Remarkable Mimicry: Fly as Wasp

 

A huge - compared to other common wasps, but maybe not an elephant - spider wasp, Entypus unifasciatus, takes nectar from the flowers of a Rattlesnake-master, Eryngium yuccifolium.

ASIDE: Rattlesnake-master lures pollinating insects like few other plants. And it is quite showy with numerous ball-like inflorescences of snowy-white flowers and its odd leathery yucca-like foliage. It grows easily in gardens and is a fantastic addition to anyone's yard. And Rattlesnake-master is readily available in the nursery trade, at least among nurseries that make an effort to peddle native flora.

I spent a fair bit of time at Chaparral Prairie State Nature Preserve on August 5, which was at its peak of botanical glory. See some photos of the prairie RIGHT HERE. The Rattlesnake-master was in nice condition, and I probably could have spent all day stalking and shooting the myriad pollinating insects visiting its flowers. As it was, I did manage to photograph a number of them, perhaps highlighted by this huge wasp.

Entypus unifasciatus is one of the spider-hunting wasps and is impressive by any hymenopteran standard. It is an edgy beast, active and constantly twitching its wings with rapid flicks. This species specializes on large wolf spiders (female wasps do the hunting and stinging), and an insect has to be tough to take one of these venomous eight-legged behemoths down. I have seen the wasp vanquish spiders a few times, such as HERE, and HERE.

From my limited experience, the spider is no match for the wasp. The latter darts in and administers a punishing, paralyzing sting in the blink of an eye. The wasp's venom must be a potent brew indeed, and I suspect its sting would pack a punch to a person, too. Fortunately, they are not aggressive and short of grabbing one with your hand, it'd probably be nearly impossible to get stung. However, inquisitive birds might have to learn this lesson the hard way. Except for Summer Tanagers, which specialize in capturing and eating large bees and wasps.

Well, what do we have here? I made this image in the same area as the preceding spider wasp, on the same day. And, while completely unrelated, this insect bears a remarkable resemblance to the large stinging wasp. It is just as big, too.

This is a mydas fly, Mydas tibialis, which is completely impotent as far as having any ability to inflict pain. The big fly is visually intimidating though, and most people - and more importantly birds, presumably - would leave it be. The fly even nectars at the same flowers favored by the wasp.

The fly world is awash in amazing mimicry such as this. Flies that can mimic the appearance of bees and wasps that can inflict stings must gain some measure of protection from visual predators like birds, who will learn to avoid certain insects such as those whose appearance they mimic.

Mydas fly

I don't mean to be too heavy on the flies of late, but this one is just too cool not to plug. Besides, I've seen a few of these gnarly jumbos lately, and it may be a good year for them, for whatever reasons. If you see one of these giants, I guarantee you'll notice it.

BIG bug, on the corner of the headstone

I'm on the board of Columbus' Green Lawn Cemetery, which is one of Ohio's oldest (founded 1848) and second largest (360 acres). We manage it as an arboretum and park, which is how I came to be one of the board members. Some of the state's oldest and largest trees can be found, and about 90% of the native trees in Ohio are present. We've planted a three acre prairie, and there is a lush butterfly garden. Quite the urban oasis, a legendary birding locale, and teeming with all manner of wildlife.

I was in Green Lawn today, helping our general manager, Linda Burkey, give a tour to Patty Toneff of Toledo's Woodlawn Cemetery (another famous birding spot). We were slowly cruising along on one of the cemetery's 25 miles of roads when I saw a VERY large insect make a brief flight and come to rest at the base of a headstone. Fortunately, the women were tolerant enough to allow me a moment to leap out, grab the Nikon, and make some images.

Well, out I shot, camera in hand. The insect was not overly intimidated and allowed me to creep ever closer. I knew it was - or at least was fairly certain - some kind of fly, but the others that I had seen in the past week did not cooperate and no photos were made. So, I hadn't yet pinned a name on the beast. It acted rather territorial, flying to a few favored perches and acting as if it were guarding this particular piece of turf. It turns out that it probably was.

It was easy to make the identification once I returned to resources: mydas fly, Mydas clavatus, and it is indeed a robber fly looking thing. These animals are really big, comparable to our largest wasps. And indeed, it is a wasp mimic, trying to look like the big wasps in the Pompilidae family, and it resembles some of those species to an eerie degree. They even dangle their legs in flight, like wasps do.

So, as with the bumblee mimic robber fly that I recently posted about, this mimicry begs the question WHY? It turns out that in this case, the fly probably looks just like one of the large heavyweight stinging toughs so that other predators leave it alone. Tangle with a giant insect that packs a heckuva sting once or twice, and any bug-eating predator may learn to give them a wide berth. Presumably the mydas fly cashes in on this wasp world respect with its charade, and everyone leaves it alone as well. Except, probably, Summer Tanagers which dearly love huge ferocious bees and wasps and probably snap these mimics up as well.

Apparently adults will establish favored territories which they guard from other mydas flies, and that's what the one in these photos seemed to be doing. Interestingly, adult mydas flies are not thought to be predacious as are nearly all of their robber fly lookalikes. Instead, the adults seek nectar at flowers. The larvae are not pacifists though, and snack on beetle grubs in the soil or rotting wood.