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Winter Hummingbird Expedition to Costa Rica
in February 2006

AN APPRECIATION FOR SPIDERS

Like many students interested in teaching high school biology, we were required back in our undergraduate days at Newberry College to take the same advanced courses as biology majors: Bacteriology, comparative anatomy, embryology, genetics, etc., plus organic and physical chemistry and physics. Such a slate--still the norm today for biology AND secondary science education majors at many small colleges--provides solid background for undergrads bound for med school but does little to prepare K-12 educators to teach from an environmental perspective. Since teachers teach what they know--not what they DON'T know--they often end up shorting their students on ecology, animal behavior, evolution, and botany--unfortunate because high school students almost always show more interest in these topics than in the complexities of photosynthesis or intricacies of subcellular structure. Alas, the educational system--including most standardized testing--is typically set up to treat EVERY biology student as a potential doctor or dentist, when what we should be doing is giving ALL students a broader understanding of the environment and how humans fit into the big picture. It's little wonder the general public (and much of government and business) doesn't comprehend the importance of conserving natural resources and protecting habitat--much less such complicated concepts as global warming--or of how to live peacefully with Mother Nature rather than fighting her all the time.

Although our undergraduate biology courses at Newberry were worthwhile and well-taught, except for a class on cryptogamic botany ("non-flowering plants and their relatives" such as algae, fungi, mosses, and ferns) we were ill-trained at graduation to teach kids about nature and the environment. Fortunately, we'd always had an interest in nature study and had delved informally into reptiles and amphibians and small mammals, but when we got our first teaching job we almost immediately starting working on a Winthrop College masters degree that would provide a much broader background in natural history. Even after entomology and ornithology and a thesis project on the ferns of York County SC, we still felt under-trained in "field studies," so we took a giant leap of faith and moved the family off to the University of Minnesota to immerse ourselves in all the "-ologies" we could find. We took mammalogy, advanced ornithology, ecology, ethology, mycology, herpetology, and ichthyology--plus Minnesota vascular flora, evolution, plant-animal relationships, and several other natural history courses--later serving as a teaching assistant for many of them. And, as required in grad school, we designed and conducted an original long-term research investigation on behavioral ecology of Blue Jays (above left). After four years in Minnesota (i.e., four VERY cold winters), we felt much better prepared to teach biology to high school and college students, so we returned to York SC and what is now Hilton Pond Center to do just that. Our only regret from Minnesota days is that we missed taking a few courses that could have served us well. A good plant taxonomy class would have helped with our almost-daily task of identifying wildflowers, shrubs, and trees, and we'd like lichen expertise. But one class we really would have enjoyed would have been devoted to arachnology--the study of spiders.

All text & photos © Hilton Pond Center

Never having had a class about these eight-legged arthropods, we now figure the best way to learn spiders at this point in our career is simply to start reading all we can about them--that and spending time making careful observations in the field. One problem with self-directed spider studies is there are precious few field guides with illustrations to help identify spiders in the Carolinas. A volume we've been using for 25 years is Spiders and Their Kin by Levi & Levi--one of those little pocket guides originally published by Golden Press (1968). It includes family descriptions and rather nice paintings of many U.S. and Canadian spiders--along with some (too many, we believe) arachnids from other parts of the world. Although its scientific nomenclature is somewhat dated, we actually prefer this book to The Audubon Society Field Guide to Insects and Spiders by Milne & Milne (Chanticleer Press 1980), which despite its title doesn't include much spider info at all. Too bad there's so little available about an invertebrate class whose lineage goes back at least 300 million years to the Devonian Period.

The newest and most useful arachnid book we could find is Spiders of the Eastern United States: A Photographic Guide by Samford University biology profs Mike Howell & Ron Jenkins. Together they have put together an up-to-date volume (Pearson Education 2004) written in layperson's terms. The authors begin with excellent illustrations of spider anatomy and a synopsis of spider behavior and ecology--including web-weaving, venom production, and different hunting techniques. The bulk of the 360-page book, however, is devoted to descriptions of 35 eastern U.S. spider families, including truly excellent close-up photos of one or more representatives for each (166 species in all). We strongly recommend this book to anyone interested in spider identification and credit the authors with jump-starting us in our new-found effort to learn more about Piedmont arachnids.

It was fortuitous that our copy of Howell & Jenkins arrived recently, just before we almost stumbled over a large 3" spider flattened against the brick foundation of the old farmhouse at Hilton Pond Center (see two spider photos above). This particular arachnid was basically brown and had rather long, thin, hairy legs extended away from its body, but what really caught our attention was it was keeping a tight grip on a somewhat spherical white object. We immediately deduced the spider was a female, that the white thing was her egg case wrapped in silk, and that she was what folks generically call a "Wolf Spider." Hoping she'd stay put for a while, we snapped a couple of digital exposures through our 50mm macro lens (above) and then went back to the lab for the spider guide and a more powerful 180mm macro lens.

Although a cursory glance showed the spider had its requisite eight walking appendages, a ultra-close-up view (just above) made it look like she was protecting the egg case with an extra pair of front legs. We knew from previous reading that these were actually "pedipalps," long, leg-like mouthparts that are used to manipulate food and--in this case--to help hold an egg case. Likewise obvious through the macro lens was a pair of shiny black chelicerae tipped with black fangs used to inject venom into the spider's prey. (It appeared the spider was also using its chelicerae to grasp the egg case.) And the last important spider attribute visible in macro view was its assemblage of eight beady little eyes, so situated that our spider could see things above, in front of, and behind it.

As we photographed the spider on the wall, we got the impression her body shape and long, thin legs weren't quite what we would expect in a Wolf Spider, so we referred to our new field guide for advice. In spiders, the two main body parts are the more or less bulbous abdomen in the rear, and the anterior "cephalothorax"--a fusion of the thoracic region (to which the legs are attached) and the head (which bears the eyes and mouthparts). In the words of Howell & Jenkins, "Eye number and position are important in identification of spiders," so we checked out their chart that depicts the cephalothoraxes and eye configurations for 31 spider families.

We looked first at the illustration for the Lycosidae, which includes the Wolf Spiders--so-called, we suppose, because they are relatively large, free-ranging predators with fuzzy bodies. In this family, we learned, the cephalothorax has the outline of an elongated pear (right), and the eight eyes are in three distinct rows of four, two, and two, with the front row near the front edge of the head. Another large group of hunting spiders is the Pisauridae--collectively known as the Nursery Web Spiders--whose cephalothorax is still pear-shaped but more compressed in outline (below left). More important, the Nursery Web Spiders have all their eyes on the upper front surface of the head area--with the first row of four positioned in an arc, and the other two rows of two indistinctly separated and forming a trapezoid. When we compared these two configurations, it was pretty obvious our Hilton Pond arachnid was NOT a lycosid Wolf Spider after all, but a pisaurid Nursery Web Spider.

With that knowledge, we flipped to the section of Howell & Jenkins that deals with the Pisauridae and found a very interesting description: "This family contains medium to large spiders that superficially resemble the wolf spiders" whose wandering behavior they share. "Furthermore, the pisaurids are strongly maternalistic. The females carry and protect their egg sacs with the chelicerae and palps. Before the young emerge from the egg sac, the female builds a protective nursery web" around it, hence the family's common name. And, to really drive home the point about what kind of spider appears in our photos, Howell & Jenkins write: "Distinct from the wolf spiders, the adult pisaurid generally rests in a flattened position with legs extended."

Howell & Jenkins include other more detailed anatomic attributes that conclusively prove our spider was a pisaurid, but the behavioral and anatomic characteristics outlined above were sufficient to get the spider to family level. The next task was trying to determine the species. Howell & Jenkins state that the Pisauridae includes three genera and 13 species, with Dolomedes spp. (Fishing Spiders) and Pisaurina spp. (Nursery Web Spiders) being the most common. Thumbing through the book descriptions and photos, we determined the spider at hand was Dolomedes tenebrosus, the Dark Fishing Spider, and it was indeed a female.

D. tenebrosus is widely distributed in eastern North America from Canada to Florida and west to Texas and the Dakotas. The female is somewhat larger and less distinctly marked than the male, but both sexes are gray and/or brownish with dark-and-light rings around the legs and four W-shaped marks on the abdomen. As one of the Fishing Spiders, this species is typically found near water, where it captures insects--sometimes by tip-toeing rapidly across the water's surface. D. tenebrosus is known to stray from aquatic habitats into kitchens and basements, often causing unwarranted alarm among human inhabitants. This large species is capable of biting people but almost always keeps its fangs to itself--although it may bluff and strike out repeatedly when harassed.

As we photographed our Dark Fishing Spider at Hilton Pond Center, she eventually strolled from her perch on the foundation bricks and took a more secure position in the curl of a nearby Periwinkle leaf (above). We snapped a few more pictures and then left her alone, feeling that--thanks to our Fishing Spider and the new guide from Howell & Jenkins--we had finally taken a good first step in our effort to learn more about arachnids. Had we done so when teaching high school biology, we might have spawned a whole generation of students with a far greater appreciation for spiders--those ancient eight-legged arthropods that are kind enough to share the natural world with us humans.

All text & photos © Hilton Pond Center
"Blue Marble" satellite composite image courtesy NASA
Carapace drawings © Mike Howell & Ron Jenkins