How to ID a jumping spider

While the topic has been talked about obliquely, it seems time we came out and said it directly.  How, exactly, do you know if you have found a jumping spider or not?  The easiest way it to simply look at its eye arrangement.  If it is a jumping spider, it will have two very large eyes in the center of its face, flanked by another slightly small pair.  The picture below is an excellent example of a male Phidippus audax.

http://en.wikipedia.org/wiki/File:Phidippus_audax_male.jpg

 However, if you prefer not to get quite that close or lack a hand lens to help you see the eyes, we have hammered out a few rough rules below that should allow you to ID them anyways. 


DISCLAIMER: These rules are guidelines only!  Like much of science, there will be exceptions to rules such as these, no matter how carefully crafted.  Please also keep in mind that these rules, while very general, are also focused mainly on the salticids of North America.  The tropics will have exceptions to most, if not all, of these rules.


Rule 1: Where was the spider found?
    a) On the ground - Maybe a salticid, see rule 2
    b) On a vertical surface like a wall - Maybe a salticid, see rule 3
    c) In a web -  probably not a salticid, but see rule 4

Rule 2: When you walk up to it, how does it move?
    a) Jumps! - probably a salticid
    b) Runs away very fast - most likely not a salticid

Rule 3: If you wave your hand near/over it, what does it do?
    a) Turns to face your hand, or where your hand came from - Salticid!
    b) Runs like heck! - probably not a salticid

Rule 4: What is the spider doing in the web?
    a) Building the web - NOT a salticid
    b) Feeding on another spider -  Maybe a salticid, see rule 5.

Rule 5: What do the legs look like?
    a) Very long and spindly - Not a jumper
    b) Proportional to the body size - probably a salticid

Rule 6: If capture and put in a container (NOT airtight!) for a day or two, what does it do?
    a) Builds a tiny silken sleeping bag - Salticid!
    b) Builds a traditional web - not a salticid
    c) Stays on the bottom of the container and cannot seem to climb the walls - not a salticid


If you think you have found a jumping spider, we encourage you to Google the animal's description.  As jumping spiders are so very colorful, and often uniquely patterned, you can often find the specimen your looking for without too much trouble. One great resource for this type of searching is Bugguide.net.

Just remember, that when in doubt, always err on the side of caution and contact an expert to help you identify the spider. 

New year, New start!

The last few weeks have been rather slow in terms of posting.  Jon and I apologize for this unexpected silence on our end. November and December became inundated with unexpected events and experiments.  However, as the new year starts, new schedules are taking shape and many good things are on the way! 
     The good news for you dear readers is that this coming semester will feature at least one new blog post a week starting around the middle of January.  Why the sudden increase in posting?  Well, long story short, the book the we have been mentioning has been moved off of the back burner and will be getting large amounts of attention this semester.  This means that not only will new pictures be posted frequently, but also that previews of the book's contents will begin showing up on our blog!
     Jon and I are both very excited about these new developments and look forward to hearing what you, dear reader, think and things progress!

Happy New year!

Miniature Mating Rituals

     Imagine a world where your everyday is fraught with danger.  Danger from predators hundreds of times your size.  Danger from your potential food which might try and eat you back, or if you're lucky, is only poisonous.  Imagine a world so dangerous, that even trying to ask a pretty girl out for a bite to eat could result in you being what was eaten.  If you can do all this, then you are starting to understand the world of a jumping spider male on the quest for a mate...

     Jumping spiders have some of the most elaborate and complex mating rituals in the arthropod world.  There are a some really good theories behind this complexity, and in today's post we will discuss a few of them.
     Many male spiders use vibration as a signal when courting an attractive female, and jumping spiders are no exception.  However, unlike many spiders, salticids also have very elaborate visual displays to accompany their vibratory signalling.  When you combine the visual display (signal) and the vibratory display (know as a seismic signal in the scientific community), you end up with what is called a multi-modal signal.  In other words, if you (the signaler) emit a signal over multiple sensory channels (seismic + visual in this case) you can potential provide more information in less time to the listener (receiver).  For instance, the seismic signal could say one thing (ex: I'm a male of your species), while the visual signal could say something else (ex: I'm really fit and attractive!).  However, the cost of sending signals this way include things like increased complexity of the transmission, which also increases the difficulty of sending this signal without making an error.  This idea of increased difficulty is one of the ideas behind a jumping spiders multi-modal courtship.  By using a more complex and difficult to produce signal, the male spider can potentially increase his attractiveness to the female by demonstrating how much more fit he is than his competitors.  To put it in more human terms, think of it as having to choose between a mate who can do push-ups while doing basic arithmatic (ex: 2+2=4) in his head versus a mate who can do as more pushups while also doing calculus (ex: d/dx tan x = sec² x) in his head.  Pretty easy choice right?

     Another idea (the signal redundancy hypothesis) asserts that these multi-modal signals are not sending multiple pieces of information, but rather the same information two different ways.  The idea here is that if one signal is blocked or poorly received, for instance because the light is poor, then the second part of the signal can compensate for the deficiency. This theory makes a lot of sense when you consider the environments in which some of these spiders live.  Tropical forests, for example, have a patchy light distribution and so a spider may not always be able to signal in the lighting that makes him look best.  In this case, he would rely on the seismic signal to help him impress the ladies.  While he would probably give the best impression in bright light and a nice seismically conductive surface, the males have adapted to being able to signal even under less than ideal conditions.  After all, when the consequences of not impressing a female on the first try include death, you don't want to mess things up when you do find the elusive mate you've been hunting.

Enough with theory, how about some practice?  The video below is an excellent example of multi-modal courtship.  What you will be watching is a male spider courting a female spider.  The female is the one who is pinned in place with wax, while the male is the one moving around and making all of the buzzing and revving sounds.  It does take the male about 30 seconds to really get going, but once he does, he puts on quite the show!

Please click here for a non-embedded version.

For other examples of salticid courtship, I highly recommend searching youtube for "Jumping spider courtship," there is some amazing footage and even a few amusing remixes on the site.

Happy spidering!

I am Arachnophobic

    Hello, my name is Jon and I am arachnophobic. When I mention that I work with spiders and am arachnophobic many people question how it works. I myself sometimes question how I manage it and why my arachnophobia excludes Salticids. It wasn't always that way; any and all spiders got swift “justice” underneath my foot or beneath a rolled up magazine or newspaper.

 

My slow transformation from complete arachnophobia to working with spiders began sophomore year of college in an Introduction to Zoology class.

   Matt was looking for a student volunteer to help him with his research, somehow I volunteered. My first trip into the field with Matt was an icy shock into the world of spiders. Matt had set up a grid system of marking flags with small vials turned upside down taped to them. The idea is that Salticids, which don't build webs but instead make nests, would use the vials as substrate for their nests and we would come along and coax the spiders out of them. So around dusk, Matt and I arrived at our first set of traps. Matt calmly showed me what we were doing and then let me at it. I will admit, I was deathly frightened that the salticids would jump out and attack me as soon as I turned the flags upside down to tease them out, but I slowly realized that this was mental overreaction. After enduring two months of this “torture” I was finally coming to appreciate the creatures I was collecting.

   Once winter had set in, I was then tasked with identifying what we had collected. Little did I know how much identification I would be doing over the next three years! The dichotomous key was difficult to understand at first as most of the terms were completely new to me (have no fear, we'll make ours easy to understand as you'll see below). Much of my time was spent looking up what the labium was and if it was wider then the sternum or not or trying to keep the names and order of the eyes straight.

Lateral view of Salticid eye locations

   But slowly I became familiar with the key and soon was able to locate multiple morphological features that I would need during my initial inspection of the specimen. From that point on, I rapidly learned the frustrations of working with specimens that were tiny, some only a few millimeters. Trying to tease the chelicerae and fangs open to see if and how many retromarginal teeth were present, is the PME closer to the ALE or PLE, is patella-tibia 3 longer or shorter then patella-tibia 4, how many macrosetae are on tibia 1?

Found on an immature Marpissa.  PS: There are only supposed to be eight macrosetae! (Photo by Jonathan Knudsen)

It was during the first year of identifying that I discovered the two steps that I hated the most: Step 33 and Step 58. These are two steps that require the specimen to be sexually mature, and both involve the shapes and structures of the embolus and epigynum.

   As we begin work on the key for our guide, one of our main goals is to make it easy to understand and use. Instead of using technical jargon and details about each spider, we plan on using easier to see morphological traits and terms to key each species out. In a true dichotomous key, each species keys out in only one place. However, because we plan on taking a broader view of each species, multiple species may key out the same. This may seem like a problem, but we think it will be easier to say, “It may be Spider A (pg. XX), Spider B (pg. XX), or Spider C (pg. XX)” and then comparing our photos to their specimens to make the final species identification. Many of the specimens we've collected are fairly unique looking, so any confusion during the keying process can be sorted out using our photos.

   I have enjoyed being a contributor to this guide and now to this blog. I look forward to continuing our work on this project and keeping you updated as we progress. It has been a fun challenge so far and it will continue to be. Keep you AME's peeled for my next posting!

Spotlight on the genus Phidippus

   Our spotlight genus this go round is the loveable and charismatic Phidippus.  This genus is one of the more commonly photographed jumping spiders due to their large size (1cm or larger is not uncommon), often ornate coloration, and generally curious disposition.  

Phidippus mystaceus "Is something moving over there?  Let's go Look!"

 The Phidippus genus encompasses at least 60 different species, including several that are often used in behavioral studies.  For example, my research primarily focuses on the foraging and learning behaviors of Phidippus audax.  

Phidippus audax from Bugguide.net

 Other commonly studied species include P. clarus, P. johnsoni, and P. princeps.  While most of the work on this genus consists of natural history descriptions out of Dr. Robert Jackson's lab,  much of the more recent work has been conducted by Dr. Beth Jakob’s lab where the focus is on vision and visual processing. 

Phidippus clarus from Wikipedia.org

Phidippus johnsoni  from Wikipedia.org

Phidippus princeps from Bugguide.net

  

Phidippus are unusually bulky for salticids, giving them the appearance of being rather short-legged.  Unlike some of their more slender cousins, Phidippus often remind me of tiny tanks when they are cruising around in search of a prey item.  While they are still quite capable of pouncing on potential prey items, they tend to do so from a distance of only 1-2 body lengths, rather than the 4+ body lengths a Habronattus or Lysomannes might jump.  

Habronattus agilis from Bugguide.net

One of the defining features of Phidippus are their iridescent chelicerae.  This unique character makes field identification of this genus considerably easier than some of their more cryptic cousins.  In addition to aiding in id, they are also very colorful and can be red, orange, green, blue, and even purple!

Phidippus audax chelicerae by Thomas Shahan

Like virtually all salticids, they are cursorial (wandering hunters) and do not spin webs for prey capture.  As such, you may catch a glimpse of these tiny predators on the hunt.  As Robert Jackson says, the often look like “tiny eight-legged cats” when on the prowl.

Finally, if you see one of these spiders, I highly recommend you take a minute or two and watch their behaviors; they could even be watching you!

Happy watching!

Salticids... in Space?!?

While that may sound like the title to yet another cheesy spider horror movie, it is in fact a real thing.  Thanks to NASA's "You Tube Space Lab" program, a very curious young man by the name of Amr Mohamed was given the opportunity to send Salticus scenicus into space.  The video to below was his entry into the contest and briefly outlines his experiment.

As you can see, he does pose quite an interesting problem.  While I have my own ideas on how they will adapt, I am curious about your thoughts, dear reader.  Do you think the spider will be able to hunt successfully in a Zero-G environment?  Why or why not?  I would absolutely love to hear your comments and thoughts in the comment box below.  Finally, if you want to find out what happens, a live stream of the experiment will be broadcast this Thursday September 12 at 0950 (ECT).

For a full write up on this project and the other winning entries, please go to http://www.nasa.gov/mission_pages/station/research/news/livestream.html

And the spider marches on...

Dear readers,

In spite of the lack of regular (or otherwise) updates lately, we here at Yours for 8 Eyes are not in fact dead.  What we are though, is incredibly busy.  Two weeks ago I (Matt) and a soon to be new contributor (Jon) went to Cedar Point Biological Station in Ogallala, NE for a little collecting trip.  What we ended up with instead was Matt and Jon's Wild Spidery Ride.  Instead of bring back between 100-150 salticids as we had hope, we picked up nearly that many on our second day!  We even had some days where we were only able to collect for part of the day due to the weather, but still collected more than 100 specimens that day.  Long story short, we ended up returning with ~400 live salticids and several more preserved specimens.

Each row of vials represents a "new" species found at CPBS.

I can hear you thinking, dear reader, "what does this have to do with you and why haven't you been posting more anyways?"  Well, what this has to do with you is that our booklet (mentioned in earlier posts) will now contain more than 40 species of salticid from Nebraska and should be rife with beautiful color pictures of all of the specimens.  As for the lack of posting, lets just say 400 salticids is more than double the amount we've ever had alive in the lab and is turning out to be a ton of work.  Thankfully, we enjoy the work!

Salticus scenicus, an incredibly common species we encountered  at CPBS.

So what's to come then?  Well, the short term plan is to keep posting, hopefully on a weekly basis.  The longer term plan includes getting that booklet done and published, continuing to pursue arachnological outreach through this blog and in person, and even graduating!  It's going to be a busy little while, but stick with us and some exciting things should appear here shortly.