Jagged Ambush Bugs: Homicidal Killers in the Flowers

Tis the season for meadows full of beautiful native wildflowers, such as this tall ironweed, Vernonia gigantea. Various goldenrods, asters, and other flowers of fall are starting to come on strong, too.

While a flower-filled field may look peaceful, in reality scores of wee killers lurk among the blooms. A flower can be a very dangerous place for a nectar-seeking pollinating insect. I did a pretty intensive field trip through several southeastern Ohio counties last weekend, and managed to find a number of specimens of one of my favorite killers in the flowers, the Jagged Ambush Bugs in the genus Phymata.

An ambush bug sits, rather uncharacteristically conspicuously, on the magenta flowers of ironweed. It is like a little gargoyle. Note the powerful raptorial forelegs. If a small bee, wasp, fly, or anything that can be overpowered lands here, it is likely doomed. With a quick lunge, the ambush bug will seize the victim, and then punch it with a syringe-like proboscis. Toxins in its saliva quickly immobilize the victim, and digestive enzymes rapidly decompose its innards. When a nice, slushy consistency has been reached, the ambush bug slurps out the contents.

The keen observer of Jagged Ambush Bugs soon notes that they come in an array of colors. I have read that at least some species can change color, chameleonlike, to match the flowers that they hunt in. I do not know for sure if that is true, but it makes for a good story. The animal in the photo above is nestled in the flowers of boneset, Eupatorium perfoliatum. Boneset, ironweed, and goldenrod are surefire bets for finding these interesting predators. Ambush bugs are very small and easily overlooked. Once one has developed an eye for them, they're easy to see and you might be surprised at how common they are.

I found this little chap to be in an especially showy setting - the flowers of a wonderful little mint known as dittany, Cunila origanoides. I dropped to the ground and spent 10-15 minutes with my camera trained on the ambush bug, hoping some luckless pollinator would fly in and get whacked. It was not to be while I was there, but given the number of tiny bees and flies in the area, I'm sure plenty of meals are scored.

The genus Phymata is not especially large in North America north of Mexico - 20 species or so - and diversity thins out even more east of the Mississippi. Apparently nearly all of the ones in Ohio and vicinity fall into three species: Phymata americana, P. fasciata, and P. pennsylvanica. Separating these species can be quite difficult, especially from photos, so I'm just leaving it at that.

This ambush bug hit the jackpot! It has killed a comparatively massive tachinid (tak-in-id) fly, illustrating the potency of the debilitating neurotoxin that it injects into victims. Not only did the elfin bug quickly KO the larger fly, it then drug it from the flowers and down into the plant, where it was better hidden.

The kill shown here is a great irony; karmic payback? Tachinid flies are parasitoids, laying eggs on hosts such as caterpillars and katydids. The fly egg hatches a tiny grub which quickly bores into the host and commences eating it alive. The fly maggot feeds and grows within its victim, ultimately killing it. This tachinid has met its match in this ferocious little ambush bug.

Keep an eye on the flowers this fall, and I'll guarantee you'll spot a Jagged Ambush Bug sooner or later.

A ruthless killer battles fearsome parasitoids (and will probably lose)

I took this photo almost exactly one year ago - October 9, 2013. It is, or should I say, was the view from my office window. This shot wasn't taken from my window, but when I look down from my nearby office, this is pretty much the viewscape. I really detest vast grassy expanses of turf grass. Such a habitat is pointless, in many cases. Poaceous emerald deserts have their place in parks and other places where people gather outdoors for recreational pursuits. I accept that and have no quarrel with lawns where needed. But the country is overrun with nonnative grass. WAY too much. There is over 40 million acres of the stuff in the United States, which makes grass our biggest crop, supposedly. That's an area the size of Connecticut, Delaware, Kentucky (the Bluegrass State!), New Hampshire, and Rhode Island. Oh, we have to also add Yellowstone National Park to match the turfed over acreage of the lower 48 states.

Stupid.

The attendant loss of biodiversity - the plants and animals that make the world go 'round - is staggering. And most of it is completely and utterly unnecessary.

Here's nearly the same vista as the above photo, shot a few weeks back. I finally put my money where my mouth is insofar as the work complex's landscaping, and convinced the facility managers to install a prairie on the site of the aforementioned grassy wasteland. And bless their hearts, they did it! Many people - maybe most - are interested enough in biodiversity and doing good things for the environment that they will act in Nature's best interest when a chance presents itself. That's what happened here, and the results have been staggering. Keep in mind that the seeds of this prairie were not sown until May 21, of this year.

Major thanks go to Bob Kehres of Ohio Prairie Nursery for providing the seed, and all manner of expertise to help us get our prairie out of the ground.

Needless to say, I've been fascinated with the biological changes resulting from our little one-third acre prairie. At least once or twice a week I take the Canon outside and see what critters I can document. Where one year ago you could count on one hand the few tough animals that would utilize the lawn, it is now a veritable cornucopia of animal life.

The photo above shows a Yellow-collared Scape Moth, Cisseps fulvicollis, plundering nectar from a black-eyed susan. I made this image, and those that follow, this afternoon.

With the now abundant flowering plants providing nectar galore for pollinating insects, the predators have moved in to take advantage of the bounty. This Bold Jumping Spider, Phidippus audax (I think), glares at your narrator from atop a black-eyed susan. No dummy, the spider knows that lurking near a flower will soon produce a meal. It has been amazing to see how quickly the prey-predator food web has developed.

Last week I discovered jagged ambush bugs in the genus Phymata ensconced on the flowers of fleabane. I wrote about these recently, RIGHT HERE. Once again, I was surprised at just how rapidly these interesting insects found and colonized the brand spanking new prairie.

Anyway, sorry for the above deviations into turf grass bashing. It is this ambush bug, which I think may be Phymata fasciata (ID corrections always appreciated!), that I really want to discuss.

I strolled over to check the fleabanes where I had seen the ambush bugs last week, and quickly spotted one who had made a meal out of a tachinid fly. Note the ambush bug's long death-dealing proboscis, firmly injected into the fly's abdomen. The bug will slowly - and with great pleasure, I am sure - suck out the liquefied innards of the fly, leaving behind a desiccated husk.

This is all cool enough, but WAIT! A third insect lurks, to the right of the drama, on the ray flowers of the fleabane. It is truly tiny - so small that I didn't notice it in the field as I fixated on capturing images of the ambush bug. It wasn't until I downloaded the pictures and reviewed them that I saw the six-legged third wheel.

Who is it, and what might it be doing? My first thought was that it is a fly, and was perhaps waiting for an opportunity to drop its eggs on the fly carcass. Maybe its larvae would use that as a host. Those thoughts were quickly dispelled with a closer look - the elfin onlooker is actually a wasp!

This little wasp is too small for even my Canon's 100 mm macro, although I might have done somewhat better had I noticed the thing in the field and took direct aim. Ah well, live and learn.

Now that its identity (I think) has been established as a wasp, it's a bit easier to speculate about what is going on. The world is full of tiny parasitoid wasps that lay their eggs on all manner of insect hosts, and I figured that's what this wasp was scheming to do. A bit of searching around revealed a wasp known as Telenomus phymatae, and I wonder if that's this critter. It is a parasitoid of jagged ambush bugs, but not the adults. It seeks out freshly laid eggs of the ambush bug, and injects its eggs into the ambush bug eggs. The wasp grubs hatch first, within the host eggs, and eat them. So, if the wasp is indeed Telenomus phymatae, it is probably loitering around the ambush bugs awaiting the deposition of some eggs. Ironically, the tachinid fly is also a parasitoid, laying its eggs on some insect victim. What goes around comes around, and we've got a lot of paybacks being dealt out in this photo.

The overarching message of this post is this: plant diversity, especially native plants, spawns extraordinary animal diversity. Even right under our noses, in highly urbanized landscapes, in prairies that were planted only four and a half months ago.

GO NATIVE, and be sure to attend the 2014 Midwest Native Plant Conference.

Pretty but deadly: Flowers of doom

With A Flower

I hide myself within my flower,

That wearing on your breast,

You, unsuspecting, wear me too –

And angels know the rest.

I hide myself within my flower,

That, fading from your vase,

You, unsuspecting, feel for me

Almost a loneliness.

- Emily Dickinson

 

Tis the season of the mighty Asteraceae Family: asters, bonesets, goldenrods, sunflowers, etc. These harbingers of winter brighten the autumn meadows, and many a person remarks on fields painted bright with botanical gold, purple, and cream.

There is a deadly irony in the beauty of these wildflowers, however. Flowers are magnets for insect pollinators, and their presence is part of the charm of flower-watching. But for these nectar-seekers, the danger quotient ratchets up immensely when they alight on flowers. Predators are well aware that sooner or later potential victims will come to visit the flower patch, and they lay patiently in wait.

The robust creamy-white inflorescence of Tall Boneset, Eupatorium altissimum, is quite alluring to all manner of six-legged pollinators. If one of them chooses to work this plant, they had better watch their step. Look carefully and you'll notice three or four tiny bits of dead-looking flower.

Those brownish patches among the boneset flowers are anything but dead plant tissue - they are ambush bugs, a pollinator's worst nightmare. Here we have a Pennsylvania Leatherwing beetle cresting the dome of these flowers, and walking right into a trap. Look carefully: an artfully disguised ambush bug, Phymata pennsylvanica, lays in wait.

This beetle was lucky, or perhaps its size and armoring was just too much for the ambush bug. The latter made a stab at it, quite literally, but the beetle scuttled off intact.

Many bugs are not nearly so fortunate as that leatherwing beetle. I came across this scene two autumns ago. Spotting the little flower wasp from some distance, I stalked in for photos. No stalking was necessary. It had been captured and punctured by an ambush bug! These ferocious hemipterans lunge from the blossoms - an evil flower sprung to life! - and grab their victim with daunting raptorial forelegs. A quick jab with a syringelike proboscis injects chemicals which instantly disable the prey, and dinner is served.

Ambush bugs are common throughout Ohio and the Midwest, and with the exception of the previous wasp photo, I have made all of these images in the last week or so. These fascinating predators are not difficult to find, but obviously are easily overlooked. Their ability to match a flowery substrate is remarkable; the bugs are typically dappled with brown patches to mimic dead plant tissue. This ambush bug, another Phymata pennsylvanica, I believe, illustrates this perfectly as it tees up on a fading Gray Goldenrod, Solidao nemoralis.

Everyone should have a personal favorite ambush bug, and this is mine - the so-called Goldenrod Ambush Bug, Phymata americana (at least I think I am correct on these specific identifications; feel free to correct me if you know better). Goldenrod Ambush Bugs are a buttery yellow, and match the goldenrod flowers to an almost magical degree. An unsuspecting bee, fly, or skipper could be forgiven for not noticing it. The ambush bug will not be forgiving, however, and Dickinson might even have modified her lovely poem had she known that such horrorshows lurk within pretty flowers.

Seen well, an ambush bug is bizarre indeed. They remind me of little gargoyles. Utterly inscrutable, and without emotion. If one of these things was the size of a black bear, we would be in grave danger. Note the huge Popeye-like forelegs, there to seize and immobilize surprised victims.

Here's an ambush bug, prodded out of cover for our viewing pleasure. A more remarkable insect is hard to imagine. Next time you are among a goldenrod patch, or other plants that produce dense masses of blooms, investigate carefully for these beasts. I'm sure you'll find some.