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.

Spider wasp in action

Along with Rick Gardner and Ray Showman, I had one of the best botanical field trips of the year today. Mind you, this was not a trip for the faint of heart, in part because sedges - oh no! sedges and tigers and bears, oh my! - were a primary target. But both Rick and I are died in the wool caricophiles (sedge nuts), and Rick had discovered a veritable Eden for those of our ilk.

So off we went, on what must have been the hottest day of the summer to date. And the place that we went, in Gallia County in SE Ohio, was just about as far off the track as one can get in the Buckeye State. We parked on a seldom-traveled gravel country lane, and hoofed about a mile and a half back into serious floodplain swamp country, traversing several steep ridges in the process.

It was worth it, and I'll put up some of the spectacular plants that we saw later. But, as always there were other distractions, and in keeping with yesterday's theme of terrifying killers of the insect world, I want to share a very cool experience that we bore witness to, from start to finish.


As we were passing along the side of a steep ridge, I noticed one of the big showy spider wasps working an area of downed branches and accumulated leaf litter. I pointed it out to Rick, and commented that it was actively hunting wolf spiders. We stopped to watch for a bit, when the wasp suddenly dove into some leaves, and in what seemed like a few seconds, tossed out a large wolf spider, having apparently stung the victim in the blink of an eye. In no time flat the wasp had drug the already dopey spider several feet from the site of the initial encounter.



The video above was made immediately after the wasp scored the spider.

I believe this wasp is Entypus unifasciatus, one of the larger and showier of the parasitoid wasps. They are comspicuous, as they continually flick their wings and spread their antennae, both of which are boldly marked with yellow. Just speculation, but I suspect this wing-flicking antenna-waving act creates visual jolts which help to startle potential victims into movement, and thus make it more likely that the wasp will spot them.

If you look closely - click on the photo to expand it - you can see the poor spider's eyes peering out. It is doomed, and the end will not be pleasant. The wasp injected it with neurotoxins which cause paralysis, but the spider is very much alive. It is being dragged to a burrow that the wasp has pre-selected for interment.

This was far too good an opportunity to let go, so we carefully followed the wasp as she tugged her victim along. I figured the burrow would be very near at hand. It wasn't. We tracked the wasp for approximately 130 feet, and this hard-working insect rapidly tugged its prey over branches, sticks, leaves and all manner of obstructions. Every now and then, she would stop and essentially wander about a small radius from the spider, presumably picking up a pheremone trail or some other clue to ensure that she was going in the right direction.

It took her almost exactly 15 minutes to cover the 130 feet from kill site to burrow, and the route that she took was remarkably straight. We were impressed. The spider is as big as the wasp, and presumably equal to in weight if not heavier. A truly herculean feat, moving it as far and as rapidly as she did.

Finally, the wasp reached this small hole and wasted no time pulling the spider in. She was in there when I took this photo. Although we can't see it, she is laying an egg on the paralyzed spider, then probably sealing it in with soil. Eventually, that egg will hatch, and the grub will have fresh meat, eating the living spider. All goes well, and ultimately another big beautiful black and yellow wasp will emerge from the spider's grave and start the process again.

A video showing the general lay of the land. Nice bit of luck for us, and the wasp, but certainly not the spider.