Wednesday, October 14, 2009

Woodlouse Hunter (Dysdera crocata)

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I was quite shocked to find this gal crawling around my basement floor. First, it was very large, slightly bigger than a quarter, and second because I could see it's fangs from 6 feet up!

Dysdera crocata is a hunting spider found from New England to Georgia and west to California. It is also a commonly encountered spider in England, northern Europe, and Australia. The Woodlouse Hunter preys on pill bugs or sow bugs (order Isopoda), sometimes beetles, and derives its common name from the British common name for these crustaceans. D. crocata is known to feed on other arthropods as well. This is the only species of the family Dysderidae known to occur in North America.

Unlike 99% of spiders, they have only six eyes, grouped closely together. Their jaws are relatively large, with long fangs for piercing through the hard armor of their prey. These are definitely the longest fangs on any spider I've found in Minnesota. The body of the woodlouse hunter is generally smooth, not hairy. The cephalothorax (front segment) is reddish orange to maroon, and the abdomen is usually tan or grayish white. Males are smaller in size, and their genitalia are visible on the ends of the pedipalps. This is a female.

These spiders hunt at night, actively searching out their prey. Woodlouse hunters do not build webs, but construct small, silken oval-shaped retreats. They overwinter as adults, and after mating in the spring, females deposit about 70 eggs in their retreat. When the young hatch, they stay near the mother for a short period of time.

Raynox DCR-250 mounted on my Panasonic Lumix FZ8.

Saturday, September 5, 2009

Jumping Spider (Sitticus fasciger)

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I was out looking for a few spiders to photograph today, and boy was it slim pickings! I found several of this species, Sitticus fasciger, but they were all females which I already have studio pictures of. Finally I found this guy, a nice sized male.

Males of the species have smaller, more slender abdomens, and larger dark palps, as you can see here. Here's a picture of a female. For an informative paper on behavior and identification of this species, look here.

Sitticus fasciger is originally from Asia, specifically the Russia/China area. They are almost always found in conjunction with man. Their favorite habitats are man made structures like stone walls, houses, building walls and such, which is exactly where I found this guy. They were apparently introduced into the US in the 50's.

Raynox DCR-150 and Raynox DCR-250, stacked, and mounted on my Panasonic Lumix FZ8.

Friday, September 4, 2009

Jumping Spider (Tutelina elegans)

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Tutelina is a small genus of very interesting American salticids that deserve much more study. These spiders, which themselves seem to be generalized ant mimics, readily attack and feed upon small ants. It is generally unusual for ant mimics to attack ants, as more often the spiders are Batesian ant mimics. The fewer ants they eat, the more there are to hide amongst.

This is a female. The males have a very interesting double mohawk style hairdo that is quite something to behold. The females are a pretty emerald green, and I really like her flashy yellow striped legs.

Raynox DCR-150 and Raynox DCR-250, stacked and mounted on my Panasonic Lumix FZ8.

Friday, August 28, 2009

Grass Spider (Agelenopsis sp.)

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For this genus of spiders, the web is a horizontal, sheet-like web, with a small funnel-like tube off to a side and a 3-dimensional barrier web over the top. When a flying insect hits the barrier, it falls into the sheet below. The funnel (or tube) is what the family (Agelenidae) is named for, and is used by the spider for hunting. The spider will lie in wait in the funnel, and when an insect flies hits the barrier and falls on the web, the spider will rush out, very quickly check to see if it is prey, and if it is prey, bite it. The venom is fast-acting on the prey, so once the prey is subdued the spider will drag the prey back into the funnel (for safety while eating, and to prevent other insects from recognizing the danger that lurks below on the web).

For Agelenopsis spp. spiders, the web is not sticky. If the insect lands/falls on the web, the web will actually become tangled around the prey's feet, temporarily ensnaring it in the web. The funnel web for Agelenopsis is a distinctive web, and often is noticed in bushes and grass, especially in the early fall mornings, where the dew has collected on the web. The webs can be expansive, covering several square feet, or just small webs in the grass.

Raynox DCR-250 mounted on my Panasonic Lumix FZ8.

Saturday, August 8, 2009

Common Barn Spider (Araneus cavaticus)

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The Common Barn Spider (Araneus cavaticus) is a nocturnal, black and brown spider with striped legs. They also have markings on their underside that are typically a black background with two white marks inside the black, although color ranges can be quite magnificent. The photo above shows the classic pose these spiders exhibit, with the front four legs grouped together, and the back legs tucked similarly. They will sit quite still for pictures in this pose, but trust me, if you bump the table they will pop up and run like lightning!

Like many other species of orb weavers, it takes down its web and rebuilds another web every evening. Its "orb" web is the archetypical web that contains symmetrical spokes connected by a spiral inside. They hide during the day and at night will sit in the middle of the web and wait for an insect to land on the web when hunting.

These spiders are aggressive toward each other (and toward humans). They will attack each other if in close quarters, though many may inhabit the same structure or area at any given time. They are most commonly found in rafters and wooden structures in suburban and rural structures or areas, and on boats near lakes, thus getting their name, "barn spider".

They are mostly found in North America in late summer and through autumn. Barn spiders are most common in the Northeast US and Canada.

When agitated (by a puff of air, for instance) these spiders sometimes bounce up and down in the center of their webs, possibly in an attempt to look larger and more threatening.

Raynox DCR-150 and Raynox DCR-250, stacked and mounted on my Panasonic Lumix FZ8.

Friday, August 7, 2009

Male Common House Spider (Parasteatoda tepidariorum)

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A Male Common House Spider (Parasteatoda tepidariorum). You can see the difference between this and the female of the species in the post below. Notice especially the much smaller abdomen and much larger black palps on the front.

They are generally dull in appearance, with patterns consisting of brown shades for coloration, often giving a vague spotted appearance that is particularly noticeable on the legs. Their average body size is a quarter-inch long, but they can be an inch or more across with legs outspread. These traits combined allow the spiders to blend into the background and escape notice.

Like some other species of the family Theridiidae, P. tepidariorum shares a body shape and size that makes it similar to widow spiders, which have venom that is classified as potentially dangerous.

These spiders are not aggressive. They are not known to bite people frequently, nor is their venom known to be dangerous to human beings. When removed from their webs their poor vision and body type renders them nearly helpless. Their only concern seems to be to find and return to their own web or build another one. They do not wander around inside houses except to find a secure place to build a web. Since these spiders are harmless and their diet consists of pests such as flies and mosquitos, as well as other small invertebrates found in houses, tolerating their presence in human homes is beneficial.

Raynox DCR-150 and Raynox DCR-250, stacked and mounted on my Panasonic Lumix FZ8.

Thursday, August 6, 2009

Female Common House Spider (Parasteatoda tepidariorum)

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A Female Common House Spider (Parasteatoda tepidariorum). A male of the species is posted above. Notice how large and bulbous the female abdomen is. Also notice the small palps.

They are generally dull in appearance, with patterns consisting of brown shades for coloration, often giving a vague spotted appearance that is particularly noticeable on the legs. Their average body size is a quarter-inch long, but they can be an inch or more across with legs outspread. These traits combined allow the spiders to blend into the background and escape notice.

Like some other species of the family Theridiidae, P. tepidariorum shares a body shape and size that makes it similar to widow spiders, which have venom that is classified as potentially dangerous.

These spiders are not aggressive. They are not known to bite people frequently, nor is their venom known to be dangerous to human beings. When removed from their webs their poor vision and bulbous abdomen renders them nearly helpless. Their only concern seems to be to find and return to their own web or build another one. They do not wander around inside houses except to find a secure place to build a web. Since these spiders are harmless and their diet consists of pests such as flies and mosquitos, as well as other small invertebrates found in houses, tolerating their presence in human homes is beneficial.

Raynox DCR-150 and Raynox DCR-250, stacked and mounted on my Panasonic Lumix FZ8.

Friday, July 31, 2009

Marbled Cobweb Spider (Enoplognatha marmorata)

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Marbled Cobweb Spider (Enoplognatha marmorata)

This spider occurs almost exclusivley in association with man. It can be found in the corners of houses, garages and sheds where it feeds on anything that stumbles into its web (often woodlice). It's web is a tangle of criss-cross threads that is typical of theridiids. The intensity of the colouring is variable between individuals but the patterning is fairly consisitant.

Raynox DCR-150 and Raynox DCR-250 stacked and mounted on my Panasonic Lumix FZ8.

Long Legged Sac Spider (Cheiracanthium sp.)

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I found this guy on my bedroom ceiling. A lot less menacing than it looks, probably only 3/8 of an inch including legs.

Several reports classify these spiders as possibly harmful, but real study shows their bites are not poisonous or necrotic to humans.

Raynox DCR-150 and Raynox DCR-250 stacked and mounted on my Panasonic Lumix FZ8. I used a simple paper plate as a flash diffuser for the lighting. Worked out very well if you ask me.

Longjawed Orbweaver (Tetragnatha sp.)

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A Longjawed Orbweaver (Tetragnatha sp.) I found inside my tackle box. Brought it inside for a few photos.

Tetragnatha is a genus of spiders containing hundreds of species. They are found all over the world, although most occur in the tropics and subtropics. They are commonly called "stretch spiders", referring to their elongated body form. When disturbed they will stretch their front legs forward and the others in the other direction, thus being able to hide on blades of grass or similar elongated substrates. They are also able to run over water.

Raynox DCR-250 mounted on my Panasonic Lumix FZ8.

Bold Jumping Spider (Phidippus audax)

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Phidippus audax is a common jumping spider of North America. It is commonly referred to as the Bold Jumping Spider. The average size of adults ranges from roughly 1/2 to 3/4 inches in body length, though I have found several in Texas around the 1" mark.

These spiders are typically black with a pattern of spots and stripes on their abdomen and legs. Often these spots are orange, yellow or red tinted in juveniles, turning white as the spider matures.

The Bold Jumping Spider belongs to the genus Phidippus, a group of jumping spiders easily identified both by their relatively large size and their iridescent chelicerae. In the case of P. audax, these chelicerae are a bright, metallic green or blue.

These spiders have been known to jump up to 50 times their own body length, and the male may jump away during mating if the female approaches too quickly.

Like other jumping spiders, due to their large, forward facing eyes, they have very good stereoscopic vision. This aides them when stalking prey, and allows some visual communication with others of their species, such as courting 'dances'.

While this guy may look very menacing, he's really only about 3/8 inch long. A curious little bugger too.

Raynox DCR-150 and Raynox DCR-250, stacked, and mounted on my Panasonic Lumix FZ8.

Leaf Curling Sac Spider (Clubiona sp.)

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Not much is known about these guys. Actually this is a female. I could only narrow it down to a genus level because my favorite identification site is woefully lacking in this family, and no other site on the intarwebs knows anything about them.

I found this spider in very long grass. It had curled one of the grass blades over and made a home for itself. Given that this genus is called the Leaf Curling Sac Spiders, I thought the name and behavior fit quite well. There are at least 3 species that look almost exactly like this one, so I guess it'd take an expert to identify it to species level. You can't see it from this angle, but it has a furry grey mottled abdomen.

Even without much information I was impressed by the very large black chelicerae and extra large fangs. Really a great spider to shoot in my little studio. As always it was released unharmed.

Raynox DCR-150 and Raynox DCR-250 stacked and mounted on my Panasonic Lumix FZ8.

Female Jumping Spider (Sitticus fasciger)

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I was snooping around outside of the house today looking for something to shoot in my little studio, and I found three of these gals. This is a female Sitticus fasciger, the males have smaller, more slender abdomens, and larger, very much less furry, black palps. For an informative paper on behavior and identification of this species, look here.

Sitticus fasciger is originally from Asia, specifically the Russia/China area. They are almost always found in conjunction with man. Their favorite habitats are manmade structures like stone walls, houses, building walls and such, which is exactly where I found this girl. They were apparently introduced into the US in the 50's.

Raynox DCR-150 and Raynox DCR-250 stacked and mounted on my Panasonic Lumix FZ8.