Araneae

Spiders.

A truly disturbed garden spider

/ Ted C. MacRae / 15 Comments
Argiope trifasciata vibrating web in response to disturbance.

Argiope trifasciata shaking its web in response to being approached.

This past weekend I made a trip to the White River Hills region in extreme southwestern Missouri. My goal was to find additional localities of the prairie tiger beetle (Cicindelidia obsoleta vulturina), which inhabits dolomite glades in the area and is disjunct from the main distribution in Texas and Oklahoma. As I was checking a particularly large glade complex in Roaring River State Park, I came upon this banded garden spider (Argiope trifasciata) that had spun its web across the span of branches from a gum bumelia tree (Sideroxylon lanuginosum). As I approached the spider the web began moving back and forth quite vigorously, and it occurred to me that there was not nearly enough wind for the web to be shaking to such degree. I stood still, and eventually the shaking stopped and the web became still again. To test whether it was really the spider shaking the web intentionally, I raised my net to one side and drew it closer to the spider, and once again the web began shaking back and forth just as vigorously as before. I watched the spider closely as the web shook, and I could see that the spider was actually flexing its two front pairs of legs back and forth to cause the shaking. It was clear at this point that the spider was doing this in response to my approach, probably as a defensive reaction to a perceived threat.

I suppose I have seen this behavior before but always assumed the web was just shaking in the breeze. Not until this time, with no wind to speak of and the web shaking quite rapidly, did it become clear to me that this was actually an intentional behavior exhibited by the spider. Eisner (2005) also notes this behavior, stating that Argiope spiders often engage…

…in a bobbing action, whereby through a quick flexion of its legs it sets the web into vibration, making itself a blurred target that is hard to grasp.

The photos used to make this animated gif were not easy to get. The spider was situated in a rather high and awkward-to-reach spot, and the iPhone had difficulty focusing on the spider while it was in motion. I overcame these problems by setting myself in a stable position, holding the iPhone in place, zooming the screen slightly (about 33%) and locking focus on the spider while it was still, and then asking my field buddy (Steve Penn) to approach the spider to trigger shaking. Once it began shaking it was a matter of holding down the shutter while keeping myself and the camera still long enough for a sufficient burst of photos (eight photos were used in this gif).

REFERENCE:

Eisner, T. 2005. For the Love of Insects. Harvard University Press, Cambridge, Massachusetts, 448 pp. [Google Books].

© Ted C. MacRae 2014

Pretty, little, no-name spider

/ Ted C. MacRae / 12 Comments

I don’t like posting photographs of unidentified “bugs” (insects, spiders, etc.). There are times, however, when my best efforts are thwarted and I’m left with the choice to admit defeat or relegate the photos indefinitely to the “archives”. In this case, the subject in the photos is just cute to hide. I found this bright red spider on the blossom of a flowering dogwood (Cornus florida) this past spring while hiking the North Fork Section of the Ozark Trail near Blue Hole Hollow in Howell Co., Missouri. While I am fairly certain that it belongs to the family Linyphiidae (dwarf and sheetweb spiders), I cannot decide if it is the former or the latter. Among the dwarf spiders (subfamily Erigoninae), it resembles some members of the genus Ceraticelus, while among the sheetweb spiders (subfamily Linyphiidae) it seems a good match for the genus Florinda (as suggested by Bug Eric). Whatever its identity, it is one of the prettiest and most brightly colored little spiders I have seen. (Photographed on 4 May 2014 with a Canon MP-E 65 mm 1-5X lens.)

Edit 8/22/14, 12:20 p.m.—I now believe this to be an orb weaver (family Araneidae), albeit a very small one (only ~8 mm in length); specifically something in the genus Hypsosinga. Take a look at this photo of H. rubens, which seems to be a near perfect match for the individual in these photos.

Ceraticelus minutus?Ceraticelus minutus? Ceraticelus minutus? Ceraticelus minutus? Ceraticelus minutus?

© Ted C. MacRae 2014

Mrs. Monday Jumper

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Phidippus princeps female | Howell Co., Missouri

Phidippus princeps female | Howell Co., Missouri

In my previous post, Monday Jumper, I featured a photo of a strikingly colored jumping spider (family Salticidae) that apparently represents an adult male Phidippus princeps. Far too skittish to attempt photographing in the field, I placed him in a vial and photographed him later in the hotel room but still only got one photo that was good enough to post. Shortly after gathering him up, I came across another jumping spider that proved far more cooperative for field shots. This was no doubt due in large part to the fact that she had just captured a fat, juicy caterpillar. I find predaceous insects to be far less skittish when they are involved in the act of consuming prey. This not only makes them easier to approach and photograph, but also adds a desirable natural history element to photos that is sometimes missing in “portrait-only” photographs.

Somber coloration, large abdomen, and small carapace contrast distinctly with the male

Somber coloration, large abdomen, and small carapace contrast distinctly with the male

I say “she” because of the classic female characters exhibited—relatively large and rounded abdomen (males tend to have a smaller and more tapered abdomen), smaller carapace, somber coloration, and absence of a “boxing glove” aspect to the pedipalps. Like the male I had just collected, she was on the foliage of an oak sapling, and as I began taking photographs I noticed in the preview screen the brilliant, metallic blue chelicerae that are a hallmark of the large salticid genus Phidippus. I had also presumed the male I had just collected belonged to this same genus based on gestalt, but I could have never imagined that the two individuals actually represented male and female of the very same species. Such appears to be the case, however, as a thorough perusal of the salticid galleries at BugGuide leads me to believe that the individual featured here is the adult female of Phidippus princeps.

Check out those metallic blue chelicerae!

Check out those metallic blue chelicerae!

These photos still may not approach the technical and aesthetic perfection exhibited by master salticid portraitist Thomas Shahan, but I think they do represent an improvement over my first attempt at photographing a feeding female. The first two photos are fine, but the third suffers from the focus being a little too “deep”, which seems to be my most frequent macrophotography mistake on higher mag shots. If you have any tips on how to overcome this particular problem I am all ears!

© Ted C. MacRae 2014

Monday Jumper

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Phidippus pinceps, adult male | Howell Co., Missouri (studio shot).

Phidippus princeps, adult male | Howell Co., Missouri (studio shot).

A couple of weeks ago, shortly after my friend Rich and I began hiking a 9-mile stretch of the North Fork Section of the Ozark Trail in the far southern reaches of Missouri, we encountered this colorful jumping spider (family Salticidae) on the foliage of an oak sapling. He was not at all in the mood to be photographed—dashing persistently from one side of the leaf to the other and finally dropping to the ground as I tried to close in for some shots. So active was the little guy, that even had I managed to get him within the camera’s field of view it would have been nearly impossible to get him properly focused, much less achieve a nice composition. Hoping he would be a little easier to work with in the confines of a hotel “studio”, we coaxed him into a vial with a sprig of foliage and then got him out and placed him on a branch of dogwood flowers (Cornus florida) that evening once we were in our room. Yes—he was easier to work with, but only by the fact that being in a hotel room made it more difficult for him to escape! He was just as active as in the field, darting from flower to flower in his persistent efforts to elude the large glass eye that kept trying to look at him. For many subjects, I would have given up rather than spend an inordinate amount of time trying to get photographs that likely would not turn out to be what I wanted. But this spider was just so attractive—red and black and white with flashy blue chelicerae! I persisted in my efforts, got about two dozen shots off before he finally did escape, then promptly deleted all but five immediately after seeing them on the computer. The photo shown here is the only “keeper” that I can actually bring myself to post—the focus is a bit too deep, but not so much that it detracts greatly from what is otherwise a fairly decent composition. The more I shoot jumping spiders, the more I am amazed at the portraits that Thomas Shahan achieves with these delightful little arachnids.

After browsing through the salticid galleries at BugGuide, I am inclined to believe this is the species Phidippus princeps, with the coloration and white-stripes on the pedipalps suggesting it is an adult male. ID correction welcome.

© Ted C. MacRae 2014

An arboreal fishing spider

/ Ted C. MacRae / 4 Comments

Last week was my birthday, and as is my usual custom I took the day off in favor of the season’s first “official” bug collecting trip. Falling in late April as it does, my birthday usually coincides nicely with insect activity beginning in earnest here in Missouri, and for this year’s edition I decided to look for Cicindela scutellaris lecontei (Leconte’s Tiger Beetle) on sand prairies in the extreme northeastern corner of the state. Sadly, this year’s unusually protracted spring had resulted in a mostly still-sleeping landscape, and whatever hopes I had of seeing the earliest emerging adults were dashed as thick, gray clouds hung stubbornly in the sky and temperatures refused to edge much above 60°F. Still, a bad day of collecting is better than a good day of just about anything else, and in such situations there are still wintertime collecting methods—peeling bark, cutting wood, breaking stems, etc.—at my disposal.

The "W"-shaped markings on the abdomen with interrupted white borders distinguish this species from the otherwise similar D. scriptus (xxx fishing spider).

Dolomedes tenebrosus (dark fishing spider) | Frost Island Conservation Area, Clark Co., Missouri.

While exploring a sand prairie at Frost Island Conservation Area (Clark Co.), I found a large, dead willow in one of the draws that had apparently been killed by recent prescribed burning activities, and when I peeled back a section of the trunk bark I found this medium-sized spider (leg spread ~40 mm) sitting underneath. Based on general appearance I first thought it was some type of wolf spider, although it struck me odd that it would be under the bark of a tree rather than on the ground where wolf spiders are normally encountered. However, after consulting BugGuide and not finding it among the wolfies, I decided to widen the net and quickly stumbled onto the fishing spiders (genus Dolomedes, family Pisauridae). I’ve seen fishing spiders before—normally they are found at water’s edge and periodically demonstrate a remarkable ability to dash across the surface of the water to grab an errant insect, using the same surface tension for support that had trapped its hapless prey. As odd as it would have been to find a wolf spider high up in a tree, it seemed even more unlikely that I would find a fishing spider in such a dry, arboreal habitat. Things became clearer, however, after I settled on the species D. tenebrosus (dark fishing spider)—distinguished from other fishing spiders by the interrupted white borders behind the “W”-shaped markings on the abdomen (see BugGuide). According to Jacobs (2002) this species is frequently found far away from water, usually in wooded settings, and hibernates as an immature adult (penultimate instar) under—you guessed it—loose bark (also stones). Barnes (2003) also provides a good discussion of this spider along with diagnostic photos and references for further reading.

Dolomedes tenebrosus (dark fishing spider) | Clark Co., Missouri

The “W”-shaped markings on the abdomen with interrupted white borders distinguish this species.

Based on this information, I’m guessing this individual is a still hibernating subadult, presumably a female based on the small pedipalps (the little “legs” next to the mouth). The spider moved slowly across the exposed wood as I took these photographs, wandering onto sections of different color as she did. I like the two photos for different reasons—the first (light background) seems to better show the shape and silhouette of the spider, while the second (dark background) highlights the spider’s beautifully intricate markings.

REFERENCES:

Barnes, J. K. 2003. Dark fishing spider. University of Arkansas Arthropod Museum Notes 15 [full text].

Jacobs, S. 2002. Fishing spider, Dolomedes tenebrosus. PennState College of Agricultural Sciences Insect Fact Sheet [full text].

Copyright © Ted C. MacRae 2014

ESA Insect Macrophotography Workshop

/ Ted C. MacRae / 9 Comments

Today is the last day of the Entomological Society of America (ESA) Annual Meeting in Austin, Texas, and it has been an action packed week for me. Annual meetings such as this serve several purposes. In addition to seeing talks on a variety of subjects—in my case covering subjects ranging from insect resistance management to scientific outreach to beetle systematics—they also offer the chance to establish new connections with other entomologists that share common interests and reinforce existing ones. Of course, a major part of my interest in entomology revolves around insect macrophotography, and in recent years ESA has begun to cater to the entomological photographer contingent within the society. Last year’s meetings featured a macrophotography symposium titled, “Entomologists Beyond Borders” (for which I was one of the invited speakers), and this year featured an Insect Macrophotography Workshop led by Austin-based entomologist/photographer Ian Wright. Having done this for a few years now I figured a lot of the workshop might be review for me, but I still have much to learn and am willing to accept new ideas from any source. Besides, the workshop involved a field trip to a local habitat to try out our insect photography skills, and for a field junkie like me time in the field at an otherwise all-indoor event spanning close to a week is always welcome. The location of the meetings in Austin this year made this possible, as even in mid-November there still remain insects out and about that can be photographed if the weather cooperates (and it did).

This will be a somewhat different post than what I usually post here. Rather than featuring photos of a certain species and using them as a backdrop for a more detailed look at their taxonomy or natural history, I’m just going to post all the photos that I ended up keeping from the field trip portion of the workshop with just a comment or two about each. We went to the city’s nearby waste-water treatment facility, the grounds of which are wild and woolly enough to provide habitat for insects, and spent about an hour and a half seeing what we could find. For myself, it was a chance to photograph some insects I’ve not normally tried to photograph (i.e., dragonflies, ambush bugs) and get more practice on my blue sky technique. I did appreciate the chance to spend some time talking to Ian during while we traveled to the site and back, and I also ended up helping other participants with their camera equipment questions and technique suggestions. With that, here are the photos I took—I’ll be curious to see what readers think of this post format versus my more typical style.

Micrutalis calva

Micrutalis calva (Hemiptera: Membracidae) on silverleaf nightshade (Solanum elaeagnifolium).

Micrutalis calva

This species of treehopper is restricted to herbaceous plant hosts.

Anax junius

Anax junius (Odonata: Aeshnidae), one of the darner species of dragonfly.

Anax junius

This adult was perched on a dead twig tip and seemed to be “asleep.”

Anax junius

I clipped the perch and held it up for these “in-your-face” shots – it then awoke with a start and flew off.

Phymata sp.

Phymata sp. (Hemiptera: Reduviidae), one of the so-called “jagged ambush bugs.”

Phymata sp.

Formerly a separate family, ambush bugs are now combined with assassin bugs (family Reduviidae).

Acmaeodera flavomarginata

Acmaeodera flavomarginata (Coleoptera: Buprestidae).

Acmaeodera flavomarginata

This is one of a few species of jewel beetle in the southcentral US that are active during the fall.

Mecaphesa sp.

Mecaphesa sp. (Araneae: Thomisidae), one of the crab spiders

Mecaphesa sp.

Cryptic coloration allows the spider to lurk unseen by potential insect prey visiting the flower.

Gratiana pallidula

Gratiana pallidula (Coleoptera: Chrysomelidae) on silverleaf nightshade (Solanum eleagnifolium).

Gratiana pallidula

A type of tortoise beetle, adults “clamp” down against the leaf as a defense against predators.

Copyright © Ted C. MacRae 2013

Sunday Spider: Backlit Araneus

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Araneus sp. | Wildwood, St. Louis Co., Missouri

Araneus sp. | Wildwood, St. Louis Co., Missouri

Letting the dog out tonight, I encountered this spider—presumably in the genus Araneus—who had strung up her web in the corner of the doorway and was eerily backlit when I turned on the porch light. Without a tripod that would allow me to position the camera about 7′ above the floor and make use of a super long exposure, my only option for capturing the scene hand-held was to crank the ISO all the way up to 3200, ratchet down the shutter speed to 1/20th sec, and open up the aperture to f/5.6 (any lower and the shallow depth of field would have been unacceptable). Heavy-handed processing to reduce noise and increase sharpness yielded a serviceable photo; however, I’ve been thinking about getting a tripod lately, and the chance to produce much better versions of scenes like this only strengthen those thoughts.

Copyright © Ted C. MacRae 2013

And the results are in…

/ Ted C. MacRae / 30 Comments

I recently entered my first photo contest, a local competition sponsored by the Webster Groves Nature Study Society (of which I have been a member for ~30 years), and although the competition was limited to its few hundred members there were some serious cash prizes on offer. Being a noob at photo contests and a still relative newcomer to photography in general, I wasn’t sure what to expect. I thought my photos might be good enough to compete, but I also knew I would be going up against some long-time and very skilled nature photographers. The basic rules were a maximum of two submissions in no more than three of the following categories:

  • Botany
  • Entomology
  • Ornithology
  • Landscapes/habitats

Since I’ve only photographed two birds ever, I decided to submit entries to each of the other three categories. It was an interesting competition—the judges (each category had a panel of three consisting of a WNGSS board member, a natural history expert, and a photography expert) had a chance to see all of the photographs prior to the event (held last night) and select the top ten from each category, but the rest of the judging was done live at the event. Eventually, from each category a 1st place, 2nd place, and 3rd place photo was selected. The 12 winning photographs were then displayed in a continuous loop, and everybody attending the event was allowed to vote for one grand prize winner. The grand prize winner had to receive more than 50% of the vote, so a few runoff rounds were required to decide the final winner.

How did it go for me? I had a pretty good night, with three winning photographs:

Entomology—3rd place

Cicindela repanda (Bronze Tiger Beetle) | St. Louis Co., Missouri

Cicindela repanda (Bronze Tiger Beetle) | St. Louis Co., Missouri

Botany—2nd place

Hamammelis vernalis (Ozark witch hazel) | Iron Co., Missouri

Hamammelis vernalis (Ozark witch hazel) | Iron Co., Missouri

Entomology—1st place

Arctosa littoralis (beach wolf spider) | Lewis Co., Missouri

It was a thrill for me to learn that, out of the six photographs I submitted (and I really didn’t think my two landscape submissions were competitive to begin with), three were among the 12 final prize winners. That also made them eligible for the grand prize, but in this case I didn’t really expect the larger membership (which has a lot of birders) would really take to my closeup insect photographs. To my surprise, the first round of voting produced four finalists—two of which were my insect photos! The first runoff vote eliminated one photo—but not either of mine, and the second runoff eliminated one more photo—but again neither of mine. I had won the grand prize without yet knowing which photo would be the winner! In the end, the tiger beetle took the top prize. Personally, I was happy about that, because even though the photo took only 3rd place in the entomology competition, I thought it was the stronger of the two photos based on composition, the time and effort it took to work the beetle to finally “get the shot” (not that the wolf spider photo didn’t also take a lot of effort to get that close), and the natural history behavior that it captured (stilting and sun-facing for thermoregulation). I know blog commenting is becoming passé, but if you have any particular thoughts about these photos, good or bad, I would love to hear from you.

Overall I would have to say that, winner or not, participating in a photo competition was an extraordinary learning opportunity for me as I try to hone my craft. Listening to the comments of the judges in all of the categories, both on the natural history and the technical aspects of the photographs, gave me a lot of insight into how I might further improve my technique and take photographs that can be appreciated on both technical and artistic grounds. More importantly, the cash was nice, but the motivation to keep trying that I got out of the experience was priceless!

Copyright © Ted C. MacRae 2013