Why you shouldn't kill your friendly neighborhood spiders

JULY 12, 2019

by Bev Betkowski, University of Alberta

When that itsy-bitsy spider climbs up the spout, resist the urge to stomp it out—even if it makes your skin crawl.

The leggy bugs get an unfair reputation as being poisonous and creepy, when in fact most of them, particularly those native to North America, are harmless to humans and good for the ecosystem, said a University of Alberta expert.

"They aren't bad at all, there's just this innate fear we have of spiders," said conservation biologist Jaime Pinzon, who studies the arachnids as a U of A adjunct professor and researcher with the Canadian Forest Service. "If you don't bother them, they won't bug you."

Pinzon, who says he's been bitten "hundreds of times" with no harm done by spiders in the course of his work, notes that only a handful of the 48,000 species known worldwide—including more than 600 species of spiders in Alberta alone and about 1,500 species in Canada—are venomous to humans, most of them living in tropical climates.

And though some might fear climate change could bring potent tropical spiders to North America, there's no strong evidence to suggest it, Pinzon noted.

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Solitude breeds aggression in spiders (rather than vice versa)

Date:  July 2, 2019

Source:  PLOS

Spiders start out social but later turn aggressive after dispersing and becoming solitary, according to a study publishing July 2 in the open-access journal PLOS Biology by Raphael Jeanson of the National Centre for Scientific Research (CNRS) in France, and colleagues.

Many species display sociality only transiently during their life cycle. For example, spiderlings at their earliest developmental stage show mutual attraction and social tolerance before they disperse. This strongly contrasts with post-dispersal, solitary adult spiders that behave aggressively toward -- and sometimes even cannibalize -- other spiders. The onset of dispersal coincides with a sharp decline in social tolerance in many animals, but the causal relationship still remains poorly understood.

To address this question, Jeanson and his colleagues used a combination of behavioral, chemical and modeling approaches in spiderlings of a solitary species (Agelena labyrinthica, the labyrinth spider) to investigate the mechanisms controlling the developmental switch leading to the decline of social cohesion and the loss of tolerance.

They found that the process of maturation naturally causes an increase in mobility, which is itself sufficient to trigger dispersal without requiring any change in social behaviors. After spending an initial period of about five days in close proximity, spiderlings progressively dispersed without any change in the social context, that is, no aggressive interactions were observed before dispersal. By contrast, the social isolation that inevitably followed dispersal triggered aggressiveness by altering the way that individual spiders perceived others from the same species. For example, spiderlings that experienced social isolation were much more aggressive toward siblings than those reared socially. According to the authors, the findings provide strong evidence that aggression is a consequence, not a cause, of dispersal in spiderlings.

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Parasitoid wasps may turn spiders into zombies by hacking their internal code

APRIL 29, 2019

by Smithsonian Tropical Research Institute

Parasitoid wasps lay their eggs on a spider's back. This team proposes that by injecting the spider host with the molting hormone, ecdysone, the wasp induces the spider to make a special web for the wasp's pupa.

Setting off a startling chain of events, a parasitoid wasp can force a spider to weave a special web to suspend the wasp pupa just before it finishes killing its spider host. William Eberhard, staff scientist emeritus at the Smithsonian Tropical Research Institute and Marcelo Gonzaga at the Universidade Federal de Uberlândia in Brazil have assembled wide-ranging evidence that 'zombification' involves hacking existing web-spinning mechanisms by hijacking the spider's own molting hormone, ecdysone.

In a new paper published in the Biological Journal of the Linnean Society they combined a review of all known reports of different wasp species known to zombify different spider species around the world; the results from a molecular study in Brazil; and new observations of Costa Rican spiders to demonstrate several previously unappreciated patterns that suggest that the wasp larvae use ecdysone.

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Flying spiders sense meteorological conditions, use nanoscale fibers to float on the wind

The crab spider spins out tens of fine silk fibers for its aerial dispersal

Date:  June 14, 2018

Source:  PLOS

Summary:

Spiders take flight on the smallest of breezes by first sensing the wind, and then spinning out dozens of nanoscale fibers up to seven meters long, according to a study publishing June 14 in the open-access journal PLOS Biology by Moonsung Cho, Ingo Rechenberg, Peter Neubauer, and Christoph Fahrenson at the Technische Universität in Berlin. The study provides an unprecedentedly detailed look at the "ballooning" behavior that allows certain spiders to travel on the wind for hundreds of kilometers.

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Seven new spider species from Brazil named after seven famous fictional spider characters

Date:  January 10, 2018

Source:  Pensoft Publishers

Summary:

Several literary classics from the fantasy genre are further immortalized and linked together thanks to a Brazilian research team who named seven new spiders after them.

Several literary classics from the fantasy genre are further immortalised and linked together thanks to a Brazilian research team who named seven new spiders after them.

Spider characters from A Song of Ice and Fire, Harry Potter, The Lord of the Rings, The Silmarillion, H. P. Lovecraft's The Call of Cthulhu and the children's favourite Charlotte's Web and Little Miss Spider each gave a name to a new small cave-dwelling six-eyed spider inhabiting northern Brazil.

Discovered in iron caves across the state of Pará, northern Brazil, the new species belong to the same Neotropical genus Ochyrocera. They are described in a new research article published in the open access journal ZooKeys by Dr Antonio Brescovit, Dr Igor Cizauskas and Leandro Mota -- all affiliated with Instituto Butantan, Sao Paulo.

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Call to conserve 'crucial' rare Wales spider species

 27 October 2017

Action is needed to conserve Wales' rare spider species, including those which only live underground, a review has found.

Some of the 500 species of spiders that live in Wales are found almost nowhere else in the world, according to Natural Resources Wales (NRW).

They include cave spiders found in two places in south Wales and sand running spiders on beaches and sand dunes.

NRW said spiders were "crucial" to the environment.

The review, conducted by NRW in conjunction with the British Arachnological Society, found there were 654 different species of spider in the UK - with almost 500 found in Wales.

Of those, 18 species were critically endangered, with 84 species being endangered or vulnerable in Britain.

They include:

The sand running spider, which is a master of camouflage, found at three locations in Wales, including sand dunes at Morfa Harlech in Gwynedd

The cave dwelling spider, found at only two locations in south Wales, which spends its entire life underground

The fen raft spider, found at Pant y Sais National Nature Reserve and Crymlyn Bog, Swansea - it is one of Britain's largest spiders, with females measuring 13-22mm and males 10-16mm

Rhodri Dafydd, senior reserve manager for NRW, said of the sand running spider: "They're a fantastic looking thing. They're one of the most camouflaged spiders we've got, it looks exactly like a piece of sand so we have our work cut out looking for it.

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Discovery: Bernie Sanders spider

Date: September 26, 2017

Source: University of Vermont

A scientist at the University of Vermont and four of his undergraduate students have discovered 15 new species of "smiley-faced" spiders -- and named them after, among others, David Attenborough, Barack Obama, Michelle Obama, Leonardo DiCaprio, and Vermont Senator Bernie Sanders.

You won't find them in Washington, DC, Hollywood, or Vermont -- but on Caribbean islands and other southern spots you might now get a glimpse of Spintharus davidattenboroughi, S. barackobamai, S. michelleobamaae, and S. berniesandersi as well as S. davidbowiei and S. leonardodicaprioi.

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People Who Own Spiders And Reptiles Have A Harder Time Finding Love - via Herp Digest

Shannon Ullman, Editor, Your Tango, 7/21/17

Your pet might be why you're single.

Typically, having a pet scores you points when it comes to dating. Most guys have figured out that if they take a walk with their puppy, the girls just flock to them. And many women have found that men find their cat selfies kind of charming (right? I hope I’m right).

Apparently, there is a certain kind of pet out there that will seriously knock you down in dateable points. And if you have this pet, no one will date you.

According to a survey done by Woodstream, pets play a much larger role in dating than we may have thought. They surveyed 1,000 people about their pets, asking if they ever started dating someone or broke it off because of a pet.

Out of everyone surveyed, 70 percent were dog owners and 50 percent owned cats. The split between getting pets from shelters versus from family and friends was quite even. However, 49 percent of people said that getting a pet from a shelter was sexier

I agree! Someone with a heart big enough to save a shelter animal is pretty darn hot.

When asked which kind of pets people found to be the creepiest, 66 percent of men said spiders with 77 percent of women saying the same. The list went on to include snakes, mice, bees, ants, reptiles, chickens, goats, hamsters, and ferrets.

I had a ferret once, and guys, they are seriously WAY creepier than you would think. Anyway, it seems that spiders top the list, so, if you have this pet, no one will date you.

The survey digs into who uses their pets as a way to hit on someone too. I know you all were curious about that. It turns out that 21 percent of men admitted to this tactic while only 8 percent of women admitted to it.

And when it comes to getting a second date, it turns out that spiders really are killing your game. When looking at which pet was most likely to cost their owner a second date, spiders came in first with snakes and rats following close behind.

So, when it comes to your dating life, don’t think that pets don’t matter because they totally do! If you happen to be the owner of a spider, you might want to leave that tidbit out of your Tinder profile.

In fact, maybe you should just keep that sucker under your bed until your date has a chance to fall in love with you. Then, it will probably be a lot harder for them to hate on your creepy little friend. 

Aggressive spiders are quick at making accurate decisions, better at hunting unpredictable preys

Date:  July 28, 2017

Source:  National University of Singapore

Summary:  Spiders, like humans and many other animals, have distinct personalities. Two studies have unveiled interesting findings about the relationship between personality traits of spiders and their decision-making as well as hunting styles.

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Spiders lure bees for dinner by making flowers look flashier

10 July 2017

By Katie Langin

Ambush hunters normally rely on the element of surprise, opting to stay hidden until the moment of attack. But some spiders go for a flashier strategy. They reflect UV light, which makes the flowers they sit on appealing to bees – a bizarre strategy that has evolved multiple times in crab spiders, which ambush their prey instead of catching it in webs.

Felipe Gawryszewski at the Federal University of Goiás in Brazil and his team collected individuals from 68 species of crab spider in Australia, Europe and Malaysia. All of the species hunted insects using a sit, wait and pounce strategy, but some did so on drab substrates like bark and leaves while others hunted on flowers.

Using genetic information from all these species, the team pieced together a “family tree”, which showed that the flower-based hunting strategy evolved multiple times. What’s more, flower-dwelling crab spiders reflected more UV light than non-flower dwellers.

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This appears to be an effective hunting strategy as bees are more likely to visit flowers when UV-reflecting spiders are perched atop them.

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Strange silk: Why rappelling spiders don't spin out of control

July 7, 2017

The last time you watched a spider drop from the ceiling on a line of silk, it likely descended gracefully on its dragline instead of spiraling uncontrollably, because spider silk has an unusual ability to resist twisting forces.

In a new paper appearing this week in Applied Physics Letters, researchers from China and the U.K. showed that unlike human hair, metal wires or synthetic fibers, spider silk partially yields when twisted. This property quickly dissipates the energy that would otherwise send an excited spider spinning on the end of its silk.

"Spider silk is very different from other, more conventional materials," said Dabiao Liu of Huazhong University of Science and Technology. "We find that the dragline from the web hardly twists, so we want to know why."

A greater understanding of how spider silk resists spinning could lead to biomimetic fibers that mimic these properties for multiple potential uses such as in violin strings, helicopter rescue ladders and parachute cords. "If we understood how spider silk achieves this, then maybe we could incorporate the properties into our own synthetic ropes," said David Dunstan of Queen Mary University of London.

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Watch how spiders use sticky silk to win deadly wrestling match

15 June 2017

By Sam Wong

It’s a spider-eat-spider world. High-speed cameras have recorded the first footage showing how ground spiders hunt other spiders – sometimes bigger than themselves – by tying them up with sticky silk.

Ground spiders, members of the Gnaphosidae family, include 2000 species found all over the world. Unusually, they don’t build webs, instead chasing down their prey and fighting them head-to-head.

To learn more about their hunting technique, Jonas Wolff of Macquarie University in Sydney, Australia and his colleagues put ground spiders in a container with other spiders or crickets and filmed them from below.

Strong grip

In some cases, the ground spiders didn’t use silk at all, instead gripping the prey directly with their front legs and overwhelming it. More often, they tried this technique first but quickly switched to using silk if the prey turned out to be too large. The spiders stuck silk to the floor of the container before running around their prey quickly, sticking the thread to the prey’s legs as they went.

Ground spiders produce this silk in organs called piriform glands. Most spiders use piriform silk to attach the structural threads of their webs to surfaces. In ground spiders, the piriform glands are enlarged and modified to enable them to extrude a thick layer of glue very quickly.

The tubes that extrude the silk are usually retracted inside the body, but when the spider launches an attack, they inflate. This mechanism helps to prevent the tube from getting clogged up.

Taking on bigger prey is undoubtedly a high-risk strategy. One of the spider species Wolff’s team studied counter-attacked by biting the ground spider, and sometimes succeeded in killing the predator. “The risk is there and they can only reduce it by entangling and quickly immobilising the prey, but that doesn’t mean they can totally diminish the risk,” says Wolff.

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Fifty new species of spider discovered in far north Australia

New arachnids found in Queensland include brush-footed trap-door spider, which looks like a funnel web and can walk up glass doors

 

Calla Wahlquist

Tuesday 11 April 2017 08.16 BST Last modified on Wednesday 12 April 2017 02.27 BST 

More than 50 new species of spider, including a peacock spider with a “wonderful courtship behaviour, like dancing”, have been discovered in Queensland Australia’s Cape York region, during a 10-day trip by scientists from the Queensland Museum.

The new arachnids, which are now being formally classified, include a brush-footed trap-door spider, a large black creature that looks like a funnel web with the added power of being able to walk up glass doors; a new species of swift spider, with fuzzy black and white front legs; and several new species of ant spider.

It is the most new spiders ever discovered on a research trip by Bush Blitz, an Australian government funded ecological research body. Bush Blitz has funded 34 similar surveys and discovered almost 1,200 new species since being established four years ago, of which 201 have been spiders.

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