Photo of the Week – September 13, 2018

Hello from Wisconsin!  I’m spending this week in Madison, Wisconsin with about 250 colleagues at a conference for scientists, land managers, and other conservation staff of The Nature Conservancy.  It’s been a fantastic conference, but also an awful lot of time spent with crowds of people – something that drains me after a while.  As I write this, I’m holed up in my hotel room, grabbing a little peace and quiet before heading to supper.

On Tuesday, I went on a great tour of prairies in the Military Ridge Prairie Heritage Area.  It’s a great site with a lot of 

Because I’ve been busy with the conference all week, I haven’t done much photography (and I really miss my square meter plot!) but I did manage a few photos during our Tuesday field trip west of Madison.  We had a few minutes to wander after arriving at our first stop, and I stopped to admire numerous Argiope spiders on their webs.  Even after our tour leader started talking, I wandered around the edge of the group – staying within earshot – and looked at some more spiders.  I hope I didn’t come off as rude, but the spiders were really pretty, and a few let me get within photo range.

This big female banded argiope (Argiope trifasciata) spider was feeding on an undetermined insect.
This little male Argiope spider was lurking at the edge of a female’s web, hoping to entice her to mate with him, rather than to kill and eat him.  I wish him luck.
I don’t know what species this is, but this small orb weaver spider was working to wrap and eat a leaf hopper.
After I took the previous photo, the spider suddenly noticed me and scurried up to the top corner of its web and hid itself beneath a little canopy.

Not long after I took these photos, the sunlight became too intense for good close up photos so I rejoined the tour group and behaved myself.  There is great conservation work going on in the Military Ridge area, with a great set of partners working together.  It is one of the best remaining landscapes in Wisconsin for grassland birds, and still has fairly stable populations of regal fritillary butterflies and other species.  Eric Mark with The Nature Conservancy is doing some grazing work to manage bird and butterfly habitat, and is working hard to build ties with the local community.  The local chapter of The Prairie Enthusiasts is doing some tremendous prairie restoration work, converting brome fields to diverse prairies.  Those and other partners, including state, federal, and non-profit organizations, seem to have a strong and positive working relationship.

Oh, and there are some pretty cool spiders too.

Photo of the Week – August 24, 2018

Former Hubbard Fellow Evan Barrientos came back for a visit last week and the two of us wandered around with our cameras for a couple hours on a wet foggy Saturday morning. (Quick reminder – applications for the next round of Hubbard Fellows are being accepted NOW – click here for more information.)

It was a beautiful morning, and we spent the bulk of our time in a prairie Evan had helped create while he was working for us.  Despite its young age (3rd growing season), the prairie already has a lot going on.  Plant diversity is looking good and invertebrates seem to be colonizing nicely.  Among those colonizers are a lot of spiders, and a foggy morning is a great time to see and photograph spider webs.  I spotted webs of several different species, but ended up photographing mostly webs created by a couple different species of (I think) longjawed orb weavers (Tetragnatha sp.).  I photographed much more than just spiders during those couple hours, but some of the longjawed orbweaver shots ended up being my favorite images of the day.

A longjawed orb weaver sits poised on its dew drop covered web, warming itself in the sun.
Early morning diffused light beautifully accented both spiders and their webs.
This is the same individual as in the first photo above, but from the other side of its web.  The spider was being very patient with me – and I was being very slow and deliberate in my approach to it.

The following three photos were taken within a minute or so of each other.  I couldn’t decide between them, so have included all of them.  I’m curious to know if any of you have strong preferences between them.  I think I like the first and third best, though the second is really nice too.  See what I mean?

Spider 1

The pose of this spider is common among many skinny long-legged spiders.  When inactive, or in the presence of a potential threat, they cozy up to a grass leaf or plant stem and almost seem to melt into it.  This one was in its hiding pose when I first spotted it. Judging by the dew droplets still affixed to its legs, I’m guessing it spent the night in that pose, but I’m not sure.

Between the first and second photo, I carefully held out my hand near the web and the spider shifted slightly away from it, moving a little more toward my camera, and into the light.  This is a really handy trick for slightly repositioning insects and other invertebrates for photos.  It always works spectacularly, except when it fails even more spectacularly and the subject hops, drops, or otherwise flees.

Spider 2

As I was photographing the spider in its new, more illuminated position, it suddenly stretched out its legs – as if it was yawning.  I squeezed off a couple quick shots before it returned to its original position.

Spider 3

The chance to photograph spiders on dew-covered webs always feels like a gift.  The conditions have to be just right – including near-zero wind velocity.  Late summer seems to be the time when an abundance of spider webs corresponds with an abundance of calm foggy/dewy mornings.  On those mornings, I tread carefully through prairies, trying hard not to blunder through webs, but knowing I will anyway.  I find most webs by looking toward the sunlight so that the glowing backlit dew-covered orbs stand out against a darker background.

Most webs are close to the ground, surrounded by tall vegetation, making them nearly impossible to approach without jiggling the web, and either breaking it or scaring the spider away – or both.  To add to the difficulty, most spiders sit on the downward slanting side of their web, with their eyes facing down and away from the sun. I always like to feature the faces of invertebrates when I can, but it’s not always possible to find a camera angle that works with web-weaving spiders.

The first three photos above were taken of webs that were along a restored wetland swale, where vegetation was relatively thin and I could fairly easily slide my tripod close to the spiders.  The last three were of a web that was placed at nearly head height – something I don’t see very often.

Oh, I did take photos of Evan too, but he wasn’t covered in dew and sitting on a glistening orb-shaped web, so he didn’t make the cut for this blog post.

Photo of the Week – April 20, 2018

The prairie is finally waking up (again) around here.  Before last weekend’s blizzard weather, plants were starting to green up, but all that stopped for a while last weekend so we could enjoy one last (?) snowstorm.  We didn’t end up with much accumulation on the Platte River, but our Niobrara Valley Preserve got over a foot of snow.  Yesterday afternoon, the sun was warm and bright along the Platte, so I took a few hours to enjoy the latest reboot of spring.

This tiny orb weaver spider was starting a web in a recently burned patch of prairie. The grass was only a few inches tall, but the spider was using the breeze to string silk between the young shoots. I laid on my belly for quite a while and watched it work.
I’m not sure if it finally noticed me or just needed a rest, but after working for quite a while, the spider retreated to this little hiding place. I waited for several minutes, but it apparently wasn’t going to keep working, so I left it alone.
I noticed this open hole in a fresh pocket gopher mound and thought maybe I’d catch the gopher bringing a load of dirt out of its tunnel. I sat quietly near the hole for a few minutes until I looked more closely and decided it didn’t look as fresh as I’d first thought. I don’t think anything had disturbed the soil at the mouth of the hole since the snow melted. Pretending not to feel foolish, I moved on…
This roundheaded bushclover (Lespdeza capitata) leaf had what I think were probably fungal spots on it. While it wasn’t fresh green growth, I thought it was interesting and attractive enough to be photographed.
While it doesn’t look like much, the yellow-flowered sun sedge (Carex heliophila) shown here was my most exciting discovery of the day. We can’t get it to establish from seed, so we’d moved some plants from a nearby remnant into this restored prairie back in 2011.  Since then we hadn’t been able to find any (tiny plants under tall grass). Since the plants were blooming yesterday, I went looking in an area that was grazed last year and found hundreds of them! The plants survived and are spreading quickly via rhizomes.  This was the first one I found.
Dandelions (Taraxacum officinale) are playing their annual role of supporting early pollinators until native wildflowers get rolling. Yesterday was the first time I’d seen any blooming, but I saw several flies (including this one) and a honey bee already feeding from them.

It’s supposed to cool off again this weekend, but the forecast doesn’t show temperatures dropping below freezing – at least for the next week.  Maybe spring will actually catch on this time?  It’ll be interesting to watch plants like windflower (Anemone caroliniana) that started to grow and then got frozen off – multiple times.  Will they still bloom, or will they just give up and wait for next year?  Regardless, it’s sure nice to see something moving around in the prairies besides dead plant stems being blown around by the wind.  Let’s go spring!

Spider Watching

I think this is a juvenile Argiope spider.  With its legs fully spread, it was about the diameter of a quarter, and its web was about the size of my hand.

During a brief stop at our family’s prairie this morning, I noticed a small spider on its web, and set up my tripod to see if I could photograph it.  Just after I got a couple nice photos, a grasshopper nymph blundered into its web, and the spider leapt into action.  I tried to get pictures of it as it was quickly wrapping the little grasshopper, but I only managed one – it was moving quickly, and there was some vegetation in the way.

I managed to get this shot when the spider paused briefly while wrapping the grasshopper nymph. The image is a little fuzzy because I was shooting through some grass leaves, trying not to disturb the action.

However, once it had its prey stabilized, the spider slowed down and I was able to watch and photograph it for the next 10 minutes or so as it waited for the nymph to become sufficiently paralyzed.  When I finally had to leave, the spider hadn’t yet started to feed.  Instead, it was perched above the nymph with two legs resting on the nymph like it was feeling for a pulse.  Every time the nymph twitched, the spider quickly pulled its legs back as if it had touched a hot stove.  Very carefully, I pulled my tripod away and left the spider to its meal.

This was shortly after the spider finished the wrapping process. You can still see the silk attached to its spinnerets (near its rear end).
…waiting for the grasshopper to stop kicking… I assume spider got to eat it eventually, but I had to get to work.

Photo of the Week – June 8, 2017

In several of our prairies right now, poppy mallows are among the most prolific flowers.  Purple poppy mallow (Callirhoe involucrata) and pale pink poppy mallow (Callirhoe alcoides) are not only great tongue twisters, but also pretty flowers and important food sources for pollinators.  Earlier this week, I watched a monarch moving from flower to flower in a big patch of pale pink poppy mallow, but I didn’t manage to get a picture of it.  Yesterday, I paused to photograph a poppy mallow blossom and noticed something funny about the underside of the flower…

Those of you who have followed the blog for a while know of my affinity for crab spiders.  They’re just so stinking cute, and once you start looking for them, they are everywhere, especially on flowers.

This particular long-legged friend and his relatives were on several kinds of flowers in our prairies this week, including pale pink poppy mallow (above) and yarrow (below).

At our family prairie, I found a different crab spider (below) hanging out on yarrow with its long front legs cocked and ready to spring shut on unsuspecting prey.

As I photographed the spider, a fly landed on the flower and started feeding on pollen and moving about the flower.

It got closer and closer to the spider, so I just kept shooting.  A few moments later, it turned its back on the spider…

…and the spider GRABBED it.  The fly buzzed loudly and drug the spider around a little, but was no match for the strong grip and venomous bite.

For a few seconds, the spider stood vertically, holding tight to the fly.  Then as the fly’s struggles subsided, the crab spider repositioned itself to start feeding.

Apparently, the spot right behind the head is the best place to puncture a fly if you want to suck out its liquefied insides.  A little tip for all you fly sucker wannabes out there…

Seeing the number of flowers with crab spiders, and the ease with which this crab spider caught its prey is a reminder of how dangerous it is to be a pollinator.  Every flower is a potential source of nutritious food, but a fair number of them also host lurking crab spiders, waiting to snag careless insects.  As someone who spends a lot of time trying to photograph pollinators, I’m keenly aware of how quickly they move from flower to flower.  Of course they do – the longer they stick around each flower, the better chance something will catch and eat them!

Hubbard Fellowship Blog – Mysterious Strands of Silk

This post is written and illustrated by Katharine Hogan, one of our Hubbard Fellows.  

In November, I visited the Valentine National Wildlife Refuge on Highway 83 south of the town of Valentine. There had been a burn several weeks previously at the refuge, and I enjoyed a little time wandering around and observing the effects of the fire on the vegetation and exposed sandy soil. In patches, some brave grasses had re-sprouted in defiance of the cooling autumn temperatures. In other areas, the patchy fire had not burned hot enough to do more than singe the thicker sunflower and forb stalks, and everywhere the rodents had wasted no time in churning up the exposed sand, leaving clean, cool piles in stark contrast with the surrounding black ash from the burned vegetation.

I had only been walking around for a few minutes when I came across something that, though strange at first, eventually astonished me in its scope across the landscape. I noticed a patch of flower stalks with some threads of spider silk, strung out from stalk to stalk, not forming an actual web but nonetheless running roughly parallel, using the burned stems as support. Upon further examination, however, I realized that this was not an isolated occurrence within the burn, and that this same patterning of silk strands stretched off in both directions across acres and acres of the burned vegetation.

Although these pictures don’t and can’t really accurately represent the scope of this phenomena, I was able to capture a couple that show, if nothing else, the impressive amount of silk that had been put out for some unknown reason by, one must guess, some very industrious arachnids.

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The lighting makes it somewhat challenging to see, but the density of the webs can be best seen in the upper center of the photograph, and extends outwards from there.  Photo by Katharine Hogan.

My knowledge regarding spiders and their habits is utterly basic. I have a high appreciation for them as fascinating creatures and as ecological players, but my ongoing efforts of understanding have simply not focused on them, focusing instead on plants in part because plants don’t, you know, suddenly relocate on you for inscrutable reasons. At the time, I could only wildly guess as to what caused this phenomenon to occur. Apparently it involved a presumably large number of arachnids deciding more or less in tandem that changing location was a really good idea, but why? And what type of spiders? Were they moving towards or away from something? Was this movement related to the recent fire? What about the decreasing autumn temperatures and daylight?

I did a little digging and came up with a couple potential situations that could describe at least in part what I saw. As always, I would welcome the insights of readers of this post with a better idea of what’s going on! I would love some help in solving this web of mysteries.

This was a typical amount of webbing that had been constructed on each of the thousands of plants across the section of the burn.
This was a typical amount of silk on each of the thousands of plants across the section of the burn.

I found references to spiders of two families that sometimes exhibit tendencies that could explain silk strands such as these. Jumping spiders (family Salticidae) leave “safety lines” of silk behind them as they jump between plants; however, this does not explain the massive amount of silk, nor why it was all aligned in the same direction across the landscape.

The other possible explanation I found was with regards to spiders, not exclusively but predominantly of the genus Erigone, that, according to a 2005 article in the Bulletin of Entomological Research, will sometimes display what is called “mass ballooning”, where large numbers of spiders in tandem migrate short distances across landscapes, leaving behind “spectacular amounts of silk on the ground” (J.R. Bell et al.). The reasons for this behavior are still largely not understood, but hypothesized explanations have included sudden changes in temperature, humidity, and other factors largely dependent upon the microclimate of the population in question.

Several other studies during the 70s and 80s also supplied some evidence that the propensity of spider populations to balloon was correlated with the “predictability” or stability of their habitats. In the case of Greenstone (1982), populations that selected for habitats subject to more frequent change, e.g. open spaces near water sources, were more likely to balloon than species that favored prairie habitats. If habitat changes are positively correlated with the likelihood of a spider population ballooning, could this suggest the recent prescribed burn as a causal factor in the event whose aftermath I witnessed at the wildlife refuge?

I honestly don’t have a clue. Other interests and appreciations aside, I am very much a “plant person” and feel uncomfortable coming to any conclusions regarding a group of organisms about which I know so fabulously little. I do know, however, that the scope of the phenomena I witnessed was truly impressive, and thus I gained a little more appreciation and awareness of the unseen lives of the tiny critters around us. As always, input on the matter would be much appreciated. If any of you readers have any insights on the matter, please let us all know in the comments! Thanks!

 

Sources cited:

Bohan, David A., et al. (2005) Ballooning dispersal using silk: World fauna, phylogenies, genetics and models. Bulletin of Entomological Research 95, 69-114.

Greenstone, M.H. (1982) Ballooning frequency and habitat predictability in two wolf spider species (Lycosidae: Pardosa). Florida Entomologist 65, 83–89.

 

 

Prairie Dog Spider

Prairie dog towns are known to provide habitat for many species of plants and animals.  Some of those are attractive and/or popular wildlife species like burrowing owls and ferruginous hawks.  Others are attractive (at least to me), but maybe less popular among the general public, including prairie rattlesnakes and black widow spiders.  It’s easy to understand why rattlesnakes would appreciate the availability of burrows.  The snakes can sun themselves on the bare soil at the edge of a burrow, but quickly retreat underground to cool off or escape predation.  From the perspective of spiders, I’m sure the burrows funnel insects nicely into webs, but I’m not sure why prairie dog burrows are so attractive to black widows in particular.  I’ve spent a fair amount of time looking for invertebrates around Nebraska, but prairie dog towns are the only places I’ve ever seen black widows.

A black widow spider in an abandoned prairie dog burrow.
A southern black widow spider (Latrodectus mactans) in an abandoned prairie dog burrow.  The Nature Conservancy’s Niobrara Valley Preserve, Nebraska.  The spider, including spread legs, was only slightly larger than a nickel.

While I was up along the Niobrara River last week, I walked around a small prairie dog town hoping to find either rattlesnakes or black widows to photograph.  I didn’t find any snakes, but did find black widows in two of the first 20 or so burrows I examined.  Both had webs strung across abandoned burrows.  That makes sense, but I wonder if the spiders recognize the burrows as abandoned before they build a web?  If not, I imagine there are some pretty interesting prairie dog/spider interactions as prairie dogs burst in or out of burrows and encounter the webs.  I laughed about something similar with badgers and spiders about a month ago, but the more potent venom in black widow spiders adds an extra degree of risk to prairie dogs…  My guess is that very few, if any, prairie dogs are actually harmed by black widows (the spiders probably just try to get away and prairie dog fur seems thick enough to protect against the small fangs anyway) but I don’t know of any research that’s actually investigated that.

My camera set-up for the above spider photo.
My camera set-up for the above spider photo.

Once I found the two black widow spiders, the next challenge was figuring out how to photograph them.  The first issue was that the late afternoon sunlight was very bright and the tunnels were very dark, making the lighting conditions problematic.  A homemade collapseable diffuser (thin fabric sewed to a plastic hoop) helped cut the light intensity.  The second problem was that the angle of the webs relative to the shape of the burrow made it difficult to get the spider in focus.  I finally gave up trying to find a position from which to photograph the first spider and concentrated on the second.

However, the biggest issue was that the spiders were very tuned in to movement near the edge of the burrow and kept scurrying away into the shadows every time my head, camera, or hand moved across the opening.  The above photo took 45 minutes to obtain.  Most of that time was spent waiting for the spider to return to the web (and the light) every time I re-positioned the camera, focused, or breathed (or so it seemed).  It’s not a fantastic shot, but given the challenging situation it still feels like a kind of victory.

Photo of the Week – May 12, 2016

Being a nature photographer sometimes means I can plan trips to interesting places and spend extended periods of time focusing on nothing but photography.  More often, however, my photography comes in short opportunistic bursts in the middle of other activities.  Fortunately, my family and coworkers are (mostly) patient with me when these opportunities arise and I briefly break away from whatever we’re doing.

Spider on a foggy morning. The Nature Conservancy's Niobrara Valley Preserve, Nebraska.
Spider in foggy prairie. The Nature Conservancy’s Niobrara Valley Preserve, Nebraska.

This week, two of my coworkers and I spent a couple days at our Niobrara Valley Preserve working on some strategic planning.  Our time together was really productive, but we were in one of the most scenic places in the world with almost no time to get outside and enjoy it.  When I woke up Tuesday morning, it was foggy outside, but bright enough that the sun was just barely visible through the fog.  My two coworkers were nowhere to be seen, so I made an executive decision that it was a great time for photography and slipped out the door and up the hill to a beautiful prairie ridgetop.

This web seemed to be uninhabited except by hundreds of water droplets.
This web seemed to be uninhabited except by hundreds of water droplets.
Water droplet at the tip of a grass leaf.
A single water droplet at the tip of a grass leaf.

I spent about 20 minutes photographing spiderwebs and other dew-covered natural wonders before slipping back into our cabin, ready to resume the meeting.  Fortunately, the other two – including my boss – hadn’t started without me.  Throughout the rest of the morning, I only sighed aloud a few times as I watched the fog slowly break up over the river and bluffs just outside our cabin, and I’m pretty sure I only pointed out the beautiful photography light seven or eight times.  Other than that I was completely focused and productive…

The same spider as shown in the first photo, but from a different angle. As long as my knees were wet from the dewy grass and the spider seemed ok with my presence, I figured I'd better shoot as many angles as I could...
The same spider as shown in the first photo, but from a different angle. As long as my knees were wet from the dewy grass and the spider seemed ok with my presence, I figured I’d better shoot as many angles as I could…

Photo of the Week – April 28, 2016

During a walk in our family prairie last week, I found a spider web spanning the entrance to a badger tunnel.

Spider and web at the entrance of a badger hunting tunnel (where a badger had dug a tunnel to catch a ground squirrel or some other small creature. Helzer family prairie. nebraska.
If you look closely, you can see the spider near the top of the tunnel entrance.

When I pulled in close with my camera, the shadow behind the web and the bright sunlight on the spider contrasted beautifully.

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It might be tempting to think the spider was trying to catch a badger except for three things.  First, that would probably end badly for the spider, and natural selection usually takes care of that kind of thing.  Second, spiders often string webs across any opening that could act as a funnel for flying insects.  A badger hole makes as much sense as any other, I suppose.  Third, this wasn’t a tunnel a badger lived in, just a hole dug while a badger was hunting a ground squirrel or some other small burrowing animal.  Most badger-made tunnels are of that ilk, and if you look closely at them, you can usually see the end of the tunnel within a few feet of the surface.

I do think it’s funny to think about what might happen if a spider hung a web across the opening of an active badger home, though.  I’m imagining a badger emerging from its tunnel in the morning and then hopping around shouting “OOOH!! Ick!  Spider web on my head! Spider web on my head!!”

Photo of the Week – October 8, 2015

Ok, I know I post an awful lot of spider photos.  I have a couple good excuses.  First, I like spiders.  I just do.  Second, for whatever reason, my eyes seem to find spiders as I walk through prairies.  Third, spiders are abundant in prairies (and most other ecosystems) and they play very important roles in prairie ecology.  It seems appropriate for them to be well represented in any collection of grassland images.

Spider on web on switchgrass. Valentine National Wildlife Refuge, Nebraska.
This tiny spider made its web on the flowering head of switchgrass in the Nebraska Sandhills.  Valentine National Wildlife Refuge, Nebraska.

But mostly, I just like spiders.  I hope you do too.