Tag Archives: spiders

Along Came A Spider

17 Aug

 

Hi blog.

 

Avid readers (surely there are one or two of you out there…) might remember that I promised one day I would write a post on a certain spider.  Well, that day has come.

 

I’ve written up on most of Japan’s large web spinners – jorogumo and onigumo spring to mind.  This time I’ve managed to get some reasonable shots of the other major orb weaver – Argiope amoena.

This spider seems to lack a common name in English, so I’ll use the local name koganegumo (黄金蜘蛛) here.

 

This spider belongs to the same genus as the wasp spider (A. bruennichi) and the St. Andrew’s cross spiders (A. keyserlingi and A. aetherea), to which it bears a strong resemblance.  Like its close relatives, the female spins a web with some kind of stabilimentum, or web decoration, and sits in the middle of the web, head downward, and the legs stretched out into an X shape.

Look what I just found! The legs are held out into an X shape, and you can see the web decoration.

The shape of the stabilimentum varies between individuals, but is typically a combination of one to four / and \ patterns extending from the centre of the web.  The best known is the X-shaped combination.  The exact function of the stabilimentum is unknown, although research suggests that it reflects ultraviolet light which attracts prey insects.

A clearer view of the stabilimentum.

 

The female koganegumo grows to just under 20 mm in body length, and has a wide abdomen.  The abdomen is decorated with wide horizontal gold and brown bands.  The male grows to a mere one fifth that size and is typically a dull brown.

It is found throughout Japan minus Hokkaido, and its range also includes the Korean peninsula, Taiwan, and parts of China.  Apparently, however, it is quite rare here in Saitama and is listed as an endangered species on a prefectural level!

 

This spider has a number of regional names, some of which are shared with the jorogumo.  (Actually, a lot of people are actually unaware of the differences between the two – they tend to lump spiders into a single category, usually a visceral conglomerate of fear and disgust)

 

Like their close relatives, these spiders have a single year life span, with males mating once or twice – they never survive a second mating – and eggs are laid in summer.  The hatchling spiders survive over winter, but the adults die during autumn.

Larger than life. Actually, she’s quite a pretty spider, don’t you think?

 

While not embedded deeply in folklore like the jorogumo, the koganegumo used to play a part in children’s games – its web was used to catch cicadas.

Furthermore, there is a tradition of pitting female spiders against each other in the old Satsuma fief in modern Kagoshima.

Apparently, this was started in 1592 by Yoshihiro Shimazu, lord of Kagoshima, as a means of instilling fighting spirit among his men.  The event continues to be held today and is designated an important cultural event.

 

The spiders are deprived of food for three days before the fight.  They are placed on a horizontal stick and forced to encounter.  The winner is the spider which forces its opponent to fall, starts to wrap it in silk, or succeeds in biting its foe.

It seems that intervention prevents arachnidian deaths.

As seen on NHK news…

 

I’m sure you’ll agree that the koganegumo is a fascinating and beautiful spider.

Spiders on the Storm

24 Oct

The signs of impending winter are upon us.  While the heat made one final appearance for the Sports Day long weekend, nights and early mornings have become decidedly chilly.  The sun is setting early, and leaves are changing colour.

 

Recent news has been dominated with the landslides on Izu Oshima island, caused by Typhoon 26, which have resulted in over two-dozen confirmed deaths and nearly a dozen still missing.  To make matters worse, Typhoon 27 is following a similar path, and Typhoon 28 is also on the way.

 

It was on one of those warmer, sunny mornings (autumn is known as the season of clear skies, except when the typhoons come through and dump several hundred millimetres of rain in a few hours) when I noticed how big some of the jorogumo had become, and was spotting their webs in all kinds of places.  I saw around half a dozen in the 20+ mm  class along the Azuma River, their webs stretched between the cherry branches and the guard rail.  Further along I spotted a few more, smaller spiders with webs spanned between electricity poles and roadside hedges.

 

That was when I spotted a web with stabilimentum (web decoration), a linear zigzag pattern.  This web no doubt belonged to a member of the genus Argiope.  This was going to be worth examining more closely.

Aha! An orb-weaver. The web decoration is a dead giveaway.

 

Unfortunately, the spider had positioned herself on the other side of her web, facing the morning traffic.  Traffic is not only a genuine life-threatening risk, it is also the curse of arachnidian photography – every vehicle that passes caused the web to sway several centimetres, and out of focus.  The low, direct sun also played havoc with exposure, and I had to abandon my attempts, wondering if the spider would still be there after the typhoon…

 

…which it was.

 

Thanks to my field guide, I was able to quickly identify the spider as a wasp spider (Argiope bruennichi).  This spider has a wide range, and is found right across the Japanese archapeligo, much of the Asian mainland, parts of Africa to northern and central Europe.  Unfortunately, I have not been able to find the etymology of its English name.  The Japanese name, nagakoganegumo (長黄金蜘蛛), is somewhat easier to deal with; it suggests that it looks like the orb-web spider (Argiope amoena) or koganegumo, but is longer.

 

My best photo attempt – not easy with just a mobile phone. The shape of the body and stripes made identification easy.

Female wasp spiders can grow to 25 mm in length, and this one was about that size.  Males are typically about half the size of females, and their markings are not as distinct as the females’.  Like other orb-weaver species, males often do not survive mating.

 

While many other Argiope species spin X-shaped or diagonal stablimenta, wasp spiders tend to spin rings as juveniles and vertical linear patterns as adults.

The adult spider typically waits in the centre of its web, head downwards.

 

Closer up… notice that she is missing a leg?

The wasp spider is less agressive than A. amoena, and so are not used in spider-fighting bouts (I hope to get some good photos of  amoena next year and write a little about spider fighting).  Its venom is not known to be harmful to humans (usual caveats apply), and in some agricultural circles the spider is favoured as a predator of pests.  For example, in parts of Kochi it is known as ineushiwaka, or “Ushiwaka of the rice” (a reference to Ushiwakamaru, the childhood alias of warlord-cum-folk hero Minamoto no Yoshitsune)

 

These spiders have a single-year life cycle, and time for the adults to die is rapidly approaching as I write this.  Their eggs will already have been laid in their egg sacs – about 900 per sac – and will hatch next spring.  By August, the next generation of mature adults will be with us.

There was a redback on the … vending machine?

24 Jan

Just when you thought it was safe to buy a can of coffee…

From the Mainichi:

http://mainichi.jp/english/english/newsselect/news/20130123p2a00m0na008000c.html

Man hospitalized after being bitten by redback spider hiding in vending machine

A redback spider (photo courtesy of the Fukuoka Municipal Government)
A redback spider (photo courtesy of the Fukuoka Municipal Government)

FUKUOKA — A man in his 30s was taken to hospital on Jan. 21 after being bitten by what is believed to be a redback spider while picking up a canned coffee from a vending machine at a park here, the Fukuoka Municipal Government announced on Jan. 22.

The man is suffering from headaches and nausea, but the spider bite is not life-threatening, the municipal government said. The incident prompted the local government to urge people not to touch redback spiders or other suspicious spiders with their bare hands. The man was bitten by the spider at Maizuru Park in Fukuoka’s Chuo Ward.

In September 2012, an 86-year-old woman from Fukuoka’s Higashi Ward was taken to hospital after being bitten by a redback spider.

According to the public health department at the Fukuoka Municipal Government, at about 12:30 p.m. on Jan. 21, the man bought a canned coffee from a vending machine near a parking lot in Maizuru Park. When he pulled his hand from a slot of the vending machine, the spider crawled up through his right sleeve and bit his forearm, it said. About two hours later he called for an ambulance because he started to feel acute pain and nausea.

In collaboration with the company that installed the vending machine, the Fukuoka Municipal Government looked around for spiders in the area on Jan. 21 and 22, but they could not find any of the creatures.

A spokesperson for the company that installed the vending machine said, “We check to make sure that bugs and the like do not enter the machine when we bring in products. Because they are food products, we cannot use insecticides. Therefore, we can’t take any further measures.”

The redback spider is endemic to Australia, and there has been a sharp rise in the number of cases of people being bitten by redback spiders in Japan since around 2006. The cumulative number of reported cases of redback bites until last year stood at about 65 in Osaka Prefecture and one each in Aichi and Fukuoka prefectures.

January 23, 2013(Mainichi Japan)

Eight Legged Freaks

26 Sep

I am homeward-bound along route 50, the road connecting Tokorozawa with Sayama.  I pass the motley collection of garages and long-closed restaurants to the field.  And just a couple of dozen centimetres from my face, I cruise past one of the largest spiders I’ve ever seen.

 

Imagine this just 30 cm from your face!

 

This one had constructed a web from the electrical and fibre-optic cables to the ground, a neat classical web.  Some kind of orb-weaver, but with a large, triangular abdomen and no colour markings.

Note the horn-like knobs on the abdomen.

“Onigumo?” I ask myself as I struggle to get what photos I can with my mobile phone in the fading light – my cause not helped by the trucks going past, blowing the web and its owner out of my focus point.

 

No, that is NOT a spider climbling the power cables… but it was almost big enough!

 

Back home, I dive into my recently-acquired A Field Guide to the Plants and Animals of Saitama and confirm that, yes, it is onigumo.  The problem is, which one?  You see, onigumo (鬼蜘蛛) in Japanese refers not only to a species (Araneus ventricosus), but also to the whole Araneus genus of spiders – that’s some 650 species!!  Furthermore, I am unable to find a common English name.  (Ghost spider has been suggested, but this term refers to several different species)

 

The word “oni” in Japanese means “demon” or “ogre”, but can be a reference to size – the largest dragonflies (Anotogaster sieboldii) are known as oniyanma (usually 鬼蜻蜓, but sometimes馬大頭), and the tiger lily is called oniyuri (鬼百合).  That said, the bumps on the spider’s triangular-shaped abdomen are reminiscent of a demon’s horns…

 

A web search indicates that Araneus ventricosus is the most likely candidate.  The literature indicates that females may reach 30mm across the body, and my spider would be pretty close to that mark.

They are night-active orb weavers, famous for disassembling their webs every morning and for the speed at which they spin new webs.  I must have encountered this one soon after she (yes, anything that big in the arachnidian world is female – males reach just over half of that) completed her web for the evening.  She was ready to catch moths, crickets and unwary cyclists.

 

Spider awaiting the arrival of a cyclist, er, meal?

 

 

Meanwhile, other spiders had been in the news for other reasons…

 

From the Mainichi:

http://mainichi.jp/english/english/newsselect/news/20120904p2a00m0na005000c.html

Woman bitten by redback spider at Fukuoka rest home

          A redback spider is pictured in this photograph provided by the Fukuoka Municipal Government.
A redback spider is pictured in this photograph provided by the Fukuoka Municipal Government.

FUKUOKA — An elderly woman who was bitten on the leg by a redback spider at a welfare facility here was treated with expired antivenin, municipal government officials have announced.

Officials said the 86-year-old woman was bitten in the morning on Sept. 3, and was taken to a hospital in the city’s Nishi Ward. At one point she was suffering breathing problems, but her condition started improving after she was given the serum.

About 30 redback spiders were subsequently found in the area around the welfare facility, and staff exterminated them.

The antivenin was purchased by the Fukuoka Children’s Hospital and Medical Center for Infectious Diseases in Fukuoka’s Chuo Ward in October 2010. It expired on Aug. 10 this year. Staff noticed that the hospital’s stock had expired on Aug. 23 and ordered more, but supplies had not arrived by the time the woman was bitten. A doctor at the facility administered the expired serum after judging that it would have some effect.

“We’re sorry for our lax administration of the serum,” a representative of the city’s Public Health and Welfare Bureau commented.

It is expected to take some time for new serum stock to arrive, and the medical center is asking other prefectures to help out with supplies in the meantime.

Redback spider bites can cause pain, perspiration and nausea, and can leave children and elderly people in serious condition. About 10 people are bitten by the spiders in Japan each year, but the latest case was the first reported in Fukuoka Prefecture.

September 04, 2012(Mainichi Japan)

Click here for the original Japanese story

And the Daily Yomiuri:

http://www.yomiuri.co.jp/dy/national/T120906004839.htm

 

Over 100 poisonous spiders found

The Yomiuri Shimbun

AMAGASAKI, Hyogo–Authorities on Thursday exterminated more than 100 poisonous redback spiders spotted near the Inagawa river the day before, police said.

According to the police, a local man spotted a swarm of spiders at about 7:30 p.m. Wednesday in Amagasaki, Hyogo Prefecture and reported it to police.

Police officers rushed to the scene and found more than 100 spiders inside a drainage pipe in a river wall about five meters high located along a walkway.

Officials of a local health center later confirmed the spiders to be redbacks, a species legally designated as invasive and foreign. They were exterminated by health center officials Thursday morning.

(Sep. 7, 2012)

 

 

The TV news reported that some 30 council workers and police were deployed to kill the spiders.  I don’t know why they didn’t just recruit a couple of Aussies with a can of Mortein each…

The things you see when you don’t have a camera

21 Jul

Just a brief collection of assorted pics hastily taken with my mobile phone.  These are ones that actually turned out – my attempts to photograph herons, kingfishers, lizards and tree frogs with  my mobile inevitably end up as tiny blurs – assuming I even have time to get the thing out of my pocket and switch to camera mode.

How I wish I could afford to carry a real camera around with me all the time, as there are encounters that happen anywhere.

Like this snake…

A snake just outside my school entrance. It slithered into the bushes before I could get a decent shot or identify it.

And this…

A spider of the genus Argiope. Note the stabilimentum (web decoration). This was taken at an amusement park.

Or this…

An unidentified insect – I guess it’s a bush cricket (katydid). This one was about 3 cm long.

A little closer…

And this…

A snail by the roadside. The shell was about 3 cm across.

A closer look. At least this one didn’t get away!

Saving those yen…

Her Ladyship

19 Nov

Great horns she had, and behind her short stalk-like neck was her huge swollen body, a vast bloated bag, swaying and sagging between her legs; its great bulk was black, blotched with livid marks, but the belly underneath was pale and luminous and gave forth a stench.  Her legs were bent, with great knobbed joints high above her back, and hairs that stuck out like steel spines, and at each leg’s end there was a claw.

 The Lord of the Rings

 

It is said that humans instinctively find certain features attractive – large eyes, for example – and this is why babies (both human and animal) appeal to us.

In the same vein, a dislike of sudden scuttling movement, multiple appendages and the like is also thought to be inherent.  Humans have an a priori fear of spiders.

 

Now, I am NOT particularly scared of spiders.  Growing up in suburban and semi-rural South Australia brought me into frequent contact with black house spiders, white-tailed spiders and redbacks.  I once brought a red-headed mouse spider home for identification; and for many years, one of my designated household jobs was the removal of huntsman spiders – some with a leg span of around 20cm – from the kitchen and neighbour’s house.  Even today, I am quite happy to let one of the small wolf spiders that enter my house crawl onto my hand so I can take it back outside.

 

But there is one spider that does manage to give me the willies.  Jorogumo.

What the spider looks like moments before you walk into its web..

A member of the golden orb-web family, Nephila clavata is beautifully coloured.  The females are large for web spinners – body lengths of 25mm are not uncommon.  They also have very long legs and spin large webs, up to a metre across.  The whole trampoline effect intensifies their already rapid-but-jerky movement.  As I said, humans are predispositioned to dislike this.

I also mentioned their bright colouring – yellow and black striped legs with a blue-ish tinge near the body and a yellow and black abdomen, often with a red band.  In nature, bright colours, particularly red, are usually a warning sign – “Mess with me and you’ll regret it”.

However, these are not aggressive spiders, and their venom is not known to be dangerous to humans.

A spider viewed from the back.

I should point out here that practically every spider is venomous. There are just a number of factors determining whether or not the bite is dangerous – the ability of the fangs to penetrate human skin, the type of venom, the volume injected, individual allergic reactions, and the presence of bacteria on the spider’s fangs.

 

The jorogumo (女郎蜘蛛) is sometimes confused with spiders of the genus Argiope (the genus that includes the St. Andrew’s cross spider), particularly Argiope amoena, known locally as koganegumo (黄金蜘蛛).  I hope to write about these spiders in a later post.

 

There are two popular theories as to the origins of the jorogumo’s name.  The more common one is 女郎, basically a prostitute; the other is 上臈, a high-ranked court lady.  The former name is also sometimes shared with a mythical creature in folklore (also written 絡新婦 – “ensnaring bride”) that possesses some arachnidian traits.

 

“Jorogumo” by Toriyama Sekien. A public domain image.

Old stories tell of men meeting a beautiful woman and falling for her charms (sometimes marrying them, sometimes being led to their house)  When the man falls asleep, the woman transforms into a giant spider, binds him in her web, and devours him.  Eventually a young samurai sees through the deception and kills the spider.

A variation has the woman carrying a child (possibly representing the spider’s egg-sac).  The woman asks the samurai to hold the child.  The samurai sees through the disguise and makes to slash at the woman and child.  The child screams, and the samurai escapes.  He returns the next morning to find a giant spider crushed under a huge rock, and countless human skulls under the house.  Had he carried the child, he would have been pinned down when it transformed into the rock and been easy prey for the jorogumo.

 

Typical of many spiders, mating is a dangerous affair for the male – he often ends up getting eaten as part of the bargain.  His chances of survival are best if the female has just eaten or has just molted.

 

A female in the 20mm+ class, with remains of her last meal still wrapped up. Many thanks to workmate Mat for this shot.

As I write this, the spiders are approaching the final stage of their life cycle.  Eggs are laid in late autumn and early winter and hatch in the spring.

A big thank-you to workmate Mat, who took time out to help me find and photograph specimens for this post.

%d bloggers like this: