Spiderday (#23) – Happy Holidays

SPIDERDAY is finally back – it’s been a few weeks, but the end of the term has been hectic. However, it’s time to catch up on some great Arachnid-themed links from the last little while.

This will also be my last post of 2015, so I’ll also take this opportunity to THANK YOU for reading and commenting on this blog. I also wish everyone a Happy Holidays! Arthropod Ecology will certainly keep on truckin’ in 2016.

Here's looking at you... A close up of an Araneidae, from Insects Unlocked.

Here’s looking at you… A close up of an Araneidae, from Insects Unlocked.

Collectors cards, Arachnid style.

Collectors cards, Arachnid style.

Heating, cooling, and trying to drown Arctic pseudoscorpions

The Beringian Arctic pseudoscorpion is a charming Arachnid, living under rocks near sub-arctic rivers and streams, in primarily unglaciated parts of the Yukon. It has captured my fascinating for years, and the story of its natural history is starting to unfold. However, some fundamentals about the biology of Wyochernes asiaticus remain unknown: as the most northern pseudoscorpion in North America, how does it survive in such cold climates? How is it adapted to frequent flooding that occurs in its primary habitat, next to streams and rivers?

The Arctic pseudoscorpion, Wyochernes asiaticus

The Arctic pseudoscorpion, Wyochernes asiaticus

Science is a collaborative process, and I teamed up with two thermal biologists to start to answer some of these physiological questions. PhD student Susan Anthony and Prof. Brent Sinclair*, both from Western University in Ontario, came to the Yukon with us last summer, and together we collected pseudoscorpions at Sheep Creek, just north of the Arctic Circle. Part of Susan’s PhD research is about the thermal biology of Arachnids, so Susan and Brent wanted to see what we could learn about Arctic pseudoscorpions. They brought the wee arachnids back to Ontario, and Susan ran a series of experiments, resulting in a recent publication (in Polar Biology).

Susan Anthony and Brent Sinclair, both from Western University.

Susan Anthony and Brent Sinclair, both from Western University.

The experiments may sound a little cruel, but they are the standard approach when studying some of the cold tolerance, thermal biology and physiology of arthropods. Susan heated up and cooled down the critters, and discovered that they can survive up to about 38 degrees Celsius, and down to about -7 degrees Celsius. The upper threshold is relatively low compared to other arthropods, which makes sense since W. asiaticus lives at high latitudes. Because the specimens didn’t survive freezing, we know it’s ‘freeze avoidant’ rather than ‘freeze tolerant’. This is aligns with what we know from many other northern (or southern! i.e, in the Antarctic) arthropods. Presumably the pseudoscorpions adapt to the north by being able to supercool, or perhaps by cryoprotective dehydration,. However, its lower threshold isn’t that low, given the extreme cold winter temperatures in the Yukon. But since our collections were in the mid-summer, this might mean it’s not yet started to adapt, physiologically, for the colder winter conditions.

The next experiments involved immersing the pseudoscorpions in water and seeing how long they survive. This was done because we were very curious to know how these tiny animals might live in habitats that flood frequently. Amazingly, 50 percent of the arachnids survived under water for up to 17 days (!), and after testing with de-oxygenated water, Susan had a similar result: they certainly weren’t relying on oxygen in the water for breathing. Susan did notice, however, that they appeared to have a silvery bubble or ‘film’ around their bodies when immersed so we assume they used this air bubble for breathing during the immersion period, something known from other arachnids.

Sheep Creek, Yukon - a habitat that frequently floods: now we know how the tiny Arachnids survive the flooding!

Sheep Creek, Yukon – a habitat that frequently floods: now we know how the tiny Arachnids survive the flooding!

Putting this in the context of the pseudoscorpion’s habitat in the Yukon: it seems that the sub-arctic rivers in the Yukon typically flood for periods up to 10 days, in the spring. Our little arachnid likely just hunkers down in their habitats under rocks, breathing from air trapped around its body, waiting for floodwaters to recede.

I’m very excited about this paper, in part because of what we have learned that links the ecology of the species to its physiology. I’m also excited because this work represents a major advancement in the fundamental knowledge about Arachnids. Our work is the first to uncover any basic biology related to the physiological adaptations of pseudoscorpions to cold/heat and to immersion tolerance.

This is kind of stunning: the Pseudoscorpiones are an entire Order of Arachnids, yet nobody has ever worked to figure out how they adapt, physiologically, to extreme environmental conditions. AN ENTIRE ORDER! And it’s 2015! An analogy would be figuring out that some butterflies (Order Lepidoptera) bask in the sun, to thermoregulate. Or, like figuring out how ducks (Order: Anseriformes) don’t freeze their feet when standing on ice. These are ‘textbook’ examples of thermal biology and physiology – such facts could be considered common knowledge. Yet looking to the Arachnids, the story of the thermal biology of pseudoscorpions has only just begun. One paper at a time, we will continue to make progress.

The Arctic pseudoscorpion: it has stories to tell. Photo by C. Ernst, reproduced here with permission.

The Arctic pseudoscorpion: it has stories to tell. Photo by C. Ernst, reproduced here with permission.

As Tschinkel & Wilson state, every species has an epic tale to tell. Even tiny arachnids that live under rocks above the Arctic circle are proving interesting for many scientific disciplines: each chapter of its story is starting to unfold, and I’m quite sure there are a lot of very interesting chapters still to come.

Reference:

Anthony, S.E., C.M. Buddle and B.J. Sinclair. 2015. Thermal biology and immersion tolerance of the Beringian pseudoscorpion Wyochernes asiaticus. Polar Biology.

——

*A sincere thanks to Brent and Susan for including me on this paper, and for being willing to come to the Yukon with our team, to do collaborative research. I’ve learned a great deal in the process, and am delighted that partnerships between ecologists and physiologists can work out so well.

Questions and answers about spiders

Spiders, spiders, everywhere. I get asked a LOT of questions about spiders – from students, friends, neighbors, over twitter, and from journalists. I recently spent some time talking to a journalist in my hometown about spiders in Quebec*, and thought to share the details here! Here’s a copy of some of the Q&A with the journalist:

A beautiful dock spider (photo by Sean McCann)

A beautiful dock spider (photo by Sean McCann)

Q1) Why your obvious fascination with spiders?

Spiders are fascinating because they have remarkable biology and life history, and are certainly as beautiful as all other animals. They are the top predators in their own world, feeding on insects that may cause economic damage to our crops, or catching mosquitoes that seek us out for a blood meal. They build stunning webs, have remarkable diversity of body types and the live almost everywhere on the planet (all terrestrial parts, except the Antarctic). As babies the ‘balloon’ up into the air, and are among the best dispersers in the world – better than many flying insects. They are among the most common animals in ecosystems – we have recorded, for example, that wolf spiders occur in densities of over 1 spider per square m in parts of the Arctic tundra. What’s not to love?

Q2) How long have you been interested in them and why do you think they have a bad rap with so many people ?

I became interested in spiders when I was doing my undergraduate degree at the University of Guelph. A botany Professor there was working on the old cedar trees growing off the cliff faces of the Niagara escarpment, and during one summer he hired me to help with that work. While hanging off cliff faces, I couldn’t help but notice SO MANY SPIDERS and this piqued my curiosity, Professor Larson then allowed me to do a research project in the lab, and I did that project on spiders. Like to many things … a little knowledge is a dangerous thing. As I learned more, I became more and more fascinated by Arachnids, and continued on to do another undergraduate research project on spiders, and it just continued and continued until this day. I have been working with spiders now for over 20 years of my life.

Arachnophobia is real and serious for many people, but in many cases, people are not necessary arachnophobic, but rather have a general (unfounded) loathing for spiders and I believe this is largely because they have not explored their incredible biology and natural history. With education, I find people can shift from fear to curiosity and amazement. There have been studies done that illustrate that the ways that spiders move, and their extra legs, may contribute to a general fear of spiders – in other words, they can surprise us and are so “Leggy” that it causes a startle reaction and this perhaps leads to fear. This is very common in our society, and this feeds a cycle of fear, as our children learn fears from us. There may be some genetic basis to being afraid of spiders, also, and this probably relates to the fact that some spiders are indeed venomous to humans. In this part of the world, however, there are very few spiders of medical importance, and spider bites are exceedingly rare. Although everyone has a story about a spider bite, most of these are not verified, and other more likely causes should be investigated. Misdiagnosis is common in the medical field, also.

Q3) Why are they beneficial in the garden? And, even in moderation I assume, in the home ?

Spiders are beneficial because they eat many insects that themselves can be harmful to our gardens. In our homes they also feed on other insects that live in our homes. Without spiders, we would certainly have more other critters in our house and garden.

A cellar spider, with prey (c) A. Bradford

A cellar spider, with prey (c) A. Bradford

Q4) How many types of spiders do you think we have in this region and what would you estimate their total population to be?

There are over 40,000 different species of spiders in the world, over 3,000 species known in Canada, and over 600 species known from Quebec. That is a LOT of different kinds of spiders! There are certainly more species of spiders in the world than there are mammals or birds. I estimate an average yard in any small town in southern parts of Canada harbour easily 20-30 different species, and our local forests certainly can have over 100 different species.

It’s difficult to estimate population (i.e., how many of each kind of spider), but it’s fair to say that the old saying that you are always within three feet of spider is likely quite accurate, at least when you are in natural environments. The sheer biomass and density of spiders in some parts of the world is truly astounding.

Q5) What are some of the most common kinds of spiders?  What do they do during the winter?

Common spiders in our homes include things like the “Zebra jumper” Salticus scenicus it’s the little black and white jumping spider that is common in our window sills or on the walls of our houses, especially on warm summer days. Many of us have the Cellar spiders Pholcus phalangioides in our houses (they have long, gangly legs, but are not to be confused with “Daddy long legs – aka Harvestmenpersons – they are cousins to spiders, but not actually spiders!). In our gardens in the late summer, we see many individuals of the black-and yellow garden spider Argiope aurantia – it’s very large, with black and yellow striping on its abdomen, stringing up its huge webs in our gardens. Another very common orb-weaving spider, that also matures in the late summer, is Neoscona crucifera. We often see funnel-web or grass spiders (Agelenopsis) on dewy mornings: they can build their sheet-webs (with a funnel retreat at one end) on shrubs or on our lawns, in very high densities – obvious with a heavy layer of dew. We also find Canada’s largest spider in southern Quebec – an impressive animal!

The cute Zebra jumper (By Alex Wild)

The cute and common Zebra jumper (By Alex Wild)

Spiders do various things in the winter – in some cases the egg cases overwinter, and in other cases the spiders overwinter. Most spiders are “freeze avoidant”, meaning that they cannot freeze without dying, so they often adapt by ‘supercooling’ which essentially means they produce antifreeze in their bodies so they will survive below freezing temperatures. Spiders generally find places to hide in the winter, whether it’s in leaf-litter, under rocks, or finding a way into our warm basements.

Q6) Do you have a personal favourite spider?  If so, why, and what is it called?

I really like the ant-mimicking jumping spiders such as Peckhamia pictata  – it occurs in Quebec, and is a marvellous mimic of ants – most people don’t notice it because it fools us by its shape and behaviour – and so very easy to mistake as an ant instead of a spider. There are, in the world, about 300 different species of jumping spiders that mimic ants – a behaviour that is more common in the tropics, but also happens with some species here in the north.

Q7) How long have spiders been around on Earth and how long do spiders, on average, live?

Spiders have been around for perhaps 400 million years, which is a very, very long time. They have been on this planet far longer than us!

In this part of the world, spiders typically live one year, although some larger species may take more than one year to reach adulthood. In captivity spiders can live a very long time – I have a Tarantula named Harriet, in my lab at McGill, and she is approaching 20 years old.

© C.M. Buddle (2015)

*indeed, this Q &A was Quebec-focused, so may not be generalizable to all parts of the world!

Spiderday (#22)

It’s been a couple of weeks, but nevertheless, here is another edition of SPIDERDAY! All the best Arachnid-themed links, pulled from the web in the last little while.

Just look at this Jumping spider keeping an eye on her babies! Photo by Nick Porch (reproduced here with permission)

Just look at this Jumping spider keeping an eye on her babies! Photo by Nick Porch (reproduced here with permission)

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Spiderday (#21)

Spiderday! Here’s some Arachnid-themed links I stumbled across over the past week.

Spiderday (#20)

What a great day. It’s Halloween AND spiderday. On the same day. And it’s the 20th edition of spiderday. It just doesn’t get any better.  Here are the arachnid-themed stories I pulled from the web over the past week.

But first… just LOOK AT THIS amazing little spider:

A mystery 'tube spider' by Daniel Llavaneras.

A ‘tube spider’ (genus Dipoena) by Daniel Llavaneras.

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Spiderday (#19)

It’s been a few weeks since the last SPIDERDAY (sorry…). Here’s another edition of this feature, with links to some of my favourite stories about Arachnids. It was easy to pull this together this month, since it’s  Arachtober.

This is a lovely spider species in the family Titanoecidae. (Photo by Sean McCann)

This is a lovely spider species in the family Titanoecidae. (Photo by Sean McCann)

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Ctenus exlineae

Ctenus exlineae

The natural history of teddy-bear solifugids: cuddly wonders of the desert

This post was written by Michael Kent, with minor edits from C. Buddle. Michael is a naturalist at Killbear Provincial Park. Both Chris and Mike are very devoted to continue to improve the public image of Arachnids. This post by Mike will surely help… 

More chelicera than cephalothorax, the Solifugae or “those who flee from the sun” look like a reckless arachnid bulldozer that could star in Mad Max. Otherwise known (incorrectly!) as camel spiders, whip scorpions, and my personal favourite baarskeerders (Afrikaans for beard cutters), solifugids are often one of the dominant arthropod predators in arid ecosystems. They ruthlessly chase, hunt, stalk, and scavenge using their leg-lengthed pedipalps to snatch prey while using their jaw-like chelicera and digestive juices to masticate their invertebrate and small vertebrate victims to a pulp.

Competing for one of the cutest arachnids is this Teddy Solifugae (Hexisopus sp.). Not just for petting, the fuzzy mat of hairs covering its body are mechanoreceptors capable of detecting miniscule changes in temperature, humidity, and air movement. Photo by M. Kent.

Competing for one of the cutest arachnids is this Teddy Solifugae (Hexisopus sp.). Not just for petting, the fuzzy mat of hairs covering its body are mechanoreceptors capable of detecting miniscule changes in temperature, humidity, and air movement. Photo by M. Kent.

Like most arachnids, solifugids don’t get much positive media attention. Famous on the internet by “forced perspective” photos makes them appear to be much larger and scarier than their modest 15cm maximum. There is even a photo of an intimidating, solifugid-like creature constructed by a talented invertebrate artist that has many fooled. As formidable as they look, they are likely non-venomous, with bites being rare and only resulting in localized pain and swelling in humans (Naskrecki, 2012).

When it comes to cuteness in the arachnid world, salticids are the reigning champions with their captivating eyes and fancy footwork. Normally ranking near the bottom, solifugids have a new challenger for the world’s cutest arachnid with the teddy bear solifugid family, the Hexisopodidae. Observed while on a trip to Namibia in January, this family is endemic to South Africa and look more like “baarskeerdlers” (beard cuddlers) rather than a baarskeerders. Surrounded by an arid lunar landscape, one was observed slowly waddling (extremely atypical for most solifugids) in the dry, sandy riverbed in a gorge in Damaraland.

Also known as mole solifugids, as soon as it sensed us, it buried itself beneath the sand and disappeared. A member of the family Hexisopodidae, it is characterized by adaptions to a mysterious subterranean lifestyle with fossorial 2nd, 3rd, and 4th legs, with the 4th lacking tarsal claws (Savary, 2009). Overall, not much is known about the life history of the Solifugid order other than some broad generalizations based on detailed observations of just a little more than a handful of different species.

Not meant for speed, solifugids in the Hexisopodidae family are equipped with fossorial 2nd, 3rd, and 4th legs. Photo by M. Kent

Not meant for speed, solifugids in the Hexisopodidae family are equipped with fossorial 2nd, 3rd, and 4th legs. Photo by M. Kent

From what we know solifugids typically only live one year or less, and burrowing is an important part of their life. When they’re not spastically running about searching for food, burrows serve as a daytime refuge providing proper humidity, a safe retreat from predators, or protecting during vulnerable times when molting, digesting, or depositing eggs (Wharton & Reddick, 2009). Eggs take anywhere from 2 days to 2 months to develop into larvae, dispersing at the 2nd instar, and going through 4-8 nymphal instars before becoming an adult (Wharton & Reddick, 2009). It is unknown whether the Hexisopodidae have similar life-history traits. How much time do they spend underground? Why do they go underground? Do they hunt for food by searching in the sand or ambushing?

One of only two known genera in the Hexisopodidae family – Chelypus and Hexisopus – can be morphologically distinguished from each other by the presence or absence of well-developed spines on the pedipalps. Photo by M. Kent.

Solifugae taxonomy is messier than a cobweb. Whether solifugids share a more recent common ancestor with pseudoscorpions or mites is still debated. They all share certain features of the mouthparts. Solifugae and acariform mites have a potential synapomorphy in their sejugal furrow, while solifugae and pseudoscorpions share several characters such as similar tracheal respiratory systems (Dunlop, & Penney, 2012). The solifugae Order consists of 12 families, 141 genera and 1095 described species (Savary, 2009). However, some families are too arbitrarily defined and lump genera, while others are too narrowly defined and split genera creating a phylogenetic cobweb. Revising solifugid systematics needs to start from the ground up.

Recently, a team of researchers funded by the American Museum of Natural History did just that and presented a comprehensive analysis of cheliceral morphology for Solifugae by taking high-res images of the jaws of 188 different species, comparing them with existing literature, and identify and reinterpreting structures based on primary homology. It is crucial to be on board with the same jaw terminology because it is an important morphological character set containing relevant information for identification and sexing (Bird et al. 2015)

Solifugids also share various other morphological characters including malleoli and suctorial organs. Chemosensory malleoli or racuquet organs located on the underside of their 4th pair of legs. Analogous to scorpion’s pectin, the series of fan-like structures is thought to play an important role in the detection of food, predators, and mates (Punzo, 2012). The suctorial organs located at the tip of the palps are used to apprehend potential prey and climb vertical surface. The latter was observed as a solifugae was observed clinging to a window near the Monteverde Cloud Forest in Costa Rica.

One of only a handlful of solifugid species found in wet, tropical environments. This solifugae was observed in the Monteverde Cloud Forest clinging to a window using its sutorial organs

One of only a handlful of solifugid species found in wet, tropical environments. This solifugae was observed in the Monteverde Cloud Forest clinging to a window using its sutorial organs. Photo by M. Kent.

Solifugids are even found in Canada! At the northern limit to their range, suitable semi-arid habitat is found in the coulees and badlands of Southern Alberta, in the cities of Lethbridge and Medicine Hat, Southern Okanagan Valley of BC, and a Southern Saskatchewan (Johnson, 2004).

Next time you are visiting arid parts of the world, do watch out for these fascinating Arachnids. They are worthy of our attention, especially since so much of their natural history remains unknown. Cuddle up to “baarskeerdlers”, and be amazed.

Text and photos © M. Kent (not to be reproduced without permission)

Equipped with the largest invertebrate jaws for its body size, solifugids don't need venom. They masticate their victims instead, relying on their huge head muscles to power their exoskeleton crunching chelicera. Photo by M. Kent.

Equipped with the largest invertebrate jaws for its body size, solifugids don’t need venom. They masticate their victims instead, relying on their huge head muscles to power their exoskeleton crunching chelicera. Photo by M. Kent.

References

Bird, T., Wharton, R., & Prendini, L. (2015). Cheliceral Morphology In Solifugae (Arachnida): Primary Homology, Terminology, And Character Survey. Bulletin of the American Museum of Natural History.

Dunlop, J. A., & Penney, D. (2012). Fossil Arachnids. Siri Scientific Press.

Johnson, D. (2004). Scorpions in Canada. Retrieved from University of Lethbridge: http://people.uleth.ca/~dan.johnson/htm/solpugids.htm

Naskrecki, P. (2012). Solifugids – arachnid teddybears (with big teeth). Retrieved from The Smaller Majority: http://thesmallermajority.com/2012/11/09/solifugids-arachnid-teddybears-with-big-teeth/

Punzo, F. (2012). The Biology of Camel-Spiders: Arachnida, Solifugae. Springer Science & Business Media.

Savary, W. (2009). Hexisopodidae. Retrieved from Homepage of The Arachnid Order Solifugae: http://www.solpugid.com/Hexisopodidae.htm

Wharton, R. A., & Reddick, K. (2009). Life History. Retrieved from The Arachnid Order Solifugae: http://www.solpugid.com/Life%20History.htm

Arachtober

We are in for a great month. It’s not October… it’s Arachtober. It’s a month to celebrate all things Arachnid, from photos, to blog posts and stories about our eight-legged friends. It’s a month to appreciate Arachnids for what they are: stunningly beautiful animals.

A beautiful long-jawed orb-weaver (image by Alex Wild, from "Insects Unlocked".

A beautiful long-jawed orb-weaver (image by Alex Wild, from “Insects Unlocked”.)

To get all set for Arachtober, here are some ways to get involved and to learn about spiders:

First, do check out Africa Gomez’s blog – she’s promised to do daily (yes, DAILY) posts about spiders. Yay!

Be sure to follow Catherine Scott – she is on a terrific campaign to help educate people about spiders, and calm down the nerves and assure folks that the spiders they find are *not* brown recluse spiders. 

This is Catherine Scott, wearing a t-shirt with an important message.

This is Catherine Scott, wearing a t-shirt with an important message.

Be sure to keep an eye on the Arachtober Flickr group. Amazing photos to be found there; this was the first place that Arachtober got started… members of that group tried to post new spider photos daily, throughout the month of October.

For other photos about arachnids, do check out work by Sam Martin, or Thomas Shahan, or Sean McCann, or Alex Wild, to name a few. Here’s an example of Sean’s work:

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If you want to find other Archnologists on Twitter, here’s a Twitter List for you.

Want to learn more about Arachnology? Check out the American Arachnological Society, or the International Society of Arachnology. Here’s a more general post about what to do if you want to be an arachnologist.

Arachnology has a rich and fascinating history. The Biodiversity Heritage Library is a wonderful resource: here, you can look at old titles about spiders and on their Flickr page, view stunning plates from those old books and journals.

Have some interests in drawing spiders? Don’t forget to get the anatomy correct! Here’s a post from a 10 year-old who did it right:

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Have a read through these great Arachtober posts from the past, from Bug Gwen.

Another great blog to check out, for wonderful spider natural history, comes from “Bug Eric”.

Have a spider and not sure what it is? Sometimes you can surf around on BugGuide and work towards an identification with that. It’s a great resource for Arachnophiles.

Arachtober ends with Halloween, of course. Perhaps viewing some movies featuring spiders is a fine idea.

Oh, and for Halloween, here’s how to make your 3D spider cake (um, too bad about the spider’s anatomy is all wrong. Sigh)

And, finally: SPIDER ROBOT (check around the 7:00 mark):

So, how else will you celebrate Arachtober? Share your thoughts in the comment section, below!

[As many of you know, I’ve been posting weekly with links to stories about arachnids, called “SPIDERDAY“. Given a busy travel schedule this month, Spiderday may be a bit ‘irregular’ – sorry!]

Spiderday (#18)

Whoop! Three cheers for SPIDERDAY (or would it be more apt to say “eight cheers”?. All the arachnid links from the past week, in one place.

Meet your dock spiders. Photo by Sean McCann.

Meet your dock spiders. Photo by Sean McCann.

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