AI
Sunday, September 16, 2012 1:31:36 PM
How Invasive Snakes Have Turned Guam Into a Spider-Infested Horror Show
Images via Isaac Chellman.
George Dvorsky
Sep 14, 2012 7:30 AM
Back in the 1940s, the highly invasive brown treesnake was accidently introduced to the island of Guam. In just four decades, these snakes had wiped out 10 of 12 native bird species, with the remaining two species forced to live in small areas, protected by snake traps. The result: an island with no bird chirps — and a 40-fold increase in the island's spider population.
And as a recent research expedition has revealed, the spiders have indeed taken over the island — a frightening example of what can happen when a critical predator is removed from an ecosystem.
Start counting
The research was conducted by biologists from Rice University, the University of Washington and the University of Guam, who were among the first to study how the loss of forest birds were impacting on the island's ecosystem. Without the insectivorous birds there to bother the spiders, the arachnids have largely taken over the place.
And as lead researcher Haldre Rogers observed, spiderwebs have indeed become a ubiquitous feature of the canopy; her team had to carry sticks and constantly wipe away the webs as they were making their way through the jungle.
And dealing with all the spiderwebs was in fact part of the job. By counting spiderwebs on both Guam and the nearby islands in the Marianas Island chain, the researchers were able to get a sense of what has happened on the island, compared to the other locations where the treesnake has not made an appearance.
And to do so, Rogers and her team — with tape measures and counters in hand — scoured the spider-infested island over the course of four months, counting webs. (So, you want to be an ecologist...)
Natural experiment
Even though this is a disturbing turn of events, at least Guam is proving to be a rather remarkable "natural experiment" for the researchers. Normally, you'd have to build a large exclosure, to simulate this sort of effect. But Guam is offering the scientists a unique real-world example of an ecosystem gone wrong, the result of a large-scale unintentional disruption of a natural system.
They discovered that, depending on the location, Guam contains anywhere from two to 40 times the normal number of spiders. Their research shows just how important insectivorous birds can be to an ecosystem. The researchers worry (and predict) that other locations in which insectivorous birds are on the decline could see a similar increase in spider populations. The closing words of their study ends rather ominously: "If insectivorous birds continue to decline, we will likely be living in a more spider-dominant world in the future."
In Guam, the treesnake is so problematic that the U.S. spends more than $1 million each year making sure airplanes and cargo are snake-free as they leave the American territory. And hunting them has not gotten any easier, since they are an elusive, nocturnal predator ["But the nocturnal reptile is hard to find, especially on the island itself; residents and tourists rarely see them, and even those who actively hunt the snakes often come up empty-handed, according to the release.", http://www.mnn.com/earth-matters/animals/stories/how-alien-snakes-have-helped-spiders-overrun-guam (no comments yet)].
Moving forward, the researchers will continue to study the island, paying particular attention to whether or not the spider population will continue to increase.
The study was published [ http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0043446 ] in PLOS.
Copyright 2012 io9
http://io9.com/5943177/how-invasive-snakes-have-turned-guam-into-a-spider+infested-horror-show [with comments]
===
Redbacks meet their match
Wasps are predators to the redback spider.
Photo: Kitty Hill
September 12, 2012
A native wasp, largely unstudied for more than 200 years, is being hailed as a predator to the dangerous Australian redback spider.
The Agenioideus nigricornis wasp was first described in 1775 by Danish entomologist Johan Christian Fabricius.
It can still be found across much of Australia but its role in containing redback populations only became apparent when a Western Australian family found one with a paralysed redback in their backyard.
Florian Irwin, 9, spotted the wasp dragging the spider to its nest and his father photographed the event and kept the specimens.
Andy Austin, from the University of Adelaide's Centre for Evolutionary Biology and Biodiversity, said the discovery prompted researchers to study the wasp more closely.
''It's the first record of a wasp preying on redback spiders and it contributes greatly to our understanding of how these wasps behave in Australia,'' Professor Austin said.
Research has now revealed the wasp stings and paralyses its prey and then drags it back to its nest, where it lays an egg on it.
The redback remains alive and once the egg hatches, the larval wasp feeds on the spider.
''Redbacks are one of the most dangerous species in Australia and they're mostly associated with human dwellings, which has been a problem for many years,'' Professor Austin said.
''The redback spider-hunting wasp is doing its part to keep the population of redbacks down, but it doesn't hunt all the time and is unlikely to completely eradicate the spiders,'' he said.
Copyright 2012 AAP
Read more: http://www.canberratimes.com.au/national/redbacks-meet-their-match-20120911-25qsb.html
===
The compelling beauty of the wasp spider
A wasp spider (Argiope bruennichi) starting to devour a dark bush cricket at Cosford Hall, Suffolk.
Photograph: Adam Gretton
In seconds the silk strands bound the victim like steel mesh and all we could see of the bush cricket was the lemon stripe of its underbelly
Mark Cocker
guardian.co.uk, Sunday 19 August 2012 16.00 EDT
What is it precisely about spiders that makes them so disliked as predators? Why did the late great Tony Hare, co-founder of the environmental group PlantLife, always call them – a little tongue in cheek, it has to be said – "the agents of Satan"? As Ted Hughes pointed out in his wonderful poem Thrushes, even our favourite songbird is a terrifying killer: "Nothing but bounce and stab / And a ravening second." In fact the victim in the horror scene we witnessed is itself a predator. It was a dark bush cricket, that bumbling long-legged relative of the grasshoppers, whose soft chirrup is now the soundtrack to East Anglia's late-summer evenings. Perhaps we forgive thrushes and bush crickets because they serenade us with their songs; the spider, by contrast, is such a silent killer.
This one ceased sucking the last juice of a fly it had snared, and dropped like fate itself on to the bush cricket that had tumbled into the web. The way the spider bound the victim was terrifying both for its speed and efficiency. The spinner glands at the rear of her abdomen fired out a belt of silk strands as fine as mist. Yet in seconds it bound the victim like steel mesh and all we could see of the bush cricket was the lemon stripe of its underbelly. Before she started to finely eat it, injecting salival juices that dissolve the inner tissues, the bush cricket had hung briefly upside down from one long leg like a carcass dangling on a butcher's meat hook. I found it so macabre (since I love bush crickets) that I suggested we free it, but the killer was actually a remarkable and beautiful beast. It was a wasp spider and this individual was one of only about 20 ever recorded in Suffolk (in Norfolk there have been just four). However, wasp spiders, first recorded in Britain in 1922, are spreading rapidly northwards, possibly aided by their predation of grasshoppers.
© 2012 Guardian News and Media Limited
http://www.guardian.co.uk/environment/2012/aug/19/cosford-hall-suffolk-wasp-spider [with comment]
===
Venom from the world's most poisonous spider could be the next Viagara
This highly venomous spider might help you in the bedroom.
(Photo: Wiki Commons)
A bite from the banana spider has long been known to cause painful, lasting erections. But diluted venom could offer a cure to erectile dysfunction.
By Bryan Nelson
Thu, Sep 13 2012 at 1:01 AM EST
Normally, finding a banana spider (Phoneutria nigriventer) lurking in your bedsheets would be a terrifying event. This deadly arachnid is listed as the most venomous spider in the world by the Guinness Book of World Records [ http://www.guinnessworldrecords.com/ ] . But scientists searching for cures to erectile dysfunction now believe the banana spider may have something to offer in the bedroom after all, reports National Geographic [ http://newswatch.nationalgeographic.com/2012/09/10/venom-from-the-banana-spider-could-be-the-new-viagra/ ].
Some of the debilitating effects of banana spider venom include loss of muscle control, breathing problems, paralysis and even death — but it has also been known to cause painful erections in men, which can last for hours and damage the penis permanently. That might not sound like a very enticing consolation for those suffering from erectile dysfunction, but scientists now believe that the potent neurotoxin could be developed into a drug that rivals Viagara.
Since Viagara and other similar drugs are only effective in two thirds of men, there is room on the market for an alternative. A recent report [ http://onlinelibrary.wiley.com/doi/10.1111/j.1743-6109.2010.01978.x/full ] in the Journal of Sexual Medicine found that a drug derived from banana spider venom was effective in helping elderly rodents overcome erectile dysfunction.
"The decrease in erectile function associated with age was partially restored 15 to 20 minutes after injection with PnTx2-6," wrote the study's authors [ http://www.dailymail.co.uk/health/article-2195208/Venom-worlds-deadliest-spider-cure-erectile-dysfunction-20-minutes.html ].
Since it works using a different pathway than that of Viagara, there is hope that it could close the gap and cure erectile dysfunction for good. That is, assuming it works as well on people as it does on rodents.
The Phoneutria nigriventer spider is typically found walking through South American jungles at night. They are unusual in that they don't maintain a lair or spin a web, opting instead to wander the forest floor in search of prey. By day the intimidating arachnids are known to hide out under rocks and fallen logs. They are aptly named "banana spiders" because they are often found in banana crates shipped from Brazil.
One alarming incident [ http://news.bbc.co.uk/2/hi/uk_news/england/somerset/4489033.stm ] saw a British pub chef bitten after receiving a crate of bananas from South America. The chef likely saved his own life by snapping a picture of the little culprit to later show doctors. Experts at the Bristol Zoo were then brought in to identify it and suggest an antidote.
The spiders only bite humans to defend themselves, though, as their venom is meant for small prey. And since their fangs are designed for penetrating smaller creatures, bites on humans do not always lead to envenomization.
Copyright © 2012 MNN Holdings, LLC
http://www.mnn.com/earth-matters/animals/stories/venom-from-the-worlds-most-poisonous-spider-could-be-the-next-viagara [with comments]
===
(linked in):
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=66821790 and preceding and following
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=71235876 and preceding and following
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=77651623 (and any future following)
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=79469690 and preceding and following
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=79608809 and preceding (and any future following)
Images via Isaac Chellman.
George Dvorsky
Sep 14, 2012 7:30 AM
Back in the 1940s, the highly invasive brown treesnake was accidently introduced to the island of Guam. In just four decades, these snakes had wiped out 10 of 12 native bird species, with the remaining two species forced to live in small areas, protected by snake traps. The result: an island with no bird chirps — and a 40-fold increase in the island's spider population.
And as a recent research expedition has revealed, the spiders have indeed taken over the island — a frightening example of what can happen when a critical predator is removed from an ecosystem.
Start counting
The research was conducted by biologists from Rice University, the University of Washington and the University of Guam, who were among the first to study how the loss of forest birds were impacting on the island's ecosystem. Without the insectivorous birds there to bother the spiders, the arachnids have largely taken over the place.
And as lead researcher Haldre Rogers observed, spiderwebs have indeed become a ubiquitous feature of the canopy; her team had to carry sticks and constantly wipe away the webs as they were making their way through the jungle.
And dealing with all the spiderwebs was in fact part of the job. By counting spiderwebs on both Guam and the nearby islands in the Marianas Island chain, the researchers were able to get a sense of what has happened on the island, compared to the other locations where the treesnake has not made an appearance.
And to do so, Rogers and her team — with tape measures and counters in hand — scoured the spider-infested island over the course of four months, counting webs. (So, you want to be an ecologist...)
Natural experiment
Even though this is a disturbing turn of events, at least Guam is proving to be a rather remarkable "natural experiment" for the researchers. Normally, you'd have to build a large exclosure, to simulate this sort of effect. But Guam is offering the scientists a unique real-world example of an ecosystem gone wrong, the result of a large-scale unintentional disruption of a natural system.
They discovered that, depending on the location, Guam contains anywhere from two to 40 times the normal number of spiders. Their research shows just how important insectivorous birds can be to an ecosystem. The researchers worry (and predict) that other locations in which insectivorous birds are on the decline could see a similar increase in spider populations. The closing words of their study ends rather ominously: "If insectivorous birds continue to decline, we will likely be living in a more spider-dominant world in the future."
In Guam, the treesnake is so problematic that the U.S. spends more than $1 million each year making sure airplanes and cargo are snake-free as they leave the American territory. And hunting them has not gotten any easier, since they are an elusive, nocturnal predator ["But the nocturnal reptile is hard to find, especially on the island itself; residents and tourists rarely see them, and even those who actively hunt the snakes often come up empty-handed, according to the release.", http://www.mnn.com/earth-matters/animals/stories/how-alien-snakes-have-helped-spiders-overrun-guam (no comments yet)].
Moving forward, the researchers will continue to study the island, paying particular attention to whether or not the spider population will continue to increase.
The study was published [ http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0043446 ] in PLOS.
Copyright 2012 io9
http://io9.com/5943177/how-invasive-snakes-have-turned-guam-into-a-spider+infested-horror-show [with comments]
===
Redbacks meet their match
Wasps are predators to the redback spider.
Photo: Kitty Hill
September 12, 2012
A native wasp, largely unstudied for more than 200 years, is being hailed as a predator to the dangerous Australian redback spider.
The Agenioideus nigricornis wasp was first described in 1775 by Danish entomologist Johan Christian Fabricius.
It can still be found across much of Australia but its role in containing redback populations only became apparent when a Western Australian family found one with a paralysed redback in their backyard.
Florian Irwin, 9, spotted the wasp dragging the spider to its nest and his father photographed the event and kept the specimens.
Andy Austin, from the University of Adelaide's Centre for Evolutionary Biology and Biodiversity, said the discovery prompted researchers to study the wasp more closely.
''It's the first record of a wasp preying on redback spiders and it contributes greatly to our understanding of how these wasps behave in Australia,'' Professor Austin said.
Research has now revealed the wasp stings and paralyses its prey and then drags it back to its nest, where it lays an egg on it.
The redback remains alive and once the egg hatches, the larval wasp feeds on the spider.
''Redbacks are one of the most dangerous species in Australia and they're mostly associated with human dwellings, which has been a problem for many years,'' Professor Austin said.
''The redback spider-hunting wasp is doing its part to keep the population of redbacks down, but it doesn't hunt all the time and is unlikely to completely eradicate the spiders,'' he said.
Copyright 2012 AAP
Read more: http://www.canberratimes.com.au/national/redbacks-meet-their-match-20120911-25qsb.html
===
The compelling beauty of the wasp spider
A wasp spider (Argiope bruennichi) starting to devour a dark bush cricket at Cosford Hall, Suffolk.
Photograph: Adam Gretton
In seconds the silk strands bound the victim like steel mesh and all we could see of the bush cricket was the lemon stripe of its underbelly
Mark Cocker
guardian.co.uk, Sunday 19 August 2012 16.00 EDT
What is it precisely about spiders that makes them so disliked as predators? Why did the late great Tony Hare, co-founder of the environmental group PlantLife, always call them – a little tongue in cheek, it has to be said – "the agents of Satan"? As Ted Hughes pointed out in his wonderful poem Thrushes, even our favourite songbird is a terrifying killer: "Nothing but bounce and stab / And a ravening second." In fact the victim in the horror scene we witnessed is itself a predator. It was a dark bush cricket, that bumbling long-legged relative of the grasshoppers, whose soft chirrup is now the soundtrack to East Anglia's late-summer evenings. Perhaps we forgive thrushes and bush crickets because they serenade us with their songs; the spider, by contrast, is such a silent killer.
This one ceased sucking the last juice of a fly it had snared, and dropped like fate itself on to the bush cricket that had tumbled into the web. The way the spider bound the victim was terrifying both for its speed and efficiency. The spinner glands at the rear of her abdomen fired out a belt of silk strands as fine as mist. Yet in seconds it bound the victim like steel mesh and all we could see of the bush cricket was the lemon stripe of its underbelly. Before she started to finely eat it, injecting salival juices that dissolve the inner tissues, the bush cricket had hung briefly upside down from one long leg like a carcass dangling on a butcher's meat hook. I found it so macabre (since I love bush crickets) that I suggested we free it, but the killer was actually a remarkable and beautiful beast. It was a wasp spider and this individual was one of only about 20 ever recorded in Suffolk (in Norfolk there have been just four). However, wasp spiders, first recorded in Britain in 1922, are spreading rapidly northwards, possibly aided by their predation of grasshoppers.
© 2012 Guardian News and Media Limited
http://www.guardian.co.uk/environment/2012/aug/19/cosford-hall-suffolk-wasp-spider [with comment]
===
Venom from the world's most poisonous spider could be the next Viagara
This highly venomous spider might help you in the bedroom.
(Photo: Wiki Commons)
A bite from the banana spider has long been known to cause painful, lasting erections. But diluted venom could offer a cure to erectile dysfunction.
By Bryan Nelson
Thu, Sep 13 2012 at 1:01 AM EST
Normally, finding a banana spider (Phoneutria nigriventer) lurking in your bedsheets would be a terrifying event. This deadly arachnid is listed as the most venomous spider in the world by the Guinness Book of World Records [ http://www.guinnessworldrecords.com/ ] . But scientists searching for cures to erectile dysfunction now believe the banana spider may have something to offer in the bedroom after all, reports National Geographic [ http://newswatch.nationalgeographic.com/2012/09/10/venom-from-the-banana-spider-could-be-the-new-viagra/ ].
Some of the debilitating effects of banana spider venom include loss of muscle control, breathing problems, paralysis and even death — but it has also been known to cause painful erections in men, which can last for hours and damage the penis permanently. That might not sound like a very enticing consolation for those suffering from erectile dysfunction, but scientists now believe that the potent neurotoxin could be developed into a drug that rivals Viagara.
Since Viagara and other similar drugs are only effective in two thirds of men, there is room on the market for an alternative. A recent report [ http://onlinelibrary.wiley.com/doi/10.1111/j.1743-6109.2010.01978.x/full ] in the Journal of Sexual Medicine found that a drug derived from banana spider venom was effective in helping elderly rodents overcome erectile dysfunction.
"The decrease in erectile function associated with age was partially restored 15 to 20 minutes after injection with PnTx2-6," wrote the study's authors [ http://www.dailymail.co.uk/health/article-2195208/Venom-worlds-deadliest-spider-cure-erectile-dysfunction-20-minutes.html ].
Since it works using a different pathway than that of Viagara, there is hope that it could close the gap and cure erectile dysfunction for good. That is, assuming it works as well on people as it does on rodents.
The Phoneutria nigriventer spider is typically found walking through South American jungles at night. They are unusual in that they don't maintain a lair or spin a web, opting instead to wander the forest floor in search of prey. By day the intimidating arachnids are known to hide out under rocks and fallen logs. They are aptly named "banana spiders" because they are often found in banana crates shipped from Brazil.
One alarming incident [ http://news.bbc.co.uk/2/hi/uk_news/england/somerset/4489033.stm ] saw a British pub chef bitten after receiving a crate of bananas from South America. The chef likely saved his own life by snapping a picture of the little culprit to later show doctors. Experts at the Bristol Zoo were then brought in to identify it and suggest an antidote.
The spiders only bite humans to defend themselves, though, as their venom is meant for small prey. And since their fangs are designed for penetrating smaller creatures, bites on humans do not always lead to envenomization.
Copyright © 2012 MNN Holdings, LLC
http://www.mnn.com/earth-matters/animals/stories/venom-from-the-worlds-most-poisonous-spider-could-be-the-next-viagara [with comments]
===
(linked in):
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=66821790 and preceding and following
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=71235876 and preceding and following
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=77651623 (and any future following)
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=79469690 and preceding and following
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=79608809 and preceding (and any future following)
Greensburg, KS - 5/4/07
"Eternal vigilance is the price of Liberty."
from John Philpot Curran, Speech
upon the Right of Election, 1790
F6
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