A confession--I was partially motivated to write this
article out of a sense of frustration.
For years I have referred to traditional
field guides for information about
the various kinds of wildlife I have observed.
Admittedly, these books have been invaluable, but
because of the general nature of the information
they contain I have frequently been left feeling
a bit unsatisfied.
Specifics are what I craved. Specifics about
appearance and characteristics. Specifics about
behaviors, distribution, and habitats. Specifics with
reliable anecdotes from all stages of
an organism's life. Obviously, including all of this
information in a simple field guide would not be
very practical. A single volume would quickly be
transformed into an entire encyclopedia set if it were
attempted. Still, there had to be a better way.
The desire for a better way is what ultimately became
the inspiration for this website. With dfwurbanwildlife.com
I realized I could collect information about wildlife
into a living document. One that could grow and be revised
as new and/or better information came in. Further, a website
would also allow me to include verifiable stories about unusual
or unexpected behaviors as they were observed.
Without question, though, the most important thing to me
was accuracy. I wanted to ensure that the information
collected on this website was as accurate as possible.
The last thing I wanted to do is contribute
to the mass of misinformation that can sometimes be
found on the internet. So, I vowed that each and every
article posted on my website would be researched as
thoroughly as possible.
That is when I discovered the difficulty of identifying
invertebrates.
I first encountered this problem when I began trying
to identify a species of burrowing crayfish I
discovered in a local field. It took me several
months of research to become comfortable enough with my
identification to proceed with a write up.
I never would have guessed that the science
in this area would be so unavailable.
Even now, I still retain some doubts about the
identification of this crayfish. This particular
species is very similar in form and function to many
other crayfish in the same general area.
It turns out that the key to differentiating between
these closely related species requires a magnified
inspection of a reproductive male's gonopods. Subtle
differences in these structures determine which
species an individual crayfish belongs to.
Further, while I am more than willing to defer to the
experts' opinions in matters like these, I have to say
that many of the documented shape variations seem so
minor that, to me, they could simply be attributed to
individual differences--It would be like assigning
people to different species based on the shape of
their noses. Small noses belong to this species, and
broad noses belong to this species, etc, etc...
To see what I mean, just try to differentiate between
P. gracilis, P. regalis, and P. stegmani based on the
available literature. I dare you!
More recently, I acquired a number of interesting
pictures of a garden variety orb weaver spider, and was
very excited about posting the photographs along with a
detailed article. So, like always, my first move was
to try to get a positive identification--exactly which
species of spider did I have here?
I began my search on the internet, and I quickly
narrowed down the possibilities to two genus: Neoscona
or Araneus. Both genus contained spiders of
similar size, shape, and color as the one I had found.
I felt certain that I would soon have a positive id.
I poured over every picture I could find, carefully
checking structural and coloration details trying to
make a positive id. Mislabeled internet photographs only
added to my confusion, and in the end, I realized that
trying to get satisfactory identification was
hopeless. Variations in individual appearances within
and between species were just too great and the
available information was too inadequate.
In spite of all my efforts, narrowing the my find
to a single species was not possible. Was the spider
Neoscona hentzi or Araneus cavaticus or something else
altogether? It was impossible to tell.
Finally, in desperation, I sent sample photographs to
experts hoping for some assistance. Here is a
sampling of what they had to say on the matter:
Expert A:
This is an orbweaver in the genus Neoscona, quite
possibly the Arabesque orbweaver (Neoscona arabesca),
but the literature is not very consistent on the anatomical
features that distinguish that species from similar
ones such as Neoscona domiciliorum.
Expert B:
The spider is an orbweaver in the family Araneidae.
The genus is most likely Araneus but there are other
genera that it could be including: Meta and Eustala.
Clearly the problem was outside of my ability to
resolve.
So, for now at least, a positive identification seems
unlikely. The specimen I photographed is long gone
now, leaving no way to do the required detailed
examination.
With a little luck, I will run across this species of
spider again when I am better equipped to make the
identification. Until then though, I will leave you
with these, hopefully interesting pictures of this
frustratingly, unidentified spider:
The spider was large with a legspan of at least an inch and a half.
The web was even larger--easily over 3 feet in diameter.
A closeup of a moth of some kind caught in the spider's web.
Here's our spider sporting various shades of light browns,
dark browns, and blacks.
An interesting view of the spider's underside.
This picture is very close to lifesize on a 17 inch
lcd monitor set to 1280x1024.
The spider and its web.
The spider from a slightly different angle.
The web's need of repair is clearly visible in this shot.
Accidentily disturbed, the spider flees to one corner of its web.
The spider captures and cocoons some kind of small green insect.
The cocooning is nearly complete.
The spider has completed wrapping its prey in webbing,
and may be injecting its victim with more venom.
The cocooning is complete. A meal for a later date.
Another one of the dainty green insects is
captured by the spider's web...
...and quickly suffers the same fate as the previous victim.
The insect is quickly subdued and cocooned in webbing.
The whole process of capturing, subduing, and cocooning
its prey usually took the spider less than a minute.
Back to the center of the web to await the next insect.
The air was full of thes small green bugs, and it did not
take long for another to be entangled.
On a different night, the web was missing, but the spider
could be found safely hidden out of the way in a nearby tree.
The next several pictures are of the spider building a new web.
Web building.
Web building.
Web building.
Web building.
Web building.
Web building. Quite a show to watch!
A defensive position?
A daytime picture of the large orb weaver.
Another look from a different angle.
During the day the spider was often absent from the center of the web.
At these times, the spider could ususally be found hunkered down under the
the cover of leaves in a nearby tree.
Here is a look at the attachment point of one of the
main strands supporting the larger spider web.
Another look at the same attachment point.
Another night, and the spider is back at its post in the
center of the web again.
Another victim!
This time the spider carried the cocooned bug back to the
center of its web.
Eating?
Soon another of the green insects is ensnared.
This insect is quickly dispatched and cocooned.
Two insects in a matter of minutes. A good night so far.
Back to the center of the web to await more prey!
Fluttering attracted me to this large, white moth trapped in
the spider's web. I don't believe the spider has been alerted to
the moth's presence as of yet.
Hunkered down under its leaf shelter once again.