Why we should love the imported Tegenaria gigantea:

Not only is it harmless to humans, but it eats Tegenaria agrestris, the
hobo spider, which was also imported from europe. Hobos are venomous and
people can have very unpleasant reactions (though so far none have been
fatal?), including illness and those necrotic wounds that keep getting
bigger for a couple of months before they start to heal. Hobos came
accidently to the pnw (probably to Seattle) in the 30s, and have been
steadily increasing their range (halfway across montana now, and down into
utah). T. gigantea came in the same way but later, and is also spreading,
but not any faster than T. agrestris, so it hasn't caught up. Not
coincidently, where T. gigantea is common, hobos aren't so much anymore, at
least around houses. Hobos weren't even known to be toxic to humans until
they came here, because they are never found around houses in their
homeland, so spider-human conflicts don't occur there.

And a note on spider ID: unlike birds, apparently you mostly can't ID them
from a picture. There are too many species that look almost alike, and too
many species that are highly variable within the species. So a reliable ID
needs microscopic analysis of the genitals. The most recommended book on
sci.bio.entomology.misc for identifing spiders to the family level is
Levi's _Spiders and their Kin_, one of the little golden guides. Start by
looking into their eyes: how many--6 or 8? How are they arranged? Along
with that, web design and where they perch in relationship to it are
important. Those seem to be able to narrow things down to one or three
families. _After_ you've got that far you can look at the rest of the
spider :-)

If you are bitten by a spider that you suspect may be poisonous, catch it
and either keep it alive in a jar or preserve it in alcohol (70% ethyl is
best, rubbing will do in a pinch). Have it IDed by a genuine arachnologist
who knows which way is up, not by the doctar or even an entomologist. For
the hobo and maybe others, treatment can depend on the age and sex of the
culprit. On the other hand, it's estimated that 80% of alledged 'spider
bites' are really insect bites or stings or even bumps from other causes
altogether. But humans have a tendency to blame spiders as a reflex.

Much of the above comes from from Rod Crawford's (curator of arachnids at
the Burke) various posts on sic.bio.entomology.misc. Any errors are
entirely due to my faulty memory. There is also a good web site about Hobo
spiders run by the guy who did most of the toxicology:

http://www.srv.net/~dkv/hoboindx.html


Other interesting spider books that I haven't seen mentioned yet:

_The Book of the Spider_ by Paul Hillyard. Hillyard covers the history of
arachnology as well as the more usual things. He also makes the point
that if you tend towards a phobia, it's a good idea to counteract it with
standard desensitization techniques if you can. Phobias tend to grow when
they're allowed to, and since what you're really afraid of is the fear
response more than the trigger, that response can often be set off more and
more easily with time unless you confront it. You don't have to go all the
way to arachnophilia :-)

_Spiders of the World_ by Ron and Ken Preston-Mafham. The Preston-Mafham
duo does lovely little-critter photography, almost all in the wild rather
than set up in a studio. They've also done the photos for _Bees of the
World_ and some of the other _*** of the World_ series. Well worth
checking out even if you don't have time to read the text.

Now if I can just ID my pretty little white and red spider who's sitting in
a jar with her brand new egg case!


Allyn Weaks
allyn at cornetto.chem.washington.edu aka allyn at u.washington.edu
Pacific Northwest Native Wildlife Gardening:
http://chemwww.chem.washington.edu/natives/