Biggest Spider?
Chris Peek
large a non-aquatic/terrestrial insect can get and still able to
function. When I weas a kid I always heard talk of giant "cave spiders"
in Borneo or elsewhere that were HUGE. Last year I saw a picture in the
Washington Post (in a review of the Smithsonian insect collection) of
what was purported to be the largest spider in the world and it was about
the size of a dinner plate leg to leg. What does spider like this eat?
Is it simply a matter of how much weight an exoskeleton can support that
keeps these sizes so (relatively) small. Also are there really big (if
not HUGE) "cave spiders" in existence or is this all horse feathers?
Lastly what is the worlds most dangerous/obnoxious spider for a trained
entomologist to handle?
Any replies re subject or relevant literature (not too technical if
possible) appreciated!
Neil Glick
Well, I'll tell you what I know. I don't know too much about arachnids,
but segments on most insects are not larger then one inch. This has to do
with their simple circulatory system. They don't have a closed system
like you or I, they're basicly filled with "goosh" as a professor of mine
put it once. The nutrients aren't carried by vessels or a beating heart.
It's all done by just walking around. Pretty cool eh? The nervous system
is an even bigger trip. Remember that old movie Them? Well, forget it!
:) An ant that size wouldn't be able to function because of the simple
system. As far as spiders the size of plates? Geez, I guess nothing is
impossible in nature, but don't expect to see any six foot roaches in the
near future. :)
Neil
The greatest pesticide ever invented..... The hammer
Frances Hannan (Zoology)
>what was purported to be the largest spider in the world and it was about
>the size of a dinner plate leg to leg. What does spider like this eat?
>
>Is it simply a matter of how much weight an exoskeleton can support that
>keeps these sizes so (relatively) small. Also are there really big (if
>not HUGE) "cave spiders" in existence or is this all horse feathers?
There is a fossil spider in the Geology museum here in Cambridge that is
two dinner plates across. It came from somewhere in the Andes and I hope
it is extinct!!!
--
Frances Hannan
BILMS, Zoology, Downing St, Cambridge, CB2 3EJ, UK
Phone (0223)336663, FAX (0223)461954
f...@mole.bio.cam.ac.uk
Benjamin Young
Neil Glick <hbeo...@huey.csun.edu> wrote:
[snip insect size limitations are due to their physiology]
>...but don't expect to see any six foot roaches in the near future. :)
Hm, didn't I read somewhere that the predecessor of the dragonfly (whose
supposed order I can't remember off-hand) was a dragon-fly-like insect with
a six-foot wing span? Huge things, long extinct. Very fast. I wish I could
remember the details.
So how did they do it?
-Ben
Brad Franklin
>Chris Peek <cp...@shore.intercom.net> writes:
>>what was purported to be the largest spider in the world and it was about
>>the size of a dinner plate leg to leg. What does spider like this eat?
Whatever it wants? :>
>>
>>Is it simply a matter of how much weight an exoskeleton can support that
>>keeps these sizes so (relatively) small. Also are there really big (if
>>not HUGE) "cave spiders" in existence or is this all horse feathers?
>There is a fossil spider in the Geology museum here in Cambridge that is
>two dinner plates across. It came from somewhere in the Andes and I hope
>it is extinct!!!
In the future, can we all try to use a more appealing unit of measurement
for spiders than the "dinner plate"? I would appreciate it greatly.
On a more serious note, what about giant lobsters? I have heard of 4 ft.
long ones. Wouldn't they be subject to the same circulatory & neural
constraints that the land-lubbing exoskeletals have?
-Brad fran...@math.wisc.edu
Doug Yanega
Franklin) wrote:
> On a more serious note, what about giant lobsters? I have heard of 4 ft.
> long ones. Wouldn't they be subject to the same circulatory & neural
> constraints that the land-lubbing exoskeletals have?
To some degree - which is why, of the numerous factors at work, the most
likely to represent the *absolute* upper limit is the fact that body and
limb volume increases cubically, but the power of a muscle is based on its
cross-sectional area. Simply put, if you had a terrestrial arthropod with
the dimensions of a giant crab or lobster or Eurypterid (sea scorpions,
probably the largest arthropods ever), it would be unable to move. In
essence, the muscles would have to be bigger in diameter than the limbs in
which they are encased, a topological impossibility. That is an inherent
problem in possessing an exoskeleton. Under water, the muscles don't have
to work quite as hard, so the upper limit is larger than on land. The only
way around this would be to either "invent" a different form of muscle
with greater per-unit power, or pressurize the hemolymph to a greater
degree and make use of hydraulic forces. If we ever find space-faring
aliens, I doubt they'll ever be giant arthropods...
--
Doug Yanega
Illinois Natural History Survey, Center for Biodiversity
607 E. Peabody Dr. Champaign, IL 61820 USA
"There are some enterprises in which a careful disorderliness is
the true method" - Herman Melville, Moby Dick
Doug Yanega
The actual mass of the *body* was probably not all that much greater than
some extant beetles and such - there are giant stick insects whose bodies
approach that of Meganeura. The ostensible "how" is that supposedly the
oxygen concentration of the atmosphere was much higher back in the
Carboniferous, which reduced the problems with the tracheal respiratory
physiology. Those critters were *still* puny by the standards of aquatic
arthropods, though (see my other posting).
Cheers,
Sam Davis
>Over the past few years something I occasionally wondered about is how
>large a non-aquatic/terrestrial insect can get and still able to
>function. When I weas a kid I always heard talk of giant "cave spiders"
>in Borneo or elsewhere that were HUGE. Last year I saw a picture in the
>Washington Post (in a review of the Smithsonian insect collection) of
>the size of a dinner plate leg to leg. What does spider like this eat?
Whatever it wants! he,he,he...sigh
>Is it simply a matter of how much weight an exoskeleton can support that
>keeps these sizes so (relatively) small. Also are there really big (if
>not HUGE) "cave spiders" in existence or is this all horse feathers?
It all depends on where you draw the line between "big", "really big" and
"huge". To me, the "dinner plate" spider is "@#$*&-ing huge", while I consider
an average, run of the mill tarantula "really big", and a garden spider "big",
but the largest spiders I've run into have been (what I call) garden spiders.
Excuse my lack of knowlege on this subject, but I'm not an entomologist, I'm an
Electrical Engineering senior, having never formally studied bugs/ insects/
creepy-crawlies since high school Bio 1.
Sam Davis
jda...@bnr.ca
jsd...@mail.utexas.edu
'BurkeZoology' C Wood
The Guiness Book of World Records (that non-technical enough for you?)
lists a specimen of the tarantula _Theraphosa leblondi_ (they misspelled
it of course) 10 inches (25 cm) in diameter *with legs extended* which,
of course, would not happen when the spider is alive. This very
tarantula species is one of those kept as pets. There aren't too many
people measuring wild tarantulas and there may be a slightly bigger
species somewhere, but the trouble is: 1) an exoskeleton is mechanically
less suited than an endoskeleton to supporting large structures, and 2) a
spider's blood transport protein, hemocyanin, is less efficient than our
hemoglobin in getting oxygen to the tissues. Therefore, _T.leblondi_ is
probably close to the limit. A larger, Tarzan-movie type spider would
not be able to either breathe or support its own weight. In captivity
leblondi can be maintained on crickets and baby mice but in the wild they
probably take large insects and small vertebrates of all kinds.
There is a large, tarantula-type spider, _Liphistius_ sp., in
caves in Malaysia, but much, much smaller than _T.leblondi_. But to an
arachnophobe, any sizable spider found in a dark cave would probably look
huge. With certain exceptions (such as in the large Malaysian bat caves),
the cave environment is food-poor and supports bugs markedly *smaller*
than their larger surface relatives.
On your last question: there are few dangerously venomous spiders
in the world, and most of these, such as the black widow group, are not
gratuitously aggressive toward people. The Australian "funnel web
spider" _Atrax_ (not related to Northern Hemisphere funnel web builders)
is reputed to be more aggressive than most and may be a candidate for
your question.
-----------Rod Crawford
Curator of Arachnids, Burke Museum, University of Washington
puff...@u.washington.edu
On 22 May 1995, Chris Peek <cp...@shore.intercom.net> wrote:
> Over the past few years something I occasionally wondered about is how
> large a non-aquatic/terrestrial insect can get and still able to
> function. When I weas a kid I always heard talk of giant "cave spiders"
> in Borneo or elsewhere that were HUGE. Last year I saw a picture in the
> Washington Post (in a review of the Smithsonian insect collection) of
> what was purported to be the largest spider in the world and it was about
> the size of a dinner plate leg to leg. What does spider like this eat?
> ..... Also are there really big (if
> not HUGE) "cave spiders" in existence or is this all horse feathers?
Clifford Huntington
In article <Pine.PTX.3.91j.95052...@carson.u.washington.edu>, 'BurkeZoology' C Wood <puff...@u.washington.edu> writes:
<snip>
|> On your last question: there are few dangerously venomous spiders
|> in the world, and most of these, such as the black widow group, are not
|> gratuitously aggressive toward people. The Australian "funnel web
|> spider" _Atrax_ (not related to Northern Hemisphere funnel web builders)
|> is reputed to be more aggressive than most and may be a candidate for
|> your question.
|> -----------Rod Crawford
|> Curator of Arachnids, Burke Museum, University of Washington
|> puff...@u.washington.edu
|>
Without any reference handy, I seem to recall reading that Oz is home
to the world's nastiest spiders.
There are at least a half dozen types that I know of (courtesy of a flyer
from a local fumigation company) that are poisonous. The two I most
commonly hear mentioned are RedBacks, a close relative of the Black Widow
(same size, very similar markings) which I understand are more common in
Queensland, and the Funnel Web, which looks like a Tarantula, and is more
common in New South Wales.
The RedBack has small fangs, so although it's poison is more toxic, it's
bites tend to only produce a bad 2-3 day hangover type effect, with some
dizziness tossed in on the side. This according to my wife, who speaks
from personal experience. The RedBack is also fairly passive, but due to
it's small size you can "sit" on one by accident more easily (what basically
happened to my wife).
The Funnel Web is more dangerous, because it has much larger fangs, and
is a bloody aggro varmint. They like dark damp areas (like under houses)
and will come out when it rains hard. If they are in a bad mood (you've
just been flooded out of home and you're soaking wet) they will "run"
across the lawn to bite you. Funnel Web bites are "somehwat" common, and
hospitals and emergency centres stock anti-venin. There are also emergency
transport facilities in place in case a hospital runs out and needs more
delivered.
Fatalities are rare, but considering the 'ickiness' factor of the
varmint, bites do get some publicity, so I can't say for sure just
"how" common they are. I do understand they happen more frequently
than shark attacks. ;)
Either spider is a risk to infants, small children, or the elderly.
The funnelweb is apparently more of a risk to healthy adults because
of the amount of poison it can inject.
Cliff. :)
--
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