If you haven’t heard, a recent article reports that crayfish (superfamily Astacoidea) experience stress and anxiety similarly to humans. The neurotransmitter that triggers an anxious emotional state in humans is also found in the brains of crayfish that exhibit anxious behavior (i.e. hiding), and the same drug used to treat human anxiety also caused crayfishes to become more exploratory (i.e., hide less).
Ohio is home to 21 species of crayfish. In addition to being used for bait, crayfish are also eaten by humans. Once considered a “poor man’s food”, crayfish are now served in upscale restaurants, depending on the season and your locality. They are primarily an aquatic animal but some species create burrows to access muddy terrestrial habitats. These burrows look like “mini volcanoes” and can be easily seen at Wahkeena Nature Preserve along the trail sections that pass close by the pond. Crayfish are more active at night, but may be found hiding under logs and rocks in ponds and streams during the day.
The thought of arthropod anxiety intrigued me, so I trawled the internet and discovered Gourmet Magazine’s Consider the Lobster, a hefty article describing not only the lobster’s role in our economy and how it’s been perceived through the ages, but also its physiology and ecology. This topical quote is on page 5:
This author posits that the lobster is capable of perceiving something akin to pain, or at the very least a strong preference to not be in boiling water. Boiling alive an organism that can exhibit a preference raises some interesting ethical questions.
Some argue that things lacking an internal skeleton are too primitive to possess the neurological hardware required to feel pain, much less anxiety, but the crayfish study might bring some pause to that argument. Moreover, labeling organisms with value-laden terms like “primitive” (=not evolved) or “advanced” (=evolved) is erroneous, or misleading at best.
Take, for example, the humble horseshoe crab. These ridiculously adorable arthropods are not a crab but a chelicerate, sharing a common ancestor with today’s spiders and scorpions.
Often touted as a “living fossil”, we may never know if their ancestors had similar physiologies, but their body plan has endured 445 million years and five mass extinctions with relatively little change. That’s almost half a billion years, about 10% of Earth’s history, or nearly 50% of the history of multicellular life!
Their degree of relatedness is contested but it’s fairly certain that trilobites and horseshoe crabs were close cousins. Although horseshoe crab fossils are not as numerous and not quite as old, they overlap with the trilobites by one or two hundred million years, so it’s possible that they trundled alongside each other in the same shallow seas.
The trilobites were the most numerous and diverse life form on Earth throughout most of the Paleozoic era. Trilobite species numbered in the several tens of thousands, ranged in size from 1 millimeter to over a meter long, and some possessed improbably ornate and complex spines, antennae and prominences. How cool would it be to see one of these fascinating animals alive? But despite their incredible diversity and persistence over 300 million years of geologic time, after a slow decline in diversity and abundance in the fossil record they finally went extinct (along with over 95% of all other sea life) during the Permian-Triassic extinction 251 million years ago.
But the horseshoe crab did not. Trees evolved and colonized the land; mountain ranges rose and eroded into dust; whole orders of animals evolved and died out; temperatures soared and plummeted; glaciers repeatedly scoured the land; continents separated and collided and separated again, and not long ago human ancestors walked upright; but the horseshoe crab remained. The ancestral characteristics it’s retained have made it one of the most enduring and successful life forms to have ever lived. Perhaps we need only look at the horseshoe crab to get a glimpse into trilobite life.
Today, there are only four species of horseshoe crab in existence. In the United States the Atlantic Horseshoe Crab (Limulus polyphemus) is used in biomedical research. The horseshoe crab does not have an immune system like ours; its blue blood coagulates when it encounters endotoxins released by foreign bodies, thus trapping invasive organisms inside a clot. This clotting property makes it very valuable for testing vaccines and medicines for bacterial contamination. Once nearly decimated for fertilizer and fish bait, the horseshoe crab is now worth much more alive than dead. A single liter of copper-based horseshoe crab blood is valued at $15,000 a quart.
Although the blood collection is touted as non-lethal, one study indicates that up to 18% of crabs die after having their blood drawn. The blood drawing also appears to impair female mobility and feeding rates, which affects their reproductive output; this in turn may contribute to recent population declines. The Atlantic Horseshoe Crab (Limulus polyphemus) is listed as “near threatened” on the IUCN Red List.
Humans are not the only animals that benefit from horseshoe crabs. Their eggs are a vital source of fat and protein for many shorebird species, such as the Red Knot, which time their spring migration to match the seasonal egg-laying of these arthropods. A Red Knot’s migration can be up to an 18,000 mile round trip! Without this food source, the shorebirds can run out of energy and die without reaching their breeding grounds. Because of this, the North American subspecies of Red Knot has been proposed for “threatened” status under the Endangered Species Act.
The unassuming horseshoe crab, despite its inoffensive habits, retiring nature, and relatively low populations, nevertheless has a disproportionately large impact on the ecosystem. I wonder how the loss of the trilobite influenced how our biome functions today.
Arthropods like the crayfish and horseshoe crab went down a vastly different evolutionary path than ours. Our common ancestor lived over 600 million years ago—so long ago that we’re not really sure what it looked like or how it lived. One side effect of this evolutionary happenstance is that we have a different number of limbs—probably the main reason why many people find them unsavory or even detestable—the crime of having “too many legs”.
But evolution does not find the best solution to a problem; it finds one solution. Completely independently of each other, chordates and arthropods both developed supportive tissue (i.e. skeletons), complex eyes, sophisticated sensory systems, intricate social behaviors and even flight; yet arthropods make up over 80% of all animal species. Chordates like us make up only 3-5%. Are arthropods primitive? You tell me.
They may not be composing symphonies or doing your taxes, but they might be feeling a little nervous when you walk by.
Did you know the Ohio History Connection has a large collection of natural history specimens? In fact, you can explore the natural heritage of Ohio from the state’s ancient bedrock, to its Paleozoic marine fossils, to the state’s modern flora and fauna, all at the Ohio History Center. Who knew?
Well, we did.
And we want you to know, too – that’s why we’re hosting a Twitter takeover with Natural History curators, David Dyer and Erin Cashion!
On Wednesday, September 24, between 11am and 2pm EST, Dave and Erin will take over the @OhioHistory Twitter feed to answer your natural history questions in 140 characters or less.
Why in 140-characters or less? Twitter is a social network that not only encourages, but demands brevity and information-sharing in 140-character messages called tweets. Dave and Erin assure us that they are up to the challenge.
They will share interesting and fun facts about our natural history collections, answer your questions about our new exhibit Going, Going, Gone? Endangered and Extinct Species, as well as sharing details about their day-to-day work. Have you ever asked yourself, “What does a curator do, anyway?” Here’s your chance!
So tune in tomorrow and tweet us your natural history questions at @OhioHistory and use the hashtag #GGGone!
By Bob Glotzhober, Curator Emeritus, Natural History
On June 27th this year I posted a blog about searching for Timber Rattlesnakes with Doug Wynn. I have been blessed to get into the field two more times with Doug, and each has been a memorable experience. Last week our trip was memorable in a variety of ways – not all of them pleasant.
Earlier this year Doug received a pregnant female rattlesnake that was found along a service road in Shawnee State Forest. Such live snakes are presented to Doug from time to time by people who are familiar with his research and conservation efforts. When this happens, Doug surgically implants a radio transmitter. Afterwards, he holds the snake for about five days, administering antibiotics to make certain the snake is healthy before releasing it. Next, he goes as close as possible to where it was found and releases it. The idea, of course, is to follow it from time to time during the summer to see how far it travels, what habitat it uses, and anything else that can be determined about its natural history.
Since this snake was pregnant, it was of special interest to find out where it went to give birth. I joined Doug on July 24th and we climbed all over the hills of Shawnee. The signal from the female’s transmitter kept going strong, then weak. Doug told me that sometimes signals will bounce off of hillsides in a valley between the hills, or a ledge or trees might obstruct, temporarily conceal or bounce the signal so that it appears to be coming from a different location. Usually, however, with time, those false signals can be worked out as you cover more ground and get signal directions from multiple locations. After several hours on July 24th – we had to give up. Doug had a commitment for an afternoon demonstration of implanting a transmitter in another snake and did not want to be late.
I traveled down to Shawnee State Forest and joined Doug and his good friend and former co-teacher John Birkhimer on September 9th. They had made another effort the day before at finding the elusive pregnant female rattler. That day had become the fourth failed, fatiguing effort at pinpointing the female. This day, the three of us would try one more time to find the female. The good news was, they had furthered narrowed the search and had a plan of attack. We would park further down the road and head up to the top of a winding ridge line. Following this ridge, we anticipated locating the female a little over the edge near the top of a ten-year-old clear cut.
While the terrain seemed like it would be a fairly easy hike, the ridge top proved to be a dense tangle of greenbrier. If we dropped down to our left, we would lose the telemetry signal behind the hill. If we dropped down to our right, we’d enter an even denser tangle of the clear cut. The only reasonable path was to stay on the ridge top. Reasonable? That becomes a relative term. Greenbrier has quarter-inch long, straight thorns that tear at both clothing and skin. Their evergreen, twining stems enable the plant to climb and cling to other vegetation and create tangles that are hard to penetrate – unless you are Brer Rabbit! In some places we could carefully step on the thorny branches and push them out of our way with our boots. In other places they twisted high above our heads and we had to try to push them aside and crawl between them. It was not long before each of us had bloody arms.
The good news was, we still had signals from the transmitter inside the female rattler and those signals seemed to be getting stronger. After nearly three hours of bush-wacking we realized we had actually passed by the source of the signal. It was time to retrace our steps and work more slowly and carefully. About 100 yards back, the signal seemed to be just down the hill from us. A later study of the maps would show that in three hours we had covered only about three-quarters of a mile but it had felt like ten!
We slowly started down the hillside, and as we did the signal became even stronger. We were very close. Then the signal got a little weaker. Was the snake on the other side of a large oak in front of us? No, but perhaps the oak was partially blocking the signal. Then we spotted an old, rotting, cut-off stump nearby. No sign of the snake on or behind that stump. We stood by the stump for a moment, distracted by an interesting large, reddish wasp. [See an upcoming blog on this wasp and its unusual behavior.] Then Doug noticed that the signal was weaker in most directions—but if he held the receiver directly above the rotten stump, it was much, much stronger. The snake had to be inside the rotten stump which we were now surrounding!
The stump had a hole on the downhill side, but we could see nothing inside that hole. There was another, large hole on the top of the stump, going down into its interior. Inside this hole, perhaps down eight inches or so, sat four ten or twelve-inch long baby Timber Rattlesnakes. As we watched, one of them crawled deeper still, joining a fifth baby another six inches deeper into the rotten core of the stump.
As we watched, Doug noted that two of the five babies had molted. Three were sort of a muted, reddish brown color, but the other two had the bright and bold markings of an adult – in a pattern of gray, white, black and brown. Doug explained to us that newborn Timber Rattlesnakes make their first molt when about five days old. We were looking at five-day-old baby snakes, which most likely were given birth inside this hollow stump. Rattlesnakes, by the way, are what is known as ovoviviparous – which means they carry the baby snakes inside soft egg sacks inside their body, then give live birth.
What a fantastic finding! To say we were thrilled is to put it mildly. Five days of hard hiking and searching (only two for me) had finally paid off with a valuable observation. We never did see the female, but she must have been deeper yet within the stump based upon the signals from her transmitter. We spent perhaps half an hour watching the snakes (and the wasp) and trying to get photos of them. Photography was challenging – trying to get autofocus or even manual focus to work eight inches down into the dark cavity of the stump. Not to mention not wanting to brace our arms on the stump to steady our cameras. Meanwhile, we wondered if the large female might at some point emerge to defend her babies. She never did.
The hike back out was somewhat easier – being mostly downhill and following a path we had already partially cleared. But greenbrier tends to spring back quickly and we still struggled to avoid its thorns. Over the two days, John had developed bad blisters on the heel of one foot, which grinded painfully as he stepped downhill. We all were caught more thorns. Somewhere mixed in with the greenbrier was some poison ivy. I managed to spot some of it, and avoid it – but obviously there was more that I got into while dodging the greenbrier. The next day, both my arms were covered with poison ivy blisters, which took almost two weeks to heal.
Would I repeat the experience with more bleeding from greenbrier and scratching from poison ivy? You bet! In fact, I’ve been contemplating what I could have done to use my tripod to steady the camera – just in case a similar situation presents itself someday. Rattlesnakes, greenbrier, and steep forested hills are all part of the allure of the wild area known as Shawnee State Forest – a real Ohio treasure.
By the way, you will not find the name Greenbrier Ridge on any maps. To protect the snakes, we would not report a precise location. But we all agreed that this particular ridge should have that name, and we will probably use that nomenclature in future discussions, loaded with interesting memories.
By Bob Glotzhober, Curator Emeritus of Natural History
In the exhibit we feature Rachael Carson, and talk about how she warned the world about the dangers of indiscriminate use of the insecticide DDT. Her landmark book “Silent Spring” was published in 1962; so why was Ed Thomas mentioning DDT 14 years earlier!? What did he know that wasn’t to be common knowledge for over a decade later? Here are some quotes from his article:
“Applied to window and door screens or to the inside walls of stables, DDT is little short of miraculous in exterminating flies and mosquitoes….But – and note this carefully – neither DDT nor any other insecticide is selective. It destroys good and bad alike and it fails to affect certain dangerous insects. ““Here is a homely example: I have been dusting our roses with a “shot-gun” rose dust. Among a number of other things, it contains DDT. DDT is moderately effective against rose aphids, but it is horribly lethal to some of the aphid’s enemies, such as syrphus flies and many near-microscopic wasp-like parasites which feed solely on aphids. Result: the dust has not controlled the aphids on my roses. Aphids on other plants in my garden seem more numerous than usual….I am seriously debating whether I should use DDT on roses.”
“DDT has another serious drawback. It is extremely lethal to fishes, frogs and salamanders and aquatic insects. I must warn against using it in ponds to destroy mosquito larvae unless you are willing also to destroy every other living thing in the pond.”
“I am especially concerned over a new type of spraying equipment, known as a ‘mist sprayer’, which is capable of spraying tons of DDT or other potent insecticides at high velocity through dense woodland. If used indiscriminately its capacity for harm is limitless.”
“The new insecticides are proving invaluable in combating many specific pests which have previously been difficult to control. But let’s use them sparingly, cautiously, and as intelligently as possible. If we don’t, they’re likely to boomerang – with a bang.”
Not only does he warn us about DDT, 24 years before it was officially banned in 1972, but this article illustrates the value of natural history – of close observation of the natural world. Ed Thomas noted the problem with DDT, and the complexity and interactivity of all species, just by carefully observing the insect populations on his rose bushes.
Otoliths from the Freshwater Drum can be found on beaches today, especially along the shores of Lake Erie. They are called “lucky stones” by some beachcombers. A sulcus, or groove, is on one surface of the otolith and appears as the letter L on the stone from the fish’s right side and the letter J from the left side.What a cool fish! Not only does the Freshwater Drum have weird ear stones but it has unusual teeth! You might remember that we featured the pharyngeal teeth of the Drum in a previous blog post, and linked to Juli Six’s blog in Archaeology where she discusses these teeth. Click here to read the blog.
Dave Dyer and I will be fielding all your Natural History questions from 3-5PM here at the Ohio History Connection. Log in to Twitter and follow @OhioHistory, or find the Ohio History Connection on Facebook and follow the hashtag #AskACurator.
We love talking about our collections and answering questions about the natural world. My field of expertise is birds and reptiles, amphibians, and terrestrial arthropods. Dave specializes in mammals, bones, and fossils.
Ask away! It’s the next best thing to visiting us at the History Center.
By now you’ve probably heard that the Carolina Wolf Spider (Hogna carolinensis), not found in Ohio since 1963, was re-discovered in Adams County a few weeks ago.
I first heard about it from a coworker, who said the photo accompanying the article depicted something tarantula-like. His perception was that of a frighteningly large and possibly angry spider. His vivid description led me to assume that the wrong picture had been used for the article—there are no spiders even remotely approaching tarantula size in Ohio!
Once I had a chance to read the article, I could see that this certainly was not a picture of a tarantula, and if anything it seems more befuddled than antagonistic. Whatever the species, it is indeed quite an arresting arthropod. What gorgeous flame orange chelicerae!
One might more readily believe this lovely animal to be some manner of tropical denizen rather than a native Ohioan, but my initial assumption turned out to be quite false. The photo is not only the correct species, but also THE individual discovered in Adams County! The cord-like device plumbing the depths of his burrow is a borescope, a flexible tube with a light and a camera on the end. Without this invaluable tool the spider may not have been rediscovered at all! The Carolina Wolf Spider’s leg span may approach 3 to 4 inches, making it the largest wolf spider species in North America.
Wolf spiders (Lycosidae) are a family of ground-dwelling arachnids that actively stalk and pursue their insect prey, hence their name.
Like most spiders they have eight eyes, but four are especially well-developed. They are capable of great bursts of speed, but climb poorly. As fall approaches wolf spiders can sometimes be found taking shelter in homes and garages, where they hunt down the insect pests in your house. So if you see a fairly large spider scurrying across your floor, don’t worry! Wolf spiders are reluctant to bite and their venom is not dangerous to humans, so with gentle handling they can be safely relocated outside, if desired.
It’s unlikely that you’ll find a Carolina Wolf Spider in your house anytime soon, however. The species was re-discovered in remnant prairie habitat within the Edge of Appalachia Preserve system in Southwest Ohio. According to the US Forest Service, less than 0.01% of Ohio’s original prairie habitat remains. Prairies support an immense number of rare plant and animal species, from orchids to butterflies to bobolinks to bison, so protecting prairie habitat has an “umbrella” effect. Prairies are vastly underappreciated, yet they provide incalculable ecological services—chief among them, the prevention of soil erosion and evaporative water loss. Unfortunately, almost all of North America’s remnant prairie has been converted to agriculture, and untold volumes of topsoil have been lost as a result. Indeed, the Nature Conservancy states that prairies and grasslands are the world’s most imperiled ecosystem.
While greatly reduced in acreage from its former splendor, it is encouraging that Ohio’s prairies are still hale enough to support the return of this important predator.
In closing, I’ll share one more thought. While researching this blog post, I discovered that the above photo above had been cropped. Here is the original:
I wonder if my co-worker would have perceived the spider in quite the same way if he’d seen this photo instead.
Now that you’ve seen it, did your perception of the spider change? Let us know in the comments!
Jim McCormac of ODNR is one of the three naturalists who re-discovered this impressive arachnid. I highly recommend that you read Mr. McCormac’s full account of the encounter here.
This coming Saturday, September 13th, Bob Glotzhober, Curator Emeritus of Natural History, will be presenting his popular talk “Those Magnificent Monsters of the Ice Age.” It will be free to the public, at the Hurt/Battelle Memorial Library at 270 Lilly Chapel Road, West Jefferson, Ohio at 10:30 a.m. He will certainly talk about the “monsters” that fascinate so many people, but he’ll spend more time with some of the lesser known extinct animals like the Giant Beaver and the Stag-moose. A skeleton of the Stag-moose was excavated by three OHC staff near Medina in 2008 – and it has some huge tooth marks on the bones. Bob and Dr. Greg McDonald are still trying to build sufficient evidence for the predator that they think ate (and perhaps killed) this 1,000 pound relative of the modern moose – and Bob will share their evidence to date for this theory. Bob will end the talk with a discussion on theories as to why these “mega-fauna” disappeared at the close of the Ice Age. Should be fun – come join us!