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5 posts tagged spider

11th September, 2014

rhamphotheca:

Fishing Spiders (genus Dolomedes)
Spiders in the genus Dolomedes are often called dock spiders or fishing spiders. Nearly all species are semi-aquatic. Like water-striders, dock spiders are able to use the surface tension of water to speed across it. They are also capable of “diving” by climbing below the surface along vegetation - small hairs covering their body trap air bubbles that allow them to breathe.
Most species hunt aquatic or semi-aquatic insects. The spiders typically wait at the water’s edge with a couple of feet on the water’s surface, using extra-sensitive hairs on their legs to feel for vibrations carried through the surface tension like a spider web; then they dash out and ambush they prey. 
Some of the largest species of dock spider (reaching up to 3 in/7.5 cm across, toe-tip to toe-tip) are actually capable of catching small fish. They use claws at the tips of their forelegs to hook their prey and hold them while injecting them with paralyzing venom. This is the Six-spotted Fishing Spider (Dolomedes triton), found across the United States and southern Canada.photo by Mary Keim on Flickr
(via: Peterson Field Guides)

rhamphotheca:

Fishing Spiders (genus Dolomedes)

Spiders in the genus Dolomedes are often called dock spiders or fishing spiders. Nearly all species are semi-aquatic. Like water-striders, dock spiders are able to use the surface tension of water to speed across it. They are also capable of “diving” by climbing below the surface along vegetation - small hairs covering their body trap air bubbles that allow them to breathe.

Most species hunt aquatic or semi-aquatic insects. The spiders typically wait at the water’s edge with a couple of feet on the water’s surface, using extra-sensitive hairs on their legs to feel for vibrations carried through the surface tension like a spider web; then they dash out and ambush they prey.

Some of the largest species of dock spider (reaching up to 3 in/7.5 cm across, toe-tip to toe-tip) are actually capable of catching small fish. They use claws at the tips of their forelegs to hook their prey and hold them while injecting them with paralyzing venom. This is the Six-spotted Fishing Spider (Dolomedes triton), found across the United States and southern Canada.

photo by Mary Keim on Flickr

(via: Peterson Field Guides)

(via fauna)

20th July, 2014

The yellow jumping spider is native to Ecuador and belongs to
the subfamily Amycinae. It’s body is so transparent you can actually see the retinas of the primary eyes moving when it’s tracking prey. Jumping spiders are known for their excellent vision, which aid in hunting, courtship, and general navigation. 

(Source: youtube.com)

23rd November, 2012

intrinsicallylinkedlife:

Golden silk orb weavers (genus Nephila) are widespread in warmer regions throughout the world, with species in Australia, Asia, Africa (including Madagascar), and the Americas. 
Golden orb weavers are noted for their impressive webs, which can capture animals several times their size.
In 2012 a large individual was photographed killing and consuming a half-meter-long brown tree snake in Freshwater, Queensland. (first image) Species from Taiwan have been known to reach over 5 in, legspan included, in mountainous country
The second photograph is of a Golden orb weaver spider capturing and devouring a Chestnut-Breasted Mannikin. This individual was snapped in Australia. 

NO intrinsicallylinkedlife:

Golden silk orb weavers (genus Nephila) are widespread in warmer regions throughout the world, with species in Australia, Asia, Africa (including Madagascar), and the Americas. 
Golden orb weavers are noted for their impressive webs, which can capture animals several times their size.
In 2012 a large individual was photographed killing and consuming a half-meter-long brown tree snake in Freshwater, Queensland. (first image) Species from Taiwan have been known to reach over 5 in, legspan included, in mountainous country
The second photograph is of a Golden orb weaver spider capturing and devouring a Chestnut-Breasted Mannikin. This individual was snapped in Australia. 

NO

intrinsicallylinkedlife:

Golden silk orb weavers (genus Nephila) are widespread in warmer regions throughout the world, with species in Australia, Asia, Africa (including Madagascar), and the Americas. 

Golden orb weavers are noted for their impressive webs, which can capture animals several times their size.

In 2012 a large individual was photographed killing and consuming a half-meter-long brown tree snake in Freshwater, Queensland. (first image) Species from Taiwan have been known to reach over 5 in, legspan included, in mountainous country

The second photograph is of a Golden orb weaver spider capturing and devouring a Chestnut-Breasted Mannikin. This individual was snapped in Australia. 

NO

(via náttúrulega reikistjarna)

16th April, 2012

Dolomedes, aka. Fishing Spiders, are semi-aquatic arachnids that are covered in hydrophobic hairs, allowing them to use surface tension to walk and stand on water. The above video shows their hunting/ feeding habits. Some days you’re the spider, some days you’re the fish. 

27th January, 2012

cwnl:

Spiders Hunt With 3-D Vision

With their keen vision and deadly-accurate pounce, jumping spiders are the cats of the invertebrate world. For decades, scientists have puzzled over how the spiders’ miniature nervous systems manage such sophisticated perception and hunting behavior. A new study of Adanson’s jumping spider (Hasarius adansoni) fills in one key ingredient: an unusual form of depth perception.

Like all jumping spiders, the Adanson’s spider has eight eyes. The two big ones, front and center on the spider’s “face,” have the sharpest vision. They include a lens that projects an image onto the retina—the light-sensitive tissue at the back of the eye. That much is common in animal vision, but the jumping spider’s retina takes things a step further: It consists of not one but four distinct layers of light-sensitive cells. Biologists weren’t sure what all those layers were for, and research in the 1980s made them even more enigmatic. Studies showed that whenever an object is focused on the base layer, it is out of focus on the next layer up—which would seem to make the spider’s vision blurrier rather than sharper.

That led to a “long-standing mystery,” says Duane Harland, a biologist who studies spider vision at AgResearch in Lincoln, New Zealand, and who was not involved in the new study. “What’s the point of having a retina that’s out of focus?” The answer, it turns out, is that having two versions of the same scene—one crisp and one fuzzy—helps spiders gauge the distance to objects like fruit flies and other prey.

Continue..

cwnl:

Spiders Hunt With 3-D Vision

With their keen vision and deadly-accurate pounce, jumping spiders are the cats of the invertebrate world. For decades, scientists have puzzled over how the spiders’ miniature nervous systems manage such sophisticated perception and hunting behavior. A new study of Adanson’s jumping spider (Hasarius adansoni) fills in one key ingredient: an unusual form of depth perception.

Like all jumping spiders, the Adanson’s spider has eight eyes. The two big ones, front and center on the spider’s “face,” have the sharpest vision. They include a lens that projects an image onto the retina—the light-sensitive tissue at the back of the eye. That much is common in animal vision, but the jumping spider’s retina takes things a step further: It consists of not one but four distinct layers of light-sensitive cells. Biologists weren’t sure what all those layers were for, and research in the 1980s made them even more enigmatic. Studies showed that whenever an object is focused on the base layer, it is out of focus on the next layer up—which would seem to make the spider’s vision blurrier rather than sharper.

That led to a “long-standing mystery,” says Duane Harland, a biologist who studies spider vision at AgResearch in Lincoln, New Zealand, and who was not involved in the new study. “What’s the point of having a retina that’s out of focus?” The answer, it turns out, is that having two versions of the same scene—one crisp and one fuzzy—helps spiders gauge the distance to objects like fruit flies and other prey.

Continue..

(via Scinerds)