especially maple, boxelder, and ash, where they feed on the seeds – but don’t appear to cause any problems for these trees or any other plants they feed on.  They like to overwinter in piles of plant material (landscaping mulch, compost piles, etc.) or make their ways through tiny cracks and crevices into warm buildings.

Most often, boxelder bugs get noticed during the winter when a few of them warm up enough to come wandering out of their hiding places into the living spaces of humans.  This is a perfect example of how these bugs can be ambassadors for nature.  They are quite literally little representatives of nature that present themselves to us, in a completely nonthreatening way, right in our homes.  If we can spread the word about the harmlessness of boxelder bugs, maybe we can turn these surprise appearances into positive interactions.  If we can point them toward information about the fascinating lives of boxelder bugs and other creatures, we might even start a cascade of exploration.

You’re skeptical?  Well, people are already taking an interest in boxelder bugs without our encouragement.  How do I know?  Back in February 2013, I wrote a short blog post about how glad I was to find boxelder bugs in my house because I was looking for something to photograph during the middle of the winter.  Though the post was mostly about new camera gear, I also threw in a few natural history facts about boxelder bugs, as is my wont.

The boxelder bug (Boisea trivitatta) is a true bug, and has the characteristic triangle shape on its back, straw-like mouth, and incomplete wing coverings (among other things). The “trivitatta” portion of its name refers to the three stripes behind its head.  The are categorized as “scentless plant bugs” but can release a bad tasting (and smelly) compound when attacked in order to fend off predators.  They don’t use that defense against humans, however, or at least I’ve not experienced that with the hundreds I’ve picked up to examine over the years.

Five years later, that post on boxelder bugs continues to attract a surprising number of readers.  In fact, during the last couple of years, the post has been viewed between 1000 and 5000 times every month!   It has become, by far, the most viewed post I’ve ever written, surpassing many posts I’d have predicted to have more lasting interest and value.  It has been viewed five times as frequently as “What’s the Best Time to Burn?” and almost ten times as often as “The Conservation Value of Backyard Prairies”.  I was just looking for an excuse to try out a new flash system for my camera and ended up writing the most popular thing I’ve ever written.  It’s an odd world, to be sure.

People seem to stumble onto my boxelder bug post because they are looking for information on the little insects that have shown up in their houses, and a fair number of those people appear to be looking for something beyond just how to kill them.  The comments section is full of people thanking me for providing positive information on boxelder bugs and telling me about how they are making friends with the boxelder bug(s) in their home.  This is energy that needs to be harnessed and used for good!

If people become comfortable with boxelder bugs, they might also become comfortable with other invertebrates around them, including ants, millipedes, and even (gasp) spiders.  Looking at these little creatures with interest and empathy, instead of fear or disgust, might lead them to look around for other animals to learn about.  Once they’ve gotten a pretty good inventory of what they can find in their homes and neighborhoods, they might start to wander further, and to expand upon their species of interest.  Before you know it, they’ll be amateur naturalists and conservation supporters.

Pigeons are another example of an animal living among us that is easy to observe and has plenty of fascinating stories to learn about.  Don’t believe me?  Do a Google search for “pigeon trivia”.

Boxelder bugs aren’t the only potential accessible ambassador for nature.  They happen to be handy (and cute) but there are plenty of other animals hanging around too, including both invertebrates and larger animals.  We naturalists tend to be snobbish about species like pigeons and house sparrows, but imagine what could happen if a young kid started following one of those birds around to see where it lives?  That curiosity, once satisfied, would very likely lead them to look around for other species to learn about.

If we’re going to build a constituency for nature in an urban world, it makes sense to focus more on urban and suburban nature.  Boxelder bugs, pigeons, and many other animals are right there, waiting to be noticed and learned about.  It’s important to show people what nature looks like out in the great wide open spaces, but we should probably spend more time talking about the nature living right outside, or even inside, our homes.

Who could look deeply into the four red eyes of a boxelder bug and not come away deeply moved?  (Did you notice the two smaller eyes behind the bigger ones?  I’m telling you – there’s a lot more to these little critters than you might think at first.)

Photo of the Week – July 16, 2015

Scaly blazingstar (Liatris squarrosa) is just starting to bloom in the Platte River Prairies.  It has beautiful and intricate flowers with very long anthers protruding from its tiny blossoms.  At least it usually does…

Blazing star (Liatris squarrosa)  The Nature Conservancy's Platte River Prairies, Nebraska.
Scaly blazingstar (Liatris squarrosa). The Nature Conservancy’s Platte River Prairies, Nebraska.

I was photographing some blazingstar flowers earlier this week when I saw one with a grasshopper sitting on it.  It sat still long enough for me to get a few photos of it.

Grasshopper on blazing star (Liatris squarrosa)  The Nature Conservancy's Platte River Prairies, Nebraska.
A grasshopper standing innocently(?) on top of scaly blazingstar.

Only when I looked the above photo on my computer screen did I notice the absence of most of the long white anthers I’d seen on other flowers.  Surely, I thought, it’s not a coincidence that the grasshopper is present but the anthers are not…?

Grasshopper on blazing star (Liatris squarrosa)  The Nature Conservancy's Platte River Prairies, Nebraska.
The grasshopper eating one of the long anthers.

Sure enough, looking back through my other images, I found one of the grasshopper eating an anther.  Caught red-handed!  (So to speak.)

Just because they are called “grass”hoppers doesn’t mean that’s all they eat.  In fact, many grasshoppers eat pollen and other parts of wildflowers.  Some are fairly specialized, while others are generalists in terms of the plant species they feed on.  Even among the grass-feeding grasshoppers, there is great variety in which grass species and which parts of those grasses each species eats.

For the sake of the scaly blazing star (and our seed harvest efforts this year), I hope at least some of the anthers survive uneaten so the plants can make seed.  As more flowers open, maybe their abundance will be more than the grasshoppers can keep up with.  At least in past years, we’ve usually gotten pretty good seed harvests from blazingstar, so I’m not too worried.

Just interested…

Photo of the Week – May 7, 2015

As I’ve said many times, the prairie is an ecosystem best seen up close.  You have to look carefully to see much of the beauty.  Dillon (one of our Hubbard Fellows) and I were poking around today and found this yellow wood sorrel flower.  It looked as if an artistic child had been playing with a hole punch.  There were a few scattered holes in nearby blossoms but this was the only one that looked as if it had been purposefully accented.  Any insect smarties out there know what might have made the holes?

Wood sorrel (Oxalis stricta) with insect holes.  TNC Platte River Prairies, Nebraska.
Yellow wood sorrel (Oxalis stricta) with insect holes. The Nature Conservancy’s Platte River Prairies, Nebraska.

This is the season of small statured wildflowers.  Puccoon, ragwort, locoweed, wood sorrel and many others are just starting to bloom.  Perhaps the most ostentatiously-colored of our spring flowers, however, is purple poppy mallow.  This one was just getting ready to open today.

Purple poppy mallow (Callirhoe involucrata).  TNC Platte River Prairies, Nebraska.
Purple poppy mallow (Callirhoe involucrata). The Nature Conservancy’s Platte River Prairies, Nebraska.
Purple poppy mallow (Callirhoe involucrata).  TNC Platte River Prairies, Nebraska.
Another look at the same flower.

We’ve been getting a lot of rain lately, which bodes well for a good wildflower season, at least for the next month or so.  We’ll see what kind of weather the El Nino brings after that.  We might get really wet or really dry.  For now, I’ll enjoy the colors.

Photo of the Week – November 14, 2014

The praying mantis is an impressive predator, especially when it’s a Chinese mantis the length of a ball point pen.  The ones who live around here seem to have a particular affinity for sphinx moths.  I haven’t yet watched the capture take place, but I’ve seen the mantises (mantes? mantids? critters?) devouring their fuzzy prey several times, including one I photographed last year.  Almost exactly a year later, I took the following photos at the same prairie.

A Chinese mantis feeding on a sphinx moth.  Lincoln Creek Prairie; Aurora, Nebraska.
A Chinese mantis feeding on a sphinx moth. Lincoln Creek Prairie; Aurora, Nebraska.

You can see from the photo how well this mantis can hide – it is exactly the same color as the pitcher sage (Salvia azurea) plant it was hunting on, and its shape and texture blend in perfectly.  Other mantis species around the world have even more sophisticated camouflage, which almost seems unfair.

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After watching the mantis for a little while, I decided to try out the video function on my camera.  I’ve been trying to do a little more video work lately anyway.  If you’ve always wanted to see watch a mantis eat up close – and who wouldn’t want to?? – here’s your chance.  The barking in the background is from the dogs in the nearby animal shelter who were apparently excited to watch a prairie ecologist take video of a praying mantis…

My favorite shot of the day was this last one.  There is sure a lot of personality in a mantis face…

"Just trying to eat here... do you mind?"
“Just trying to eat here… do you mind?”

Chinese mantises are, of course, not native to the U.S., but as far as I can tell from bug-smart friends, don’t seem to be having any major negative impacts (neither are they providing the kind of “pest control” they are often introduced to provide).  Some introduced species have certainly become major ecological disasters, but it seems the Chinese mantis is just a new predator for prairie insects to watch out for, and for prairie enthusiasts to enjoy watching.

(Now would be the appropriate time for entomologically-savvy readers to correct my ignorance on the topic of the Chinese mantis and its impacts.  Please do.)

Follow up to my earlier Swallows-on-Cold-Days Post

I posted earlier this week about swallows feeding from the surface of water bodies during a cold and windy day.  In that post, I included a link to a report on a mass die off of swallows and intriguing research on some rapid evolution of swallow body and wing sizes by Mary Bomberger Brown at the University of Nebraska – Lincoln.  I intended to follow up with Mary to get more information, but she beat me to it and contacted me first!  I asked for permission to share what she told me, and she agreed.

This is what Mary had to add to my short blog post:

This sort of foraging behavior is fairly common in the swallows, especially at this time of year when the birds are transitioning from migration to nesting. All of the swallows that occur in Nebraska (Bank, Barn, Cliff, Purple Martin, Tree, and Violet-green) do it. They are picking insects off the surface of the water—insects just emerging as flighted adults from aquatic instars, surface species (e.g., water striders) or moribund adults floating on the surface. Usually swallows feed on concentrations of insects caught up in thermals, mass emergences or mating swarms. Those concentrations form in the sort of weather conditions that allow thermals to form (warm, sunny, high barometric pressure days). On cool, wet, cloudy days (low barometric pressure days) thermals don’t form, insects don’t swarm and hungry swallows are left to pick insects off the water surface. With their long wings swallows aren’t particularly well-designed for that type of acrobatic flight, so, energetically, that style of foraging is probably ‘net loss’ or ‘even sum’ for them, but better than not foraging at all. You can think of swallows as being flying barometric pressure indicators—low pressure, insects down low, so swallows down low, high pressure, insects up high, so swallows up high.

 

And, about the 1996 Cliff Swallow weather kill—Cliff Swallows (and probably most swallows) typically carry fat reserves sufficient to carry them for about 4 days without feeding, beyond that they starve and die. In the last week of May 1996, the weather was cold, wet, windy and miserable across the Great Plains. It was too cold for insects to emerge and/or fly. The swallows got wet and chilled when out trying to feed on insects that weren’t available…the only successful foraging they could do was picking insects off the water surface. The swallows survived for 4 days, but on the 5th day as much as two-thirds of the population died. The swallows that survived had shorter wing and tail feathers, larger skeletons and were perfectly bilaterally symmetrical, meaning they were efficient, acrobatic fliers that could carry larger fat reserves. The swallows that did not survive were just the opposite. In the years following the weather kill those swallows and their descendants have maintained the shorter feather lengths and larger skeletons (there was significant survival selection for those heritable traits).

 

The road kill study mentioned in the last paragraph of the blog showed that the wing feather lengths of Cliff Swallows nesting on bridges and road culverts declined significantly over the past 30 years. The shorter wing feathers made them more efficient, acrobatic fliers that could better avoid being hit by cars/trucks/SUVs/RVs and survive to reproduce, producing offspring who also had shorter wing feathers. The presence of humans on the landscape with their roads and vehicles was the cause of significant survival selection for that heritable trait…a demonstration of birds adapting to accommodate anthropogenic change in the environment. The two results (bad weather and road kill) are similar (shorter wing feathers leading to more efficient, acrobatic flight and survival selection), but with very different causes, one natural and one unnatural.

Many thanks to Mary for this great information!

What Do Swallows Eat on a Cold Windy Day?

Today was a cold blustery day, on the heels of some severe weekend storms.  I went down to check on our prairie (five inches of rain, strong winds, and a tornado a few miles away) and was glad to see everything looked wet but ok – including the cattle.

As I walked through the prairie, I noticed some barn swallows flying and hovering just above the surface of the wetland/pond.  Since the temperature was in the low 40’s and the winds were howling above 30 mph, I didn’t think there was any chance there were flying insects for them to catch and eat, so I wondered what they were up to.  As I watched the swallows, I realized they weren’t just wasting energy, but instead appeared to be feeding by picking insects (I assume) off the surface of the water.  It was lightly raining and I’d left my camera in the truck, so I didn’t take any pictures, but I’d never seen nor heard of such behavior before.

About a half hour later, I had just left the prairie and was starting home when I saw a big mixed flock of cliff and barn swallows behaving very similarly in a flooded wetland about a mile from our prairie.  The rain had stopped by this time, so I pulled over and got a few mediocre photographs.

Cliff swallows feeding (apparently) on floating insects during a cold blustery spring day.
Swallows resting and flying over a wetland on a cold blustery spring day.

 

A wider shot, showing one swallow in the top right corner that might be feeding.
A wider shot, showing one swallow in the top right corner that I think was feeding.

When I got back to town, I did a little quick research and found that this kind of feeding behavior has been seen before – it was just new to me.  However, I also remembered a long cold period in May back in 1996, during which scientists documented mass deaths of swallows from starvation.  At the time, I remember being told that the birds starved because of a lack of flying insects to eat during the cold spell.  I wonder why those swallows died but the ones I saw today (two different species a mile apart) appeared to be finding food…?  I also wonder if they were catching enough food to cover the energy costs of doing so?

It’s a good day when I can learn something new AND come up with questions I can’t answer.  Anyone out there have answers for me?

 

 

 

What’s Bugging Milkweed?

As I walked a small prairie here in Aurora, Nebraska a few weeks ago, several species of milkweed were flowering abundantly, including butterfly milkweed (Ascelepias tuberosa), showy milkweed (Asclepias speciosa), and common milkweed (Asclepias syriaca).  As always, the milkweed plants were hosting a number of specialist insects that feed on them.  During my walk, the most plentiful of those insects was the large milkweed bug (Oncopeltus fasciatus).

The large milkweed bug on butterfly milkweed - Lincoln Creek Prairies, Aurora, Nebraska.
The large milkweed bug on butterfly milkweed – Lincoln Creek Prairies, Aurora, Nebraska.

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Another view
A view of the bug from the top.  The large milkweed bug somewhat resembles a boxelder bug, but is considerably larger and has more orange color on its back.  It is also larger (obviously) than the small milkweed bug, which looks somewhat similar but has two small white dots on its folded wings, as well as a different pattern of black and orange.

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Like all Hemipterans (true bugs), the large milkweed bug feeds through a long piercing mouthpart called a rostrum.  From the information I can find, the milkweed bug feeds on the seeds of milkweed, but will also feed on sap from the leaves and stems.  Interestingly, I didn’t find any information about it feeding on the nectar of milkweeds, though that is certainly what it appeared many of the milkweed bugs I saws were doing.  I watched several of them insert their rostrum into a flower and jiggle it up and down as if it were sucking the dregs of a milkshake through a straw.  The photo below shows one with its rostrum inside the flower of a common milkweed.  I’m guessing many entomologists have seen the behavior, but I didn’t find a reference to it.

Butterfly milkweed wasn't the only milkweed species with the bugs on board that day.  This one is on common milkweed (Asclepias tuberosa).
Butterfly milkweed wasn’t the only milkweed species with the bugs on board that day. This one is on a common milkweed flower and appeared to be feeding on nectar.

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About a year ago, I wrote a post about the arduous and complicated process of milkweed pollination, in which clusters of pollen called pollinia have to become attached to the leg of a visiting insect and then later detached in exactly the right place on a different flower.  If you missed that post, it’s worth a read just to appreciate what seems like a nearly impossible process – though one that has obviously worked out just fine for many milkweed species.  Several of the milkweed bugs I saw at the prairie a few weeks ago had multiple pollinia stuck to their legs, so apparently the bugs can be helpful to milkweed plants – in addition to being seed predators, nectar thieves, and sap suckers!

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In this photo, you can see pollinia (sticky clumps of pollen) stuck to two legs of this large milkweed bug.
In this photo, you can see pollinia (sticky masses of pollen) stuck to two legs of this large milkweed bug.

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I visited this same prairie again about two weeks later with my son Daniel.  Since he’s interested in insects, I figured he’d enjoy seeing all the milkweed bugs.  The butterfly milkweed plants were still blooming profusely, but not a single milkweed bug could be found…  Where did they go??  I guess it’s a good thing I took photos when I had the chance.

Photo of the Week – April 5, 2013

A few shorebirds are starting to show up along the Platte River.  The first to come each spring are usually the ubiquitous and noisy killdeer, followed by the taller and more reserved yellowlegs.

Tracks and holes in the sand where a shorebird was probing for invertebrates along the Central Platte River in Nebraska.
Tracks and holes in the sand where a shorebird was probing for invertebrates along the Central Platte River in Nebraska.

As the season progresses, we’ll see a great diversity of sandpipers, dowitchers, snipe, ibis, and many other long-legged wading birds along the sandy banks and sandbars of the river.  A few even venture into our wetlands and wet meadows, though we’ll see fewer in those areas this spring if we don’t get some significant rains soon.

One of the most fascinating things about shorebirds is that many (most?) species have flexible bills that allow them to open just the tips.  This comes in handy when they stick their long bills deep into the sand or mud to probe for invertebrates.  When they find something tasty (how do they know they’ve found one??) they can open the tip of their bill to grab it and extract it.  Opening their entire bill when it’s stuck down a deep narrow hole is not an option (if you’ve ever hand-dug a fence post hole, you know that experience), so a flexible bill tip is a pretty convenient feature to have.

Evolution in Milkweed-Eating Insects

Not many insects can feed on milkweed.  Milkweed plants produce a toxin that disables a protein in animals – a protein that facilitates important functions such as muscle contraction.  Only a small number of insect species around the world have evolved ways to get around this challenge. 

A milkweed bug on swamp milkweed in the Platte River Prairies, Nebraska.

A new study published in the journal Science looked at 14 insect species that feed on milkweed and found that each had developed one of two ways to solve the milkweed toxin challenge.  Ten of the insect species had gone through a genetic mutation that changed the protein in a way that the prevented the toxin from being able to act on it.  The other four species had created a duplicate gene in the protein that allowed it to both carry out its normal function and alter itself to avoid being impacted by the toxin.  You can see a summary of the study and a link to the full article here.

What’s most fascinating is that while these insects are only very distantly related to each other (they spanned three different orders of insects) they ended up with the same solutions to the milkweed toxin issue.  It’s not like one insect species millions of years ago developed in a way that made it immune to milkweed toxin and then begat other species of insects that retained the same quality.  These insects each developed the immunity INDEPENDENTLY.  Fantastic.

The red milkweed beetle (left) and the monarch butterfly caterpillar (right) are not closely related insects. However, both have independently evolved the same ability to feed on milkweed plants without ill effects.

Now, I have to be careful when talking about evolution because it’s easy to give the impression that these insects did something purposeful to change their bodies – they didn’t.  They changed because natural selection favored individuals with certain genetic mutations that allowed them to eat milkweed without suffering changes to essential proteins.  Unfortunately, evolution can be a hot-button topic these days, and one of the biggest reasons is that many people have a fundamental misunderstanding of how evolution actually works.  If you’re interested, here is a link to website with a very brief but clear explanation of the process.

In the case of milkweed-eating insects, it’s easy to see that being able to eat a plant that competing herbivores can’t eat is a major advantage.  Somewhere in history, a few lucky individuals ended up with a random genetic mutation that allowed them to eat milkweed without ill effects.  Those individuals got a sudden leg up on their competition and, as a result, were more likely to survive and reproduce.  What’s crazy and fun in this case is that multiple unrelated species ended up with similar genetic mutations of their proteins.  They each accidentally “found” the same path to success.  It’s a great world we live in.

A Soldier Beetle Occupation

Everywhere I look, I see soldier beetles.

They’re in my yard, they’re in my prairies, and now I think they’re getting into my head (figuratively speaking).  The linden tree in our front yard is blooming this week, and every flower is loaded with feeding and mating soldier beetles.  Over the weekend, my son and I went to our family’s prairie and it seemed there were soldier beetles on every plant! 

While soldier beetles are predators, they also feed heavily on pollen.  This one is feeding on sensitive briar – aka cat’s claw (Mimosa quadrivalvus) at our family prairie in Hamilton County, Nebraska.

Daniel and I were at the prairie to look for musk thistles (only found one) and check the cows (found them all).  After we accomplished those two objectives, I grabbed my camera to take advantage of the diffused light from the bright overcast skies and Daniel headed to the pond to chase frogs.  Dan didn’t catch any frogs, but I managed to get some decent shots.  Some of those photos included soldier beetles as the primary subject – they were easy to find.  Other photos included soldier beetles accidentally.  In a few cases, I didn’t even know the beetles were in the photo until I loaded the images onto the computer back at home.

While they are sometimes misidentified as lightning bugs, these are soldier beetles feeding on the pollen of a black-eyed Susan flower.  I photographed these on purpose…

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When I photographed this fly feeding on a daisy fleabane flower, I didn’t even see the soldier beetle in the background – though I shouldn’t be surprised it was there…

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These regal fritillary butterflies are out very early this year, and are fortunate that milkweed flowers are also out early. I was photographing the butterflies (including the variegated fritillary), but ended up with soldier beetles in the photo as well.

When I zoom in on the butterfly photo above, I can count five soldier beetles. Can you find them all?  One is particularly tricky to find because only the back half shows.  I think I see the leg of another, but I can’t tell for sure.  If you click on the photo and then click again, you’ll get a zoomed in image (if your computer works like mine).

If you want to learn more about soldier beetles – including how to differentiate them from lightning bugs – click here.

I wonder if they’ll chase away the moths…