Category Archives: Arachnids

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An indoor field trip: visiting Canada’s national spider collection

Last week I traveled up to Ottawa with two of my students – our goal was to visit the Arachnid collection at the Canadian National Collection of Insects (CNCI) (and Arachnids and Nematodes). The spider collection is housed on the fourth floor of the Neatby building, in a room that seldom has its lights turned on.  Canada’s National Spider collection has been without a curator since the 1990s, when Dr. Charles Dondale retired. In fact, his name is still on the door.

Dr. Dondale

The spider collection has historically been one of the finest, world-wide. It contains numerous type specimens, and houses thousands upon thousands of vials, all within stand-up cabinets. These vials contain rich biological information – they contain a spider with a species name, where it was found, who collected it, and when. These kinds of museum data are absolutely vital as we try to understand our biodiversity, and how it might be changing in the face of environmental stresses. Museum data form the basis of taxonomic revisions, and museum specimens (identified to species, by experts) are an important way for someone to learn taxonomy (that is how I did it!).

Our goal in the spider collection was to data-base some specimens – this means taking what is written on (old) labels, and entering data into a data-base (one that will eventually go on-line). On this trip, we were looking for some records of purse-web spiders in North America, and for northern black widow spider records. We also worked to database the jumping spiders (Salticidae), with a particular focus on those species occurring in Canada.

The task of data-basing.

The task of data-basing.

You might wonder why we would take time away from our own (busy) laboratory in Montreal to drive up to Ottawa to enter data; surely there are better uses of that precious resource of time (and money)?  Nope: A visit to the CNCI is always worth it.  Here’s why:

1. Label data are useful data! I have quite a few projects ongoing this summer, including a better understanding of the distribution of jumping spiders in Quebec. There’s no better way to find certain species than going to where they have been found before.  How do you know where they have been found before? Although much can be gleaned from publications, there are hundreds of specimens that have been collected and stored at the CNCI, but whose data has never been used in a publication. Looking at vials and reading labels is a good place to start, and while doing this, it only makes sense to enter the information into a data-base. It’s not exciting work, but having data digitally accessible allows my own research interests to move forward more effectively.

Treasures in the cabinet.

Treasures in the cabinet.

2. I’m an Arachnologist in Canada, and as such, I feel a responsibility to use the collection in Ottawa. The spider room at the CNCI is where (historically) Canada become a global leader in spider taxonomy. Charlie Dondale and others (notably James Redner) wrote some of the most important papers and books about spiders in North America, and their (free!) books remain a critical resource for Arachnologists throughout North America.  The hallowed grounds of the spider room are where much of this work occurred. It’s a special place, and one that is worth visiting.

3. If you don’t use it, you’ll lose it. The future is not bright for this spider collection. Surprisingly, a replacement for Charlie has not be hired. We need an Arachnologist in Ottawa (I’ve written about this before). I worry deeply for this collection, and even a few visits per year are better than none at all – it shows there is still broader interest in the spider collection, and that it remains an important resource for people from other regions of Canada. Showing continual use and interest in the collection is a great way to show its value.

4. If it’s lost, let’s hope the data are not. Time for thinking about ‘worst case scenarios‘:  every time I am at the CNCI I see evidence of further degradation of the spider collection. Spiders are stored in ethanol, long-term, and without  curation the ethanol degrades, discolours, the specimens get brittle or break apart, the labels fade or become unreadable, or perhaps a vial or two break.  The spider collection has not receive high consistent curation for a very long time. At the very least, we better have the data from those specimens, and that requires data-basing.

Trouble in the collection: A vial with a cracked glass lip.

Trouble in the collection: A vial with a cracked glass lip.

In sum, the spider room at the CNCI is a national treasure and it was really great to be there. We didn’t get much done (only about a hundred specimens databased – and, truthfully, I did very little of the hard work – my students did all the heavy lifting).  But it was a start, and means that we’ll need to come back. I sincerely look forward to the next visit!

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Expiscor (20 May 2013)

This week’s Expiscor is coming to you on a holiday Monday across much of Canada. This is the day that many Canadians feel that the ‘warm season‘ has officially arrived. We can plant things in our garden without fear of frost; the lawn shall be mowed, the birds are busy, the butterflies are flying.

What is Expiscor? …it’s a weekly digest of discoveries from the world of entomology, biology, and so much more.

  • It seems that every week there’s a story about ‘dangerous spiders‘ – this week, Bug Girl wrote a post to help FIX THE INTERNET – in this case, to discuss a bogus spider poster.
  • On the topic of jumping spiders – they can make you look twice – WOW, WOW and WOW again. (thanks Alex Wild, for that photo, and permission to use it)

Screen Shot 2013-05-19 at 3.17.12 PM

  • Biodiversity under foot – great video about threats to soil biodiversity (thanks to my former MSc student, and recent PhD graduate, Zach for posting that link.
  • Fireflies: I always find the larvae of the Lampyridae beetles to be odd-looking, and I sometimes have trouble reconciling their habitus with adults.  This is a lot easer thanks to Derek Hennen for this lovely photo of an adult – check out that abdomen! (and thanks, Derek, for allowing me to use this photo)

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  • Scale it. This is VERY worth checking out. I personally like 10 to the power of -2.5
  • A worthy ordeal: Another great post from one of my heroes, Simon Leather – a terrific tradition in the British University system.
  • Lego geek-fest. Star Wars, LOTR, Arrested Development & so much more.
  • To finish, as usual, with some music. I’ve been a fan of Steve Earle for quite a long time, and his latest album (the Low Highway) does not disappoint. Here’s a video from one of the songs from that album. Worth a listen (and a good lesson in there, too)

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Expiscor (13 May 2013)

Start your week with some discoveries: from entomology to natural history, Academia & beyond! Expiscor – a weekly digest. (you can find past editions here).

  • In other entomology news, a paper about fatigue of insect cuticle. Yes, insects do wear out, eventually (mind you, it took 100,000 cycles before the wing samples failed!).
Photo by D. Llavaneras, reproduced here with permission.

Photo by D. Llavaneras, reproduced here with permission.

  • Hipsters – that was so last year. The current fad is clearly THRIPSTERS (again, Ainsley Seago show up in Expiscor!).
  • A milestone I’d rather we did not reach: Carbon dioxide levels pass 400 ppm. Not good news. So, I suppose I should not let my car idle while I stop in for groceries, right?
  • Muzzled Government scientists in Canada – here’s a must-read article on the topic from Maclean’s Magazine.  Here’s a quote from David Schindler: ‘They’re [the gov't] all for science that will produce widgets that they can sell and tax, but it’s clear that environmental scientists are lumped right down there with Greenpeace in their view’
  • Speaking of food, this photo essay has been around for a while, but worth a look – it’s all about how groceries for a week, from around the world.  Clearly quite a lot of us overeat.
  • Achoo! Allergy season is upon us here in the Montreal area – pollen counts are apparently ridiculously high this year (yes, you can get a ‘pollen report‘).  Here’s the hood of my car one morning last week:

Screen Shot 2013-05-11 at 3.16.29 PM

  • Where in the world am I?  Great little game using Google Street View. I spent a lot of time playing with this on the weekend – amazing to see what ‘clues’ tell you where you might be. Street signs, styles of the cars, electrical lines (above ground, or not?).
  • Here’s a nice idea: suspended coffee.  Buy an extra coffee for someone who may later come along and need a coffee but be unable to pay for it.
  • Good news for Dale Boyle (a guy with more than a few McGill connections). He’s a heck of a songwriter and that was recognized recently. Incidentally, he also sold me a guitar a few years back and that was a catalyst for me to start playing music again. Although this particular video doesn’t display his songwriting skills, it sure is lovely:

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The case of the missing genitalia: copulation costs for male spiders

This post is written by Chris Buddle (Associate Professor, McGill University). This article was originally published in “The Canadian Arachnologist” – a newsletter about Arachnology in Canada (this newsletter is no longer being published). 

Spider sex can be a dangerous and costly venture, the classic example being the (often) misunderstood act of sexual cannibalism (e.g., the black widow spider). However, many of the costs for males are not always so obvious: during copulation, the emboli of some male spiders may break off, which results in the male being unable to properly re-fill his palpal organ and mate again (Foelix 1996). Without this ability, the male’s future is essentially an early retirement. While sorting and identifying spiders for my dissertation research, I noticed that male Cybaeopsis euopla (a ‘hackledmesh’ weaver spider) seemed to frequently be missing one or both of their pedipalps.  Could this be another example of a copulation cost?

Looking to the literature, missing pedipalps are documented with some species – tiny males from the sexually dimorphic genus Tidarren (Theridiidae) will remove their own palps and this increases their running speed considerably (Ramos et al. 2004). Working with the same genus, Knofach and van Harten (2001) observed that females remove one of the male’s palps ‘after achieving genitalia coupling’. The female then proceeds to eat the male, while the detached palp acts as both a mating plug and continues to inseminate the female! Something similar happens with the species Nephilengys malabarensis and this fascinating biology was reported by science bloggers such as Ed Yong. In the wolf spider (Lycosidae) Pardosa milvina, frequent palpal losses were observed and effects on courtship and mating were studied by Lynam et al. (2006). Perhaps not surprisingly, these authors report that ‘intact males were less likely to be cannibalized and suffered fewer predatory attacks by females than autotomized males’.

With that background, I began counting the frequency of missing pedipalps for a sub-sample of the specimens of C. euopla. The objective was to assess the percentage of males were missing right, left, or both pedipalps and see if this related to phenology or other life-history events.

The samples came from a mixed-wood forest at the George Lake Field Station, located about 75 km NW of Edmonton, Alberta. This mature mixed-wood forest is dominated by trembling aspen and balsam poplar. Samples were collected using standard pitfall traps, and were part of several other projects on spider assemblages in mixed-wood boreal forests (e.g., see Buddle 2001).

Cybaeopsis euopla - lovely little spiders! (Photo by C. Buddle)

Cybaeopsis euopla – lovely little spiders! (Photo by C. Buddle)

Cybaeopis euopla (Amaurobiidae) (formerly Callioplus euoplus) is widespread in Canada, ranging from the Maritimes to the far north-west (Leech 1972). Males are about 3.5 to 5 mm in length, and are pale orange to light brown in colour. Specimens are typically collected from the leaf-litter of closed-canopy deciduous forests (Leech 1972; Buddle et al. 2000). From a sample of 653 male C. euopla, I found a total of 309 (or 47%) to be missing either one or both pedipalps. This is an impressive number, and essentially means that about half the males in the population are missing the very parts of their bodies that are required for reproduction. Of the 309 that were missing pedipalps, 124 were missing the left pedipalp, 97 were missing the right pedipalp, and 88 were missing both. In virtually all cases, the pedipalp was severed at the trochanter-femur joint. So the most plausible explanations for missing pedipalps are:

  • Pedipalp autotomy occurs during the act of copulation
  • The female may remove the pedipalps before, during or after copulation
  • C. euopla males may use their pedipalps in antagonistic courtship behaviours
  • Perhaps pedipalps are frequently used to grapple with aggressive prey, and are thus damaged.

It would be difficult to relate missing pedipalps to the act of copulation without detailed studies of courtship and copulation in C. euopla. However, the fate of pedipalps could be determined indirectly if the frequency of missing pedipalps increased during the reproductive period. The period of reproduction for ground-dwelling spiders, such as C. euopla, can be assessed from the peak activity period for male and female spiders, inferred from a passive sampling technique such as pitfall trapping. Using a larger data-set for male and female C. euopla collected by pitfall traps set at the George Lake Field Station, it is evident that males are most active early in the season (early May through the end of June) (Figure 1). Females were found throughout the spring and summer months over two years, with a slight increase in late June (Figure 1). These results generally agree with Leech (1972), who suggests May and June are the main periods of activity for C. euopla. Thus, it is inferred that this species will mate primarily in the spring in central Alberta.

Fig 1

The next step is to ask whether the frequency of missing pedipalps is related to the hypothesized mating period. This was done by calculating the average percentage of males with missing pedipalps as a function of sampling date (Figure 2). In both sampling years, the percentage of males with missing pedipalps increased as the season progressed (Figure 2). Although the sample size for July samples was low (12 individuals), the average number missing pedipalps was over 80%. Furthermore, the earliest sampling date in 1999 (6 May), which collected over 200 individuals, had the lowest average percentage of males with missing pedipalps (< 20%). These results indirectly suggest that as the season progresses, and the spiders mate, males begin to lose their pedipalps. I can therefore likely exclude the possibility that palpal loss is related to aggressive prey, and the explanation is likely related to courtship or copulation.

Fig 2

This small study has raised as many questions as it has answered, and there are certainly other explanations that I have failed to mention. I invite fellow Arachnologists to comment on the phenomenon of missing pedipalps in C. euopla, and in other species.  I suspect pedipalp loss is widespread, but seriously understudied. Given this importance of palps to the fitness of spiders, future research is certainly warranted.

References:

Buddle, C. (2001). Spiders (Araneae) associated with downed woody material in a deciduous forest in central Alberta, Canada Agricultural and Forest Entomology, 3 (4), 241-251 DOI: 10.1046/j.1461-9555.2001.00103.x

Buddle, C., Spence, J., & Langor, D. (2000). Succession of boreal forest spider assemblages following wildfire and harvesting Ecography, 23 (4), 424-436 DOI: 10.1034/j.1600-0587.2000.230405.x

Foelix, R.M. 1996. The Biology of Spiders. Oxford University Press.

Knoflach, B., & van Harten, A. (2001). Tidarren argo sp. nov. (Araneae: Theridiidae) and its exceptional copulatory behaviour: emasculation, male palpal organ as a mating plug and sexual cannibalism Journal of Zoology, 254 (4), 449-459 DOI: 10.1017/S0952836901000954

Leech, R. 1972. A revision of the nearctic Amaurobiidae (Arachnida: Araneida). Memoirs of the Entomological Society of Canada 84: 1-182.

Lynam, E., Owens, J., & Persons, M. (2006). The Influence of Pedipalp Autotomy on the Courtship and Mating Behavior of Pardosa milvina (Araneae: Lycosidae) Journal of Insect Behavior, 19 (1), 63-75 DOI: 10.1007/s10905-005-9008-x

Ramos, M. (2004). Overcoming an evolutionary conflict: Removal of a reproductive organ greatly increases locomotor performance Proceedings of the National Academy of Sciences, 101 (14), 4883-4887 DOI: 10.1073/pnas.0400324101

ResearchBlogging.org

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Expiscor (6 May 2013)

Welcome to May! Expiscor is still going strong, and thanks to everyone for the continued support and interest. I’m certainly thrilled about this, and will continue to post weekly links about entomology, arachnology, natural history, biology and a dash of the curious and odd.

  • Silk farming and biotechnology: the future is here. This paper describes some things that I don’t fully understand, and I am partially fascinated by, and partially terrified about, the idea (anyone read Margaret Atwood‘s book, Oryx & Crake?).
  • On the death of a bug blog? Ted MacRae posts about waning interest by readers, and perhaps by him, with his fabulous Beetles in the Bush blog. Ted will keep posting (phew!) but less regularly. Actually, I have noticed that over the past six months or so quite a few bug blogs have been less active.  This saddens me – high quality entomology blogs are an important way for this discipline to reach a wide audience.  Come on, folks – keep them going!
  • Palpal action. and check out this stunning photo from Chthoniid!  Yes, Harvestmen are among the most lovely of the Arachnida.
A charming harvestmen. © Chthoniid, reproduced here with permission.

A charming harvestmen. © Chthoniid, reproduced here with permission.

  • Worried about the decline of bees and colony collapse disorder?  Read this –> an important message (thanks Bug Girl for posting this)
  • On-line reading – I have been enjoying Nautilus this past week. Here’s their motto: “Nautilus is a different kind of science magazine. We deliver big-picture science by reporting on a single monthly topic from multiple perspectives. Read a new chapter in the story every Thursday”.  Definitely one to follow. And it’s a lovely site to look at.
  • Avoid that mumbo-jumbo.  Here’s Alan Alda’s take on scientific jargon.  Here’s a great quote from him:  ”There’s no reason for the jargon when you’re trying to communicate the essence of the science to the public because you’re talking what amounts to gibberish to them“.  He’s right.
  • Think you’r a pretty big deal? What to think about your place in the Universe? Think again. (thanks Sam Heads for tweeting that link!)
  • Kids have an interesting fashion sense. Here’s a photo of my 9 year old, en route to school.  I wish we could all worry a little less about whether or not things might clash, and just be happy that we have clothes to wear and food to eat.
Fashion. That is all.

Fashion. That is all.

  • Unless you’ve been off the grid for months, you have probably heard of the great Canadian Chris Hadfield, up on the International Space Station. He and Barenaked Ladies frontman Ed Robertson teamed up a while ago to write and perform a song (yes, Chris was in SPACE during the recording). Well, this was all leading up to MUSIC MONDAY, which is today. A fabulous celebration about music – all the details are here.  And the video of the Hadfield/Robertson song is below. Worth a listen.
  • ….on a related note, Chris Hadfield has more twitter followers than Canada’s Prime Minster (and for good reason).
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Expiscor (29 April 2013)

As you may have noticed, the ‘weekly’ Expiscor missed last week! This is because I have opted to change to Mondays for this blog feature.  The start of the week just works better, for a whole suite of reasons that I won’t bore you with!  So, you can now look forward to starting your week with some odd discoveries, from arthropods to general biology and other geekery.

  • Most (many?) Arachnologists know of Emerton’s classic “The Common Spiders of the United States” written in 1902 – that book is now available on-line! Big WIN for spider enthusiasts.
  • Be still my heart.  Here’s a video showing the heartbeat of a spider after being captured and placed in a mud-dauber (wasp) nest.  Wasp finds spider. Paralyzes it. Returns it to its nest. Spider is still alive. A tasty feast for later on…. (thanks to Spider Joe for this video!)
  • Adrian Thysse always impresses me with his amazing photographs.  This one depicts one of the most lovely spiders in North America, Habronattus americanus.  Yes, it’s one of my most favourite spiders, here’s why:
Habronattus americanus - photography by A. Thysse (reproduced here, with permission)

Habronattus americanus - photography by A. Thysse (reproduced here, with permission)

  • If you don’t buy stuff on ETSY, you should – amazing on-line resource. Also, some lovely insects finds on ETSY, including this from GollyBard (thanks Cameron Webb for pointing me to this)
One of GollyBard's paintings - listing here. (reproduced here with permission)

One of GollyBard’s paintings – listing here. (reproduced here with permission)

  • Peeping peepers: I live on the outskirts of Montreal and over the past week, the spring peepers have been making some noise! (spring –> it’s here!)
  • Milk Cartons & Guitars: Two musical bits to wrap up.  First, I’m especially fond of bluegrass, old-time, trad., folk, indie…. My colleague and friend Elena Bennett pointed me to the “Milk Carton Kids” – what a talented duo.
  • And, to finish… talk about GEEKY!  Here’s the “Arthropod song“

“Baby you’re and arthropod. Shake that segmented bod”

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Spiders as catalysts for ecosystem development

It is well known that spiders are effective at dispersal and colonization, in part because of their ability to ‘balloon‘ – small spiders (i.e., immature specimens, or adults of species that are small) will release a strand of silk and let the wind pick them up and carry them far distances.  This passive ability to disperse has served spiders well, and enabled them to be among the first animals to colonize new habitats.  For example, after the eruption of Mount St Helens, the depopulated Pumice Plain was re-colonized over time, and biologists kept an eye on what was dropping from the skies.  Not surprising (to me!) was that spiders represented a lot of this ‘aerial plankton‘ – Crawford et al. (1995) reported that spiders represented “23% of windblown arthropod fallout and contributed 105 individuals per square meter“.

A spider about to launch! Photo by Bryan Reynolds, reproduced here with permission. Please visit his work!

A spider about to launch! Photo by Bryan Reynolds, reproduced here with permission.

Many, many people have recognized this amazing ability of spiders to get to places effectively and quickly.  During his voyages on the HMS Beagle, Darwin observed and commented on this. He noticed spiders landing on the ship when they were far offshore.  Here’s a lovely quote:

      These, glittering in the sunshine, might be compared to diverging rays of light; they were not, however, straight, but in undulations like films of silk blown by the wind.

-Charles Darwin, Voyage of the Beagle, 1832

A wonderful paper titled “Distribution of Insects, Spiders, and Mites in the Air” (Glick 1939) also discusses aerial plankton. In this work, Glick reports on how a plane was used to collect arthropods in the skies – this was done by modifying the plane so it had a collection net attached to it.  Spiders were among the most commonly collected taxa, and were found up to 15,000 ft in altitude.   Glick followed this up with work published in 1957, and spiders were again reported as common aerial plankton.

Convinced?  Spiders really are everywhere and can get anywhere – from dominating the tundra, to floating far above as tiny eight-legged aeronauts.

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This takes me (finally) to the point of this post, and some reflection about a paper by Hodkinson et al. (2001), titled “What a wonderful web they weave: spiders, nutrient capture and early ecosystem development in the high Arctic – some counter-intuitive ideas on community assembly”.  In this work, the authors provide some data about aerial plankton in a series of sites representing different stages of succession in Midtre Lovénbreen – a ‘small valley’ glacier in Spitsbergen (a Norwegian high Arctic Island).   This forum paper was meant to present an idea about ecosystem development in the Arctic, with a focus on spiders and other aerial plankton and their relationship to nutrients.

  • Spiders are among the first to arrive due to their amazing abilities at dispersal and colonization.
  • Many spiders will just die, and their sad, little bodies will decompose and leave behind nutrients.
  • Many of the spider species that arrive will build webs, and the silk contains many nutrients. Regardless of whether the silk successfully captures prey, the silk will eventually be a hot-spot of nutrients.
  • A lot of other aerial plankton will hit these webs – this will include other arthropods (Hodkinson et al. rightfully point out the importance of Chironomids, or midges, as key prey for spiders in the north) and these prey may or may not be eaten by spiders.  The aerial plankton also includes other ‘debris’ that would be floating around (fungal spores, dirt, etc).  The webs capture all these goodies, and act as a concentrated area for a growing soup of nutrients.
  • The spider webs will collect moisture.  In Arctic systems, dry polar-deserts, and many other newly created habitats, the accumulation of moisture is rather essential for continued ecosystem development.

Taken together, Hodkinson et al. (2001) argue that spiders and their webs represent little pockets of concentrated nutrients in landscapes that are void of much other life.  These hotspots could be catalysts for ecosystem development in systems that are starting from scratch.  I really like this idea – not only does is stir up the imagination (little spiders gently falling from the sky, landing on habitat never before touched by animals, and providing the start of an ecosystem…), it really makes some biological sense.  Ecosystem development requires nutrients and substrates – of course, these would both be available without spiders, but our eight-legged friends are helping move things a long a little more quickly.

The paper by Hodkinson et al. has been cited less than I would have expected.   Although they don’t provide any experimental data, their ideas are interesting and relevant and should be studied in detail. Recently, a few papers have come out that are taking the ideas to the next level.  Konig et al. (2011) studied arthropods of glacier foregrounds in the Alps. They found that although Collembola and other ‘decomposers’ are quite important in early successional stages, overall, generalist predators (including spiders) were dominant and using stable isotope analyses, they showed that these generalist predators often ate each other – an interaction known as intraguild predation.

I often discuss Hodkinson et al.’s (2001) paper in lectures, and invariably I get the question “If spiders are first to arrive, what do they eat?“. I typically answer that spiders eat other spiders, and it’s reassuring to see literature that supports this claim.  In turn, intraguild predation itself contributes further to the accumulation of nutrients (more sad, little spider bodies littering the landscape…).

Placing this work in a more general framework, these ideas are pointing to the increased importance of predators in overall nutrient dynamics in ecosystems. I was thrilled to see a paper by Schmitz et al. (2010) that argues “predators can create heterogeneous or homogeneous nutrient distributions across natural landscapes“. Bingo. This is exactly what Hodkinson et al. were arguing – predators, such as spiders, can arrive quickly to an area, and in the context of newly formed ecosystems, may provide a hotspot for nutrients in an otherwise desolate landscape.

Although the Hodkinson et al. paper is over a decade old, it’s still relevant, and quite important. I suspect that if more newly created habitats are studied in detail, spiders will indeed prove to be catalysts for ecosystem development.

References:

Crawford, R., Sugg, P., & Edwards, J. (1995). Spider Arrival and Primary Establishment on Terrain Depopulated by Volcanic Eruption at Mount St. Helens, Washington American Midland Naturalist, 133 (1) DOI: 10.2307/2426348

Hodkinson, I., Coulson, S., Harrison, J., & Webb, N. (2001). What a wonderful web they weave: spiders, nutrient capture and early ecosystem development in the high Arctic – some counter-intuitive ideas on community assembly Oikos, 95 (2), 349-352 DOI: 10.1034/j.1600-0706.2001.950217.x

König, T., Kaufmann, R., & Scheu, S. (2011). The formation of terrestrial food webs in glacier foreland: Evidence for the pivotal role of decomposer prey and intraguild predation Pedobiologia, 54 (2), 147-152 DOI: 10.1016/j.pedobi.2010.12.004

Schmitz, O., Hawlena, D., & Trussell, G. (2010). Predator control of ecosystem nutrient dynamics Ecology Letters, 13 (10), 1199-1209 DOI: 10.1111/j.1461-0248.2010.01511.x

ResearchBlogging.org

A special thanks to Bryan Reynolds for permission to use his photograph of the dispersing Pisaurid spider.  Please visit his work here.

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Ten fun facts about Daddy Longlegs

Animals with many names: Harvestmen, Daddy longlegs, Shepherd Spiders, Grandfather Greybeard, Phalangids, Opiliones.

Cousins of other Arachnids, but an Order all to their own.   Over the past 11 months, I’ve been on a journal of discovery about these amazing creatures.

After nearly 300 tweets, and over 600 pages of text in Pinto-da-Rocha et al.’s book on Harvestmen, the Opiliones Project (in the way it was originally conceived) is over.  To recap – this was a twitter-based project in which I shared content from that weighty textbook with anyone who cared to follow along (using the hashtag #OpilionesProject).  Many folks followed along, notably my twitter friends Derek Hennen, Jaden Walker, Matthew Cobb, and many, many others…

A lovely Harvestmen - photo by B. Valentine, reproduced here with permission

A lovely Harvestmen – photo by B. Valentine, reproduced here with permission

I learned a lot along the way – and will take this opportunity to highlight ten fun facts about Harvestmen – all of these were part of the Opiliones Project.

Did you know that…

1. Salvador Dali featured Harvestmen in his work!  It’s true – check it out: “Daddy Longlegs of the Evening”

2. Harvestmen can breath through their legs!  Spiracles in harvestmen are located just posterior to the coxae of the 4th pair of legs and this supply of oxygen to Harvestmen legs (e.g., after they are removed) contributes to the duration of twitching

3. Harvestmen have been around for at least 400 million years!  Phenominal!  And Harvestmen from the Rynie chert have an extensive tracheal system – the oldest record of such tubes of ANY arthropod

4. Harvestmen are NOT venomous! They don’t have venom glands!  A common urban myth.

5. Over 60 chemical compounds have been isolated from Harvestmen secretions (e.g., the secretions that are often used in chemical defense)

6.  At least a dozen species of Harvestmen are known to be parthenogenetic (females lay eggs that produce only females)!

7.  Harvestmen often show aggregation behavior, and the largest aggregation recorded is 70,000 individuals on a candelabrum cactus!

8. Unlike other Arachnids, Harvestmen males have a penis!

9. In some Harvestmen species, males use their chelicerae to offer oral secretion to female – a type of nuptial gift!

10. In some species, Harvestment moult even after they are have reached adulthood!

So there you have it.  Many fascinating and fun facts about Harvestmen (and there are many, many more) – you can access all the tweets from the Opiliones Project here (all 24 pages of them).

There were some other notable Harvestmen events over the past year, and it was fortunate this project coincided with these events.  For example, the Taxonomy Hulk burst onto the scene, and highlighted an article depicting a mix-up between a spider and a Harvestmen (a common mistake…).  Also, a truly HUGE harvestmen species was discovered – this sucker had a 13 inch legspan.  As May Berenbaum said over twitter…that’s a Daddy Loooooonglegs!

So, to finish – a big THANK YOU to everyone who followed along.  I hope this project was a fun for you as it was for me.

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Another lovely Harvestmen, photo by B. Valentine, reproduced here with permission.

A special thanks to Brian Valentine for permission to use his Harvestmen photos on this blog!

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The greatness of pseudoscorpions

As you know, I’m quite passionate about Arachnology, from spiders, to harvestmen and Pseudoscorpions.  These are all some of the creatures that fall into the category of the ‘obscure and amazing‘.  On the topic of pseudoscorpions, a few very fun and interesting things have happened recently, and enough to warrant a short blog post.  I also promised that I would post a few more videos related to some research activities on the hunt for pseudoscorpions in the Yukon.

1. Just look at this SEM of a pseudoscorpion!

A little while ago, my Arachnid friends and colleagues from Alberta, Heather Proctor and Dave Walter, forwarded me a stunning image of a pseudoscorpion taken with a scanning electron microscope (SEM).  Dave was kind enough to give me permission to share it here:

SEM of a pseudoscorpion (Chernetidae) - copyright D. Walter (reproduced here with permission)

SEM of a pseudoscorpion (Chernetidae) – copyright D. Walter (reproduced here with permission)

There really is something lovely about getting up close and personal with these little Arachnids. I don’t know this species, but it’s definitely in the family Chernetidae – a relatively diverse family, quite common across Canada.  My favourite Yukon species, Wyochernes asiaticus, is also a Chernetid.   Dave Walter really does some magic with his SEM images, and you are encouraged to check out is macromite blog (his home bug garden blog is also worth a peek!).

2.  Just look at these videos about collecting pseudoscropions in the wild! 

Speaking of my favourite Yukon species, I took a lot of videos of field work in the Yukon last summer and I wanted to share a few with you, here.  Although our larger purpose for the trip was to complete some follow-up field work for the Northern Biodiversity Program, I also wanted to collect additional specimens of a wonderful pseudoscorpion species.  The first video provides some context to the work, and gives you a bit of a flavour of the landscape up near the Yukon – Northwest Territory border in Canada:

Typically, pseudoscorpions are not that commonly encountered.  In my experience, when they are encountered, you tend to see one or two.  What is truly amazing is the sheer abundance of this species found under rocks in creek/river beds in the Yukon.  Furthermore, you can see and collect multiple life stages, including females with eggs.  This short video gives a taste for this abundance.

The third and final video is a big goofy, and highlight the ‘collecting gear’ and appropriate field attire for becoming a “pseudoscorpion hunter“.  I am continually on a crusade to help generate enthusiasm for Arachnids, whether it is dispelling myths, or trying to inspire others to become Arachnologists (you know, we do need Arachnologists in Canada!).

One important caveat:  you may NOT simply run to the Yukon and flip rocks to collect pseudoscorpions – many parts of the world, including the Yukon, have strict guidelines about what you can collect.  Permits are required, and be sure to check into this before you plan on becoming an Arachnologist!

3.  Just look at this pseudoscorpion necklace!

To further illustrate my rather quirky obsession, I managed to find a wonderful person on Etsy who was able to make me a pendant with a pseudoscorpion design:

The pseudoscorpion necklace. You want one.

The pseudoscorpion necklace. You want one.

Not only that, this design is actually from a photography I took a few years ago, and is an accurate depiction of the cosmopoliton species Chelifer cancroides.

Chelifer cancroides - my photo which was used to design the pendant

Chelifer cancroides – my photo which was used to design the pendant

I KNOW you want to get yourself one of these… start a conversation with Lynn.  Get yourself one of these necklaces and stand proud with other pseudoscorpionologists!

In sum, I do hope you find this post interesting, hopefully fun, and has whetted your appetite from more information about curious critters.

Stay tuned… I will continue to post more about Arachnids…

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Where are all the Arachnologists? (and why you should care)

Canada is a big country, with an amazing diversity of habitats, from the temperate rainforests of Vancouver Island, to the polar deserts on Ellesmere Island.  We are a country that harbours thousands of Arachnid species (yes, our eight-legged friends!).  Some examples: the Yukon Territory hosts over 300 spider species and over 150 species of Oribatid mites; Quebec is home to well over 600 spider species.  The Alberta Biodiversity Monitoring Institute has documented over 200 species of Sarcoptiformes mites from a relatively few number of sites in Alberta, and their work is far from complete.  The Canadian National Collection of Insects and Arachnids in Ottawa has one of the best spider and mite collections, world-wide.

A beautiful jumping spider. Photo by C. Ernst, reproduced here with permission.

A beautiful jumping spider. Photo by C. Ernst, reproduced here with permission.

The general public is fascinating by Arachnids: my post titled ‘Spiders do Not Bite‘ continues to get hundreds of hits every week.  We link comic-books and superheroes to Arachnids (even if the anatomy of spiderman is all wrong…).  Spider silk is used to make dresses, violin strings, and has potential in pest control.  There are invasive spider species that go unnoticed, yet may affect native species – as Bednarski, et al (2010) have documented in Maine.  Spiders continually show up in grocery stores and cause alarm and fear (although mostly not warranted..).  People are often picking ticks off their pets, or hearing about lyme disease.

Everyone has a story to share about Arachnids.

Recently, the Class Arachnida was a lunchtime topic of discussion in the lab. This discussion was in part prompted by an email I received from Leslie Brunetta. She asked the question about how we can promote Arachnology in University education.  One way to do this would be for Arachnologists to agree to deliver guest lectures in organismal biology classes, and this got us into a discussion about how many people get paid to work on Arachnology in Canada.

I tried to estimate the number of people in Canada who spend a significant portion of their time getting paid to do things with Arachnids – and I consulted a lot of colleagues to get this done.  This would include academics with a research focus on Arachnids (from behavioural ecology to biodiversity science), and government scientists working on Arachnids (from systematics through to the use of mites as biological control agents).  This does not include graduate students, nor does it include people working on short-term contracts.  I estimate that fewer than 20 people are paid to work on Arachnids in this country. This is truly astounding and astonishing.  Arachnids include two Orders that are among the most diverse on the planet: combining the Acari (mites & ticks) and Araneae (spiders) gives you estimates of well over 85,000 described species, globally.  There are only a handful of Insect Orders that are higher.

Let’s revisit why EVERYONE should care about Arachnids and why Canada ought to have more Arachnologists: 

Spiders are key predators in agroecosystems (the classic paper by Riechert & Lockley 1984 is quite relevant!). Spiders eat mosquitoes, including those that can be vectors for malaria (Nelson & Jackson 2006) .  Spiders are key prey for highly valued vertebrates (Gunnarsson 2007).  Spiders can be medically important – their venom has remarkable potential for drug development (Rates et al. 2011).

Mites are everywhere – they play critical roles in decomposition of organic matter (Kampichler & Bruckner 2009). Plant-feeding mites are economically important for dozens of crops.  Follicle mites are in our heads (Elston 2010).

Ticks can transmit diseases that are very important for human health and well being (Sperling & Sperling 2012). Ticks can hurt our beloved pets (Blagburn & Dryden 2009).  Ticks can be harmful for wildlife populations (Addison et al. 1994).

Need more convincing?

Arachnids are stunningly beautiful; they are among the ‘small and obscure’ creatures most worthy of study. In addition to mites, ticks and spiders, we can’t forget about Opiliones, Pseudoscorpiones, Scorpiones and other Orders… Arachnids should adored as much as Pandas, or the Mona Lisa.

8 Oribatid mites scaled to a 12 pt Times Roman period (0.5 mm dia.). Photo by D. Walter, reproduced here, with permission. You should visit his blog.

8 Oribatid mites scaled to a 12 pt Times Roman period (0.5 mm dia.). Photo by D. Walter, reproduced here, with permission. You should visit his blog.

CANADA: THIS IS A CRISIS!  We must find a way to ensure Arachnologists get paid to do Arachnology in Canada.  The most obvious place to point is the CNC.  It is unacceptable that a spider taxonomists has yet to be hired to maintain that spider collection.  We should be embarrassed.  Taxonomists are needed in Canada, especially for dominant arthropod groups.  The Canadian Council of Academics makes this point quite clearly in their report on Canadian Taxonomy:

     Job openings in taxonomy have virtually ceased and research funding is stagnant.  Canada’s international contribution to new species descriptions has fallen from 6th in the 1980s to 14th in the 2000s. 

Oh Canada. Where are your Arachnologists?

Oh Canada. Where are your Arachnologists?

I realize that many other taxonomic groups remain understudied – However, I am discussing an entire Class of animals!  Could you imagine if I were discussing Mammalia, or Reptilia, or Insecta?  There would be an uproar.

Let us work to fix this.  Let’s train excellent Arachnology graduate students, let’s lobby Departmental Chair, Deans, Bureaucrats in Government, members of Parliament, and whoever else will listen.  MUST Listen.

Our eight-legged friends need our help.

References

Addison, E., McLaughlin, R., & Broadfoot, J. (1994). Growth of moose calves infested and uninfested with winter ticks Canadian Journal of Zoology, 72 (8), 1469-1476 DOI: 10.1139/z94-194

Blagburn BL, & Dryden MW (2009). Biology, treatment, and control of flea and tick infestations. The Veterinary clinics of North America. Small animal practice, 39 (6) PMID: 19932369

Danks VH and JA Downes. 1997. Insects of the Yukon. Biological Survey of Canada.

Gunnarsson, B. (2007). Bird Predation On Spiders: Ecological Mechanisms And Evolutionary Consequences Journal of Arachnology, 35 (3), 509-529 DOI: 10.1636/RT07-64.1

Elston, D. (2010). Demodex mites: Facts and controversies Clinics in Dermatology, 28 (5), 502-504 DOI: 10.1016/j.clindermatol.2010.03.006

Kampichler, C., & Bruckner, A. (2009). The role of microarthropods in terrestrial decomposition: a meta-analysis of 40 years of litterbag studies Biological Reviews, 84 (3), 375-389 DOI: 10.1111/j.1469-185X.2009.00078.x

Nelson, X., & Jackson, R. (2006). A Predator from East Africa that Chooses Malaria Vectors as Preferred Prey PLoS ONE, 1 (1) DOI: 10.1371/journal.pone.0000132

Rates B, Verano-Braga T, Santos DM, Nunes KP, Pimenta AM, & De Lima ME (2011). From the stretcher to the pharmacy’s shelf: drug leads from medically important brazilian venomous arachnid species. Inflammation & allergy drug targets, 10 (5), 411-9 PMID: 21824079

Paquin, P.  &  N. Dupérré 2006. The spiders of Québec: update, additions and corrections. Zootaxa 1133: 1-37.

Riechert, S., & Lockley, T. (1984). Spiders as Biological Control Agents Annual Review of Entomology, 29 (1), 299-320 DOI: 10.1146/annurev.en.29.010184.001503

Sperling, J., & Sperling, F. (2012). Lyme borreliosis in Canada: biological diversity and diagnostic complexity from an entomological perspective The Canadian Entomologist, 141 (06), 521-549 DOI: 10.4039/n08-CPA04

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