Tarantulas

Beginning in late June, the prevailing winds in the American Southwest change directions. Warm, moist tropical air from the Gulf of California suddenly finds itself being pulled into the dry Arizona landscape. With this influx of warm, moist air, the North American Monsoon begins. Storms pop up all over Arizona and the rest of the Southwest, but this rain doesn't come in the form of widespread and gentle storm fronts as it often does in Ohio. Instead, isolated, but intense, thunderstorms with torrential rainfall form around the region, dotting the landscape. On one typical July day during the summer field season, the dorms at the Appleton-Whittell Research Ranch in Southeast Arizona were surrounded by these monsoon thunderstorms.

The monsoon storms are a welcomed event for those living in the hot Sonoran Desert and semi-desert grasslands. Rain means a short respite from the soaring temperatures. But for a male tarantula, the rain means love is in the air. The monsoons signal the start of the mating season for the tarantulas in Arizona, and males begin an epic quest to find females. Males throw all caution to the wind and spend all the waking hours of the day wandering in search for a female tarantula's burrow. Since the females tend to stay in their burrow unless driven out by starvation or by a predator, it comes down to the males to seek them out. And that brings us to this male that we found hanging out on the dormitory at the Appleton-Whittell Research Ranch.

Meet the...uh... I'll be honest, I'm not sure what this species is.  Dr. Chris Hamilton, the author of the paper I discuss below, reached out to me and identified this as Aphonopelma chalcodes, the Desert Blonde Tarantula. The location (SE Arizona), habitat (semi-desert grassland), and golden carapace all help key this individual out to A. chalcodes. The Desert Blonde Tarantula is a tarantula in the genus Aphonopelma. Aphonopelma is one of the 100+ genera of spiders in the tarantula family (Theraphosida), and all of the native tarantulas in the United States belong to this genus. Although it is easy to get a tarantula in the western US down to genus, getting an individual down to the species level can be very difficult. In fact, no one is really sure how many species of Aphonopelma tarantulas are in the US, mainly because the Aphonopelma genus is (well, used to be) a complete taxonomic mess. But why though?

Okay, it’s time to delve into some science. What is a species? Although it seems like a simple question, it turns out it’s quite difficult to define what a “species” is, and it’s even more difficult to have the majority of biologists agree with a single definition. Most people have been taught that a species is a group of animals which can freely reproduce with each other. This is not really correct however, as many different species can hybridize with each other. The concept of a species is more complex than that. So then, what is a species? Well, there’s a lot of different concepts. In fact, there’s more than two dozen species concepts, and a list of the 26 most common ones throughout recent history can be seen here. Nowadays, most biologists define a species using the Unified Species Concept. This concept defines a species as a separately evolving metapopulation lineage. This definition isn’t as confusing as it may sound, and if you want to read all about it, please see Kevin de Queiroz’s 2007 paper at this link. I won't get into the details of the Unified Species Concept, but just know that our changing definition of a species has resulted in some problems when it comes to classifying animals.

Historically, animals were classified into species according to differences in morphological (or physical) characteristics. Aphonopelma tarantulas were one such group of animals. They proved quite a challenge though. As it turns out, many Aphonopelma tarantulas look very, very similar. Classification based on morphological characteristics became difficult, and the genus descended into a taxonomic chaos. Then everything changed when it became possible to look at the genetics of an organism. Being able to see how closely related or diverged one organism’s DNA is to another revolutionized the field of systematics (the field of classifying animals). With this new approach, scientists began classifying species based on their DNA. This approach uncovered an interesting secret. Scientists were finding that some animals which looked exactly the same (and therefore were thought to be the same species) actually had very different DNA. Thus the concept of a “cryptic species” arose. A cryptic species is one which looks exactly like another species, but in reality is a completely different one. A non-tarantula example of this would be the Northern and Southern Ravine Salamanders, which were previously thought to be a single species as they look exactly the same, but DNA analysis in 1999 revealed two separate species.

Of course, scientists decided to re-evaluate the Aphonopelma genus using a genetic approach. Maybe this would reveal some truth in the current taxonomic mess that was Aphonopelma. I want to stress that doing something such as revising an entire wide-ranging genus is a tremendous undertaking. First, genetic work is expensive. Second, you would need DNA samples from hundreds and hundreds of individuals in order to get a representative view of the evolutionary relationships, as tarantulas are so wide-ranging (they span throughout the south from the Mississippi River west to the Pacific Ocean). Getting enough samples is not only expensive due to the traveling necessary, but is also incredibly time intensive.

And this is exactly the undertaking that Chris Hamilton, Brent Hendrixson, and Jason Bond took on. This team of scientists from Auburn University and Millsaps College just published (Feb. 2016) a massive revision of the Aphonopelma genus. In this study, they combined the relatively new genetic methods of classification with the classical morphological and ecological methods in order to “delimit” the species within the genus. This integrative approach is much more effective and thorough than simply using any one technique alone. Before this study, there were 55 Aphonopelma tarantula species described in the US. This study found that there were actually only 29 true species. Only 15 of the 55 originally described species were supported by their findings. In addition, they described 14 new cryptic species. The rest of the originally described species were found to be either unsupported or a case of a single species getting named twice or more by separate scientists.

However, the authors pointed out that this is only the start. Although they sampled 1000+ tarantula individuals from a wide range of localities, there are probably many more species out there that they simply didn’t come across. Between incredibly remote and rough terrain, and the difficulty of finding individuals in the wild, it is probably nearly impossible to completely sample every species in the US. There are surely more species out there, but many of those are likely to be highly localized or in hard to access localities. If you want to learn more, I highly recommend reading the first several pages of this giant study (which comes in at a staggering 340 pages). The paper can be found at this link. 

 

I think it's safe to say that a lot of people probably fear tarantulas. They're big, they're fuzzy, and, gasp, they're spiders. Now, I love spiders, but I can understand the fear. Though, as with many animals, much of that fear is rooted in misunderstanding. Tarantulas in the United States aren't dangerous. None of the American species have dangerous venom. A bite from one is equivalent to a bee sting. It's not going to feel pleasant, but it's nothing to freak out about either. American tarantulas rarely bite though. A more common line of defense in the Aphonopelma tarantulas is their use of urticating hairs. These tarantulas have species bristles on their abdomen that, when the tarantula feels threatened, can be "thrown" off with their legs. The tarantula will throw these bristles toward the threat, where they will embed themselves in the skin. These bristles then cause irritation to a varying degree, depending on the species. This irritation is essentially just an uncomfortable burning sensation. It's similar to the kind of reaction you would get from touching Stinging Nettle. Even so, American tarantulas are pretty docile. It really takes some harassing for them to defend themselves, and that level of harassment should never even happen. If you leave a tarantula alone, they pose literally no threat to you at all.  

This is one of my favorite photos from the summer. I had set up a simple white backdrop in the lab for photoshoots with the lizards, and we decided to put the tarantula in it. He was a good sport for me and allowed a few shots before wandering off the backdrop and onto the table. I know not everyone will agree with me, but I think they're magnificent creatures. Finally seeing a tarantula in the wild has fulfilled a wish I've had since I was a very small child.

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This post ended up being a lot longer than what I had planned, but my intent on identifying this tarantula to species took me down the systematic rabbit hole. This post is a bit more science-heavy than usual, but hopefully I explained the concepts well! If you have any questions, or want a more in-depth explanation of something discussed, feel free to drop me a comment below! Thanks for reading! I would also like to thank Dr. Chris Hamilton for identifying this individual to species.

Spiders, Spiders, and More Spiders

So it's been awhile since I've lasted posted, more than a month actually. I've found myself in sort of a writing rut, and school has been a busy whirlwind of things to do so far this semester. I haven't been able to get to writing like I've wanted too. Excuses aside, I'm back.

A jumping spider (possibly Paraphidippus aurantius) chows down on a fly.

So here I am, writing a new post. This one is about a group of much feared, much hated, much maligned animals. Spiders. Why dislike spiders? I think most of that is societal. Most children are taught to dislike and fear spiders. "They're dangerous," or "They're scary." They keep that mindset as they grow up and end up passing that mindset onto their own children, perpetuating the completely-unnecessary and inane spider hate we have in our culture.

Are spiders really dangerous? A few species are dangerous. But dogs are dangerous, and horses, and most other pets. Yet people love dogs, horses, cats, and the like. We acknowledge those animals can hurt us, but we respect them in such a way that we minimize the risk of getting hurt. This is exactly how we should treat dangerous spiders, or any animal really. You don't go up and hit a stranger's dog, or any dog; that is asking to be bit. No one blames a dog that bites a person when it feels like its well-being is threatened and it must defend itself; and just like the dog, we should not hate spiders simply because we might force an individual into a predicament where that individual fears for its well-being and bites us. That is our fault, not the spider's.

A large, but completely harmless, wolf spider of the genus Schizocosa.

Almost all spiders are venomous, but that venom is almost always too weak to hurt a human. There are a few species of spiders with venom that can harm a human. In Ohio, we have up to three species of truly dangerous spiders. The first two are black widows, specifically the Southern Black Widow (Latrodectus mactans, photos here) and the Northern Black Widow (L. variolus, photos here). Both species are highly uncommon, but can be found throughout Ohio. They are shy, rarely encountered spiders (I've only seen one, and I've been looking for them), and a bite from them, while painful and often requiring medical attention, will almost never end in death for a healthy adult.

The last dangerous spider species is the Brown Recluse (Loxosceles reclusa, photos here), depending on who you talk to and what range maps you look at. It is unsure if we have native Brown Recluses in Ohio; ODNR says there have been no verified specimens from outdoors, but that doesn't necessarily mean they aren't there. The very few that have been recorded in Ohio have been found indoors, most likely brought in by humans from elsewhere in their range, as they like to catch rides on furniture and the likes. Regardless, Brown Recluses in Ohio are very, very rare and highly restricted to the area around Cincinnati. It is important to add a note about their bite. Brown Recluses get a bad rep for their bite, which supposedly causes necrosis around the bite area. If you're seen photos of supposed bites, you know what I'm talking about. However, studies have found that only about 37% of Brown Recluse bites actually result in necrosis (the death of tissues). On top of that, studies have also estimated that nearly 80% of all "Brown Recluse bites" have actually been misdiagnoses. Most of the time it's actually MRSA, but can also be a host of other infections. The point is, Brown Recluse bites are incredibly rare due to their shyness, and even when they do bite it will most likely be harmless. If you ever see a supposed photo of a "Brown Recluse" bite, always be wary; it's more than likely something else. Another important thing to add is that doctors are not entomologists. Unless you watch a spider biting you, you can never be sure a wound was caused by a spider. On top of that, a doctor can never positively identify a spider species from a possible bite unless they have the actual spider.

Spiders do bite, there is no denying that. And in Ohio, unless they're one of the three listed here, you will be fine. Many spiders rarely bite, and it takes a lot to make them want to bite you. You have a better chance of being stung by a bee than bit by a spider. Most spiders bite when a human accidentally begins crushing one, like if you're putting on a shoe with a spider in it, or with other cases of making the spider feel in danger. Regardless, treat all spiders with respect and obviously be aware if the spider starts acting defensively, in which case they are probably to the point of biting.

The spider above is one that many people completely freak out about when they see one. Meet the Dark Fishing Spider, Dolomedes tenebrosus. Dark-Fishing Spiders are some of the largest spiders in Ohio, reaching up to a total size of 4 inches across (basically the size of your palm). While massive, these guys are totally harmless. They are really shy and will many times run away upon seeing a human. Occasionally they will wander into buildings and homes, often resulting in terror-stricken inhabitants. There's no need to worry; simply try and carefully put it in a plastic container in order to release it outside! Dark Fishing Spiders are forest spiders. They do not build a web, and instead actively hunt down prey. Look for them low on tree trunks at night, or near rocky areas with water (which is where I find most of mine).

Next up we have another fishing spider, the Six-Spotted Fishing Spider, Dolomedes triton. Spiders in the genus Dolomedes are known as Fishing Spiders as most of them are at least semi-aquatic. The previous Dark Fishing Spider is not always that aquatic and can be found very far from water. The Six-Spotted Fishing Spider, on the other hand, is the most aquatic fishing spider in Ohio. These guys are really cool. This species can actually walk on water, as shown above. They will often wait on the surface of water for prey to come by, or actively hunt prey down. Water Striders are a favorite, as are terrestrial insects that fall helplessly into water, but the Six-Spotted Fishing Spider will also hunt prey in the water. They are capable of diving up to 7 inches under the water to catch aquatic invertebrates, tadpoles, and even small fish! Pretty awesome, eh?

This tiny spider sitting on a flower is a White-Banded Crab Spider, Misumenoides formosipes. It's small, but note the characteristic white-band that runs across the face underneath the eyes. If you want a larger version of the photo, just click on it! This species, as the name suggests, is a species of crab spider, family Thomisidae. The crab spiders are so-named for their crab-like appearance. Most, but not all, crab spiders in the family Thomisidae are sit-and-wait ambush predators, as the White-Banded Crab Spider is. Basically, they sit on a plant like the one above and wait for an unlucky pollinator to come by. If the pollinator is the right size, the spider will lunge and grab it for a meal. The individual above is a male White-Banded Crab Spider. The males of this species have a golden abdomen with their four front legs being dark brown/black. The females of this species can range from gold to white. Interestingly, the females can actually change color to match the flower they are sitting on. For example, if a female picks a white flower to hunt from, she will become white, and if it's a yellow flower, she will become yellow. The males, like the one above, are locked in with their colors, however. Most of the time people are taught that the females change color in order to be camouflaged so they can be undetected by potential prey until it's too late. A relatively recent study (Brechbühl et all, 2006) has found that this is not the case; color-matching individuals had the same success rate as mismatched-colored individuals. The actual meaning behind changing colors is still up for debate, but it most likely isn't for better hunting success.

And last we have one of my favorites, Pisaurina mira, also known as the Nursery Web Spider. This species loves to hang out on the edges of forests, especially when there's bushes, tall grass, and other similar herbaceous plants. I always find many at A.W. Marion State Park in Pickaway County where a medium sized marsh/grassland area transitions into an established forest. These are large spiders, with some individuals I've seen approaching 2.5 inches wide (that is including the legs). They come in a range of colors, from very light yellow-brown to a dark brown. The markings are somewhat variable as well; BugGuide has a nice layout of the different variations, which you can see here. Why are these known as the Nursery Web Spider? Like the others I went over in this post, this species does not build a web to capture prey; instead it actively hunts down prey. The females of this species (and the others in the family Pisauridae) will, however, carry around an egg sac (photo here). Upon the spiderlings nearing hatching, the female will construct a "nursery" made out of web and place the egg sac inside. After the spiderlings hatch, the female will defend this nursery in order to keep her hundreds of offspring alive.

So I ended up writing a lot more than I thought I would, but I just love spiders. I love how misunderstood they are, and they're just so amazing once you can get past the whole "ew a spider" issue so many people have. If you don't like spiders, I strongly urge you to give them a chance!

Some Spiders Part II

Spiders. You may hate them. You may be apathetic about them. Or, if you're like me, you may love them. Spiders are seriously cool once you get over the fear society tries to instill in you. 9 time out of 10 they won't even bite you unless they think you're trying to kill them (like if you start to squish them). And in Ohio, there's really no reason to be afraid of them. Any of the very, very few semi-dangerous spiders here are ones you have to really search out to find, and not ones you just come across. Okay, now that that rant is over, let's look at a few cool ones I came across from summer to now.

This is a Nursery Web Spider, Pisaurina mira, found at The Ridges, Athens, OH. This is a female, and it was a really, really large individual. I've seen these before, but this one was essentially double the size of the others I've previously seen. You can identify P. mira by its eye structure, which helps in the ID of many spider species. With P. mira, the two rows of eyes go almost straight across the front of the head, versus being strongly curved. This girl was guarding her dinner from me, which you can see right below her.

Next to jumping spiders, this is one of my favorite types of spiders: the fishing spider. This specific one is a Dark Fishing Spider, Dolomedes tenebrosus, which I found at Conkles Hollow SNP, Hocking County. There are 5 species of fishing spiders in Ohio, and they're definitely the largest types of native spiders in the state. These guys can be massive; I've personally seen individuals that are 5-7 inches across if you measure leg to leg. This individual was probably 3-4 inches across, leg to leg. But while fishing spiders may be massive and scary to the surprised individual, these guys are harmless, and very, very shy. When I see one, they normally run away from me, leaving me to run after them for a photo. The Dark Fishing Spider will sometimes enter homes in Ohio (Been there, done that, mom screamed, the usual), but pose no threat to you. Last tidbit: They aren't like traditional spiders which spin webs; these guys chase their prey and ambush them!

I came across this spider at the Slate Run Historical Farm (part of Slate Run Metropark, Pickaway Co.), and boy did it catch my attention quickly. I had never seen a spider like this. The head was massive, and look at those massive chelicarae (the appendages that the fangs are attached to). Later, I learned this was a purseweb spider, and someone at the wonderful BugGuide IDed it as a Black Purseweb Spider, Sphodros niger. It reminded me of a tarantula, and sure enough they are related. Pursewebs are what are known as "primitive spiders," along with tarantulas, funnelwebs, and others, and are some of the least evolved spider species. Their hunting technique is also unique compared to other spiders. They build a web tunnel and conceal it. When a bug lands on it, the purseweb spider will burst through and pull the surprised bug into the tunnel to become its next meal.

Many spiders in Ohio are very tiny, but nonetheless can still be very flashy. This is an Araneus pratensis, a species of orbweaver currently with no common name. And that's a piece of prairie grass at Lynx Prairie, Adams County, that it's on. I actually didn't even notice all the colors and designs on it until I got home because it was just so tiny.

And last, here's a wolf spider! As to what species... I don't know. Someone got it down to the genus Schizocosa, but couldn't get any farther. There are currently 10 species in Schizocosa listed in Ohio, and a few could be ruled out, but we could never decide on a definite one. Anyway, I found this individual at my house in Pickaway County, and it was a pretty large wolf spider compared to the more common ones that I see. The colors on this spider were spectacular, with browns, oranges, and creams all taking place. Wolf spiders are another type of roaming spider that actively hunts prey, versus waiting for a web to do their work.

Hope you enjoyed! Remember, spiders are your friends, not your enemies! And fish are friends, not food, Dory!

Some Spiders

Fall is upon us, and you might have noticed an increase in spiders, especially large orbweavers. You might be wondering why the sudden increase in spiders, but there actually hasn't been an increase.  The spiders people are noticing now have been spending the entire summer eating bug after bug and using that energy to grow larger and larger. Of course, the larger the spider (or any animal for that matter), the better the chance people have of noticing it. The majority of these conspicuous spiders are females. They've been trying to gain mass (and therefore energy) to produce the eggs for the next generation. Spiders are a varied bunch and have a variety of life cycles. While some spiders, especially web-spinning spiders, can live for a handful of years, most individuals don't even make it through the summer due to predation, parasites, and other factors. Many will hatch in the Spring, live through the Summer, lay eggs, and then die in the Autumn (as everyone familiar with Charlotte's Web knows).

Natural histories aside, here's a few very cool spiders I recently found at A.W. Marion State Park, in Pickaway County, Ohio.

Spider number one. This is a Hentz's Orbweaver, or Neoscona crucifera. I found it hiding out on the half mile trail located near the dog beach. It was a pretty large spider, and that is even with it sitting all bunched up like this. Orbweavers, like this one, are well known for the circular webs they spin, the "classic" spider web if you will.

Orbweavers, family Araneidae, come in a wide variety of colors and patterns. For example, the previous one we saw was reddish-orange, while this one is much darker with contrasting white patches. This species is the Arabesque Orbweaver, Neoscona arabesca. This one was also hiding out among the vegetation waiting for night to come. Once the sun starts to set, this female will come out and rebuild that classic orb web to try and catch some goodies, like maybe a Bristly Cutworm moth. Web-spinning spiders, such as orbweavers, actually rebuild their web every day, which might come to a surprise to most people. Although the material is relatively strong, daily wear on a web creates holes while "trash" might also collect at the same time, making the web more visible to potential prey. To ensure a productive night, these spiders will tear down their old web and build a new one for that day.

Since we're on the subject of orbweavers, let me introduce you to the Furrow Orbweaver, Larinioides cornutus. If you live in the country, you're probably well familiar with these spiders, but maybe not by name. I know that where I live, there are hundreds of them that call the sides of my house home. They range in sizes, with some getting quite large, but are quite harmless. They might bite when provoked, as most spiders do, but that's the only bad part. No nasty venom or anything. There are three species of furrow spiders, genus Larinioides, but you can identify this species by the lack of a dark middle band on the metatarsus. The metatarsus is the second to last part of the leg; you can see a diagram of a spider leg to see where I'm talking about at the following link: Spider Leg Diagram. Notice how this individual has a dark band at the end of each leg section, but it doesn't have a second dark band on the metatarsus. This designates it as the species Lariniodes cornutus.

Here's the other side of a Furrow Orbweaver. Notice the bristly leg hairs that many orbweavers have. Orbweavers' diets typically consist of moths, and some of the Furrow Spiders at my house have it made. There are four or five individuals that make their webs around my backyard light. This light attracts moths, the moths go to the light, hit the webs, and bam, buffet for the spiders. 

Another very common spider is the Grass Spider. They are apart of the Agelenidae (Funnel Weavers) family. These are unrelated to the deadly Funnel Web Spider of Australia, mind you. You probably know these guys from their webs, which have a tunnel in which they normally sit. They sit at the end of this tunnel and wait for a bug to land. When one does, they dart out and give the bug a quick bite to kill it. This individual was very photogenic, and barely batted and eye when I was inches away snapping photos. Typically Grass Spiders are very skittish, and any change in lighting or vibration in their web which isn't reminiscent of an insect will make them quickly retreat into their protective tunnel. If you want to see one of these spiders in action, grab a small stick. Very gently, tap a section of their web as if it's an insect that just became stuck. If you're convincing, the spider will run out and bite the stick. Of course, the spider will quickly realize it isn't an insect and will run away, but it's really awesome to watch them hunt. Each spider seems to have its own personality (some are more shy than others, while others will investigate any kind of movement in their web), so you might have to try this with a few individuals to get it to work.

Slight tangent, but I need a good macro lens. My kit lens doesn't cut it for these smaller spiders. Anyway, back to spiders. This is the common Trashline Spider, or the Trashline Orbweaver, scientific name Cyclosa turbinata. There are actually two kinds of Trashlines, and the species turbinata can be told apart from conica by the female's anterior dorsal humps, which you can see here.

Trashline Spiders are interesting because of their camouflage. They collect debris of eaten insects and line it up and down in their web. They look like this "trash" themselves, and bugs don't even know there is a spider there. The females sit in the middle of their web, and the middle of the trash line, patiently waiting for an insect to get stuck in their web. 

Spiders are really awesome once you get past the initial "ew" and fear factor we have. Next time you see one, especially an orbweaver, take a closer look. Really look at their details. You will be amazed.