Arachnids


Cyrtarachne inaequalis

What a cute and unusual thing to find — a natural smiley in the forest!! I couldn’t decide what it was at first as it was only about 8mm across. I was just thinking it might be a young snail when it suddenly dropped off the leaf on a silk thread. Oh, a spider!! It’s a kind of orb-weaver spider and its Japanese name means that it looks like a bird dropping. It should be called the Smiley Spider instead.

Cyrtarachne inaequalisCyrtarachne inaequalis

Arachnida: Araneidae
Cyrtarachne inaequalis
orb-weaver spider (lit. “bird dropping spider”) = oo-tori-no-fun-damashi

Location: Yokoyama Village near Munakata Common (Google map link)

Yes, this is a spider! It looks like an ant, but if you look closely you’ll see that it has eight legs and lots of eyes. The theory is that they use their disguise either to help them sneak up on ants to eat them, or to help them avoid being eaten by predators themselves.

While I was watching one male ant spider, another male dashed up and tried to take over his territory. They had a quick battle, just like a pair of stag beetles (or even stags!) and the original one managed to push the intruder down the tree. After a few centimeters of being pushed, the intruder gave up and ran away. A true miniature battle!

Web page showing the different species of ant spiders in Japan: here.

Myrmarachne elongataMyrmarachne elongataMyrmarachne elongataMyrmarachne elongataMyrmarachne elongata

Arachnida: Araneae
Myrmarachne elongata
= yagata-ari-gumo

Location: Near Genkai town office (Google map)

What a tough tick! It must have come into the house on my clothing (after hiking in the forest), and survived a ride in the washing machine. After this, it fell onto the floor and Shinobu trod on it and then tried to squish it with some tissue paper. She threw the “dead bug” into the bin… However, later that evening I saw it crawling across the floor! It was then that I realized it was a tick. They do carry diseases in Japan (e.g. lyme disease and scrub typhus), so we’re going to be careful to check ourselves after hikes from now on.

ticktickticktick

Arachnida: Acari (mites & ticks)
= madani
(I hate to admit defeat, but I’ve not been able to identify this species yet…)

Location: Munakata Common (Google map).

Just after I watched a fantailed skimmer (taiwan-uchiwa-yanma) take a butterfly skimmer (chou-tombo), I came across a big spider (nagakogane-gumo) that had managed to catch itself a fantail. It’s a tough world!

spider catches dragonflyspider catches dragonflyspider catches dragonflyspider catches dragonfly

Odonata: Gomphidae
Ictinogomphus pertinax = taiwan-uchiwa-yanma (Taiwan fantailed skimmer)

Araneidae:
Argiope bruennichii = nagakogane-gumo

Location: oo-ike (big pond)
- Map (image)
- Link to Google Map

I thought I was really taking a photo of an ant on a leaf… but after looking at the preview of the first shot to see whether it was in focus, I suddenly realized that it was in fact an ant-mimicking spider (arigumo)! Amazing mimicry. It was only around 5mm so I couldn’t see much detail with my own eyes (poor eyesight!) but looking at the photos, you can see that it is holding up its front legs to look like antennae. It seems that this kind of jumping spider might mimic ants in order to hunt them, or maybe as a protective measure to prevent themselves from being eaten by predators (birds or wasps) that typically avoid ants because of the formic acid they produce.

Myrmarachne spp.Myrmarachne spp.Myrmarachne spp.Myrmarachne spp.

Class: Arachnida
Order: Araneae
Family: Salticidae (jumping spider)
Myrmarachne spp. (Myrmarachne japonica?) = arigumo

Shinobu screamed for help this morning when she found a giant huntsman spider (actually a “huntswoman” really!) in the bedroom. It was a very big female with a leg span of about 15cm. A very impressive creature!
This species is also called the giant crab spider or housekeeping spider and they are common throughout the tropics/subtropics. They frequently live in houses (squeezing into cracks and behind furniture) and they could be said to be beneficial because they eat things like cockroaches and flies. They don’t spin webs but catch their prey by stealth and speed.
Due to its large size, it might look dangerous but this particular spider is not venomous (to humans) although the fangs (chelicerae) look like they could give a nasty bite! I was careful when I picked it up. By the way, the photo of the spider on its back does not show it dead, it just played dead when I put it on its back. Convenient for photographs!

Heteropoda venatoriaHeteropoda venatoriaHeteropoda venatoriaHeteropoda venatoria

Arachnida: Araneae: Sparassidae
Heteropoda venatoria (ashidakagumo)

Link to Wikipedia article on the huntsman spider family (Sprassidae): http://en.wikipedia.org/wiki/Huntsman_spider

It’s autumn and there are lots of big beautiful spiders all over the place. Some of their webs are truly amazing in size. Here are a couple of common species:

Nephila clavata
Tetragnathidae:
Nephila clavata (jorou gumo)

Argiope bruennichii
Araneidae:
Argiope bruennichii (nagakogane gumo)

Website: Common Spiders of Japan:
http://www.cyberoz.net/city/sekine/zukax.htm

I’ve been surprised at just how many different kinds of spiders live in our garden. Here are pictures of a few of them.

ant hunting spiders battle it outant hunting spiders battle it outant hunting spiderant hunting spider

The first four photos show an interesting little drama. These ant hunting spiders are tiny (not much bigger than ants themselves). The female caught an ant and the male seemed to want to take it from her. They had a brief tug of war, which the bigger female won of course. It was comical (but not so funny for the ant I guess!)

lying in wait under a flowerlying in wait under a flower

The spider waiting under the flower was pretty big (about 4cm across) and she had what looked like a very effective hunting method. As soon as anything landed on the flower, she was ready to grab it. I saw her fail on a bee, but I’m sure she would succeed on many other targets.

spider in its tunnel webinteresting websasagumosasagumo

I’ve not yet attempted to identify these spiders. Hoping to do so during the winter.