Stop This Meme

Here at Bug Eric, I have better things to do with my time than constantly fight wave after wave of misinformation, superstition, and outright hoaxes. The latest is this one purporting that a "new" and "deadly" spider has invaded North America. Utter nonsense!

The spider depicted in the images is the very much harmless Woodlouse Hunter, Dysdera crocata. This spider is originally from the Mediterranean region of Europe, but made its way to North America ages ago, not recently. Yes, it has wicked-looking jaws and fangs, which are used solely to turn over its roly-poly and sowbug prey so that it can inflict a lethal bite on its food, not on human beings. The venom of this spider has not been scientifically proven to be the least bit dangerous to the average, healthy person.

"But, but...." you say, citing the watermark on one of the images in the meme as being from the University of Nebraska. Surely we can trust our institutes of higher learning, right? Yes, but not if their image has been stolen by some malicious individual out for hits on his or her own website. The university should consider filing suit against whoever is using this image. There are laws against copyright infringement, which is what is happening here. The Digital Millennium Copyright Act (DMCA) exists to protect our "works" from unscrupulous individuals who seek to profit from our efforts at education and enlightenment.

By sharing this meme, and others like it, without doing due diligence of fact-checking (a quick check on Snopes would have yielded the truth about this one), serves only to perpetuate ignorance at best, and participate in crimes of "fake news" and, in this case, copyright violation. Stop it.

© Jenn Rose #jennrosefx

Pseudoscorpions: The Strangest Arachnids?

Yes, the image below is of a crane fly in the family Limoniidae, but what is that other thing attached to it? The crane fly showed up at our backyard blacklight a few nights ago in Colorado Springs, and by itself would have been interesting. Its hitchhiking companion made it even more spectacular.

Crane fly with pseudoscorpion gripping its leg

Pseudoscorpions are tiny arachnids, most of them under five millimeters in length, that never fail to provoke head-scratching among people unfamiliar with them. They look like they could be baby scorpions that are missing their telson ("tail"), but they are literally in an order unto themselves: Pseudoscorpiones. They are fairly common, but seldom seen because they frequent microhabitats under bark on trees, stumps, and logs, or leaf litter or topsoil, or in mammal nests or caves, or other places that require a dedicated effort to uncover them. It is only those species that occasionally turn up in our "caves" (homes) that catch our attention.

I wrote about pseudoscorpions previously, for Missouri Conservationist magazine, thanks to fantastic photographs by Ashley Bradford and Ted MacRae, but this week's find finally allowed me my own imaging opportunities. It is interesting that the insects favored as transportation by pseudoscorpions are frequently those associated with decaying wood: longhorned wood-boring beetles (Cerambycidae), braconid wasps that are parasites of wood-boring beetles, and in this case a female crane fly which I would bet oviposits (lays eggs) in decaying wood.

Pseudoscorpions are predatory on other small invertebrates such as springtails, barklice, fly larvae, and mites. They seize their prey with the pincer-like chelae at the ends of their "arms." Those heavy, muscular appendages are actually modified mouthparts called pedipalps. Many species of pseudoscorpions have venom glands in the chelae that help subdue struggling victims. From there, the prey is passed to the plier-like chelicerae, or jaws, that puncture the body wall of the prey, or crush it, and allow for the introduction of regurgitated enzymes to begin the extraoral digestive process. The resulting liquified material is then ingested by the pseudoscorpion.

Bizarre? We are just getting started. The chelicerae also house silk glands, and pseudoscorpions spin silk to encase clutches of eggs, for shelter during molting and overwintering, or even as a retreat from which they can wait in ambush for unsuspecting prey to pass within reach.

Using another animal for transportation is a behavior called phoresy, and that appears to be the chief means of dispersal for pseudoscorpions. They do not have wings, after all, and are so tiny that getting from one optimal niche to another under their own power is almost impossible. Also, they do not "balloon" as many spiders do, spinning silken threads that are caught by the wind and waft the spider to a new home.

After the crane fly died, the pseudoscorpion disembarked and I was able to get the images you see here. I discovered they are much more agile than I anticipated. This one could scuttle backwards fairly rapidly, run forward quickly, and it could easily climb the slick walls of our casserole dish "studio." Maneuvering the tiny creature with an artist's paintbrush was challenging since the animal could simply grip a single bristle and refuse to let go.

The social life and love life of pseudoscorpions is surprisingly complicated. Members of some species can live side by side without antagonizing each other, displaying unique and rhythmic movements of their bodies and/or pedipalps to communicate. Meanwhile, courtship between male and female in nearly all species is accomplished through a variety of behaviors. In all cases, the male packages his sperm in a spermatophore. In the most primitive scenario, he simply deposits on the ground or other substrate where he hopes a female encounters it. She will then pick up the spermatophore in her genital opening.

Males of other pseudoscorpion species will only deposit a spermatophore if they encounter a female. These males may then spin a simple or elaborate, three-dimensional silken bower to help funnel the female to the location of the spermatophore. This greatly improves the male's chances of reproductive success.

Mating can be more intimate in the most "advanced" species. This involves what is best described as dancing, the male grasping the female's pedipalps in his, and gently but firmly guiding her over the spermatophore he has just deposited. There may be subtle choreography and pre-programmed body movements involved in that. They may even kiss, if you will, interlocking their chelicerae.

Pseudoscorpion from leaf litter in Massachusetts

Despite the extent of our collective knowledge of pseudoscorpions, new species are discovered with a surprising degree of regularity. Those who study caves and other specialized habitats; and those who study rodents and other vertebrates, would be wise to keep their eyes out for pseudoscorpions. Meanwhile, carefully inspect the insects at your porch light and you might eventually find one of these arachnids on an insect attracted by your beacon.

Sources: Johnson, Elizabeth A., and Kefyn M. Catley. 2002. Life in the Leaf Litter. New York: American Museum of Natural History. 28 pp.
Weygoldt, Peter. 1969. The Biology of Pseudoscorpions. Cambridge, Massachusetts: Harvard University Press. 145 pp.

Wasp-watching

It has been difficult to build-up enthusiasm this summer because insect abundance is way down here in Colorado Springs, but when I get to witness an event like I did yesterday, it makes me glad I went out and made an effort.

Female Ammophila sp. with heavy load

I happened to glimpse a very odd, fairly large insect out of the corner of my eye. It took me a minute to realize it was not a single insect, but two: a female Ammophila sp. thread-waisted wasp toting a caterpillar she had paralyzed. She was trying to locate the concealed nest burrow she had excavated before going hunting, and was wandering around rather aimlessly, but at high speed.

At one point she cached the caterpillar so she could orient herself without such a burden. It worked. She found her burrow, then went back and got the caterpillar. I was lucky to get any images of the transport because she moved so speedily and kept going in and out of focus. Even an attempt at video may have been almost useless. Her agility, with such a heavy load, was impressive. It would be like you or me running at full speed carrying a sofa between our legs.

Removing the "door" to her burrow

She abruptly dropped the caterpillar, and in a matter of seconds uncorked the stone plugging her nest burrow. She quickly entered her burrow, turned around inside, and re-emerged to grab the caterpillar and pull it in. She has to be this fast to avoid tiny parasites known as "satellite flies" that will lay tiny maggots on the caterpillar before the wasp can get it secured underground. Indeed, there was at least one miltogrammine fly flitting at the entrance to the burrow.

Pulling the caterpillar into her burrow

About a minute or so passed with both the wasp and her caterpillar underground. Finally, she emerged topside and quickly retrieved the stone that had plugged the burrow opening previously. She replaced the stone and began kicking sand on top of it. Notice how she curls her front "feet" to maximize the tarsal rake of spines that aid her in digging and filling. At one point she was startled by a curious ant and took to the air for a spit second. Ants can raid wasp burrows and cart off the caterpillar and wasp egg as food for their own young back at the colony.

Replacing the "door" to her burrow

By now I was getting a bit stiff from having stood in the same place for a long while. When I left the wasp, she was apparently unsatisfied with the nest closure and was actively chewing down to the rock plug. I left her in peace to finish what she had started.

Kicking sand to conceal the entrance

The whole sequence of events involved in the provisioning of a nest by a solitary wasp is truly remarkable. She has to dig her burrow and, load after load, flies off with armfuls of soil to fling across the landscape, lest some predator or parasite recognize her nest from piles of "tumulous" around the opening. Next, she fills in the burrow entrance, obliterating all evidence of any cavity whatsoever. She may make a brief orientation flight and then go off to hunt. How does she ever find the burrow again? We cannot even remember where we parked our car, or left our cell phone, and we reportedly have much larger brains than wasps do.

Startled by an ant

Once she has completed her mission of providing one paralyzed caterpillar for a single offspring, she goes off to start the process all over again, somewhere else. Does the wasp immediately forget about the burrow she just completed? How does that instinct work? It has to be plastic enough to address unique situations and overcome obstacles.

Up and away for good?

Over the coming months, in that underground cell, a wasp larva will hatch from the egg and begin consuming its still-living but inactive larder. Scientists believe that insects have no pain receptors, so that must be a blessing to the caterpillar. Were it deceased, though, the caterpillar would quickly rot under the assault of bacteria and fungi. After consuming the caterpillar, the wasp larva enters the pupa stage, as equally inert as the caterpillar on the outside, but inside the pupa there is a massive reorganization of cells converting the grub-like larva in to a sleek, winged adult wasp. Some genes are turned on, others are turned off. It is amazing to contemplate that a wasp larva, or caterpillar, has inside it the latent ability to execute all the behaviors of the adult. It somehow "knows" it cannot fly, does not need flower nectar, and cannot reproduce as a larva. It understands at some fundamental level that its only job is to eat and grow.

Some finishing touches

The next time you are out hiking, and a wasp flies up from under your feet, stop for a second. Back up a little. Does the wasp return to the vicinity? If so, keep watching. She is probably in the process of working on a nest burrow and will resume her activities if you stand still. It takes a little practice just to think about this possibility, but the rewards can be astonishing.

I Value Your Comments, But Am Not Getting Notifications

I have not been receiving e-mail notifications of comments on this blog as I used to, but thanks to a prompt from one of you I discovered I had a whole backlog of comments awaiting my moderation. Some of those dated back to September of last year! I will try and get the notifications generated again, but in the meantime I will look in on pending comments at least weekly. You have my sincerest apologies for this oversight. Thank you.

Why do I bother screening comments? My posts would be "spam city" if I did not, and I know you don't want unsolicited advertisements for Viagra and such, abusive language, and other nonsense.