Wednesday, March 7, 2012

Fourlegs - a huntsman with only four legs

I have a new favourite, who I worry about every night. He is a juvenile huntsman, Holconia immanis, who has been in the wars. He has only four legs, and they are all on one side. Every leg has been dropped at the at the coxa-trochanter joint, near the body. He also seems to have lost the palp on his right side as well. I have not read of spiders dropping palps, but they are more correctly called pedipalps and are small legs, so that seems reasonable. (Click on images for a larger picture, if you really want to.)

Fourlegs, the night I first met him.

Dropping the legs has been done voluntarily by the spider. The ability for a spider to decide to drop the leg is called autotomy, which is under the spider's control. Apparently they don't do it under anaesthesia. Muscles close over the joint, the haemolymph (blood) pressure then presses on the joint membrane and seals the wound.

To drop four legs, poor Fourlegs must have been in a tight spot - either something had caught his legs, or he had trouble extracting them when moulting - so the legs are still in the shed skin. If bitten by a wasp or bee, the spider can drop the leg before the venom gets to its body. I don't know Fourlegs' story, but given it was four at once on one side, I am tending to believe it was a moulting mishap.

If Fourlegs moults again, then the legs will regrow, although they will probably be smaller and weaker. But at least he'll have them. If he's an adult, then this is it for life.

I've seen lots of spiders with seven legs, a few with six and even occasionally five. But never four. And all on the same side looks horrible.

The good news!!! Fourlegs was feeding last night. You can see the mashed black thing he is holding to his mouth, which is on the underside of his front section, his cephalothorax. He is using his left palp over on the right side and often seems to balance by bringing his left foreleg right across.

Fourlegs feeding, on the second night.

He also seems to have spun some silk around and is using it to help maintain balance. He looked very weird with his legs in a strange position, and hanging suspended, but I wonder if it was the only way he could hold his prey. I was sure he was dying, but he was there again tonight, and all is well.

Fourlegs balancing to feed.

He has been out for three nights now - so has survived this way for at least three days. Not far from the same spot. I will keep you updated if I see him again.

Just in case you want a lovely photo to finish on, I did manage to photograph a spider of the same size and species a few nights earlier, about ten metres from Fourlegs' current location. I have decided that it was him - because I want to. Don't look too closely and spoil my delusion. The rose thorn gives you an idea of his size.

Please don't make any gory or sick jokes about my spider. I am extraordinarily fond of Fourlegs and desperately want him to survive, moult and have to be renamed Eightlegs.

Thursday, March 1, 2012

Huntsmen - the gentle giants

When I was interviewing about arachnophobia for the book, it was the huntsmen which were mentioned most, causing far more fear than spiders which could actually do harm, such as the red-back. It's all about size, hairy legs and their unique ability to suddenly be on a wall where there was no spider just a second ago. Then - even worse - to be gone again. Where? (Click on spiders for larger image).

Badge huntsman, Neosparassus diana

There have been three different species of huntsmen (family Sparassidae) around the house so far this season. This adorable badge huntsman, Neosparassus diana, nearly ended up in the rubbish bin. Fortunately I noticed her just as I was going to throw the plastic bag in the bin. 

Badge huntsmen are smaller (about 16 mm body length when adult) compared to up to 22 mm or so for the larger species. They also tend to crunch up like this, and look most un-huntsmanlike. They are claled badge huntsmen because they have a 'badge' on the underside of the abdomen. This little one had been hassled enough, so I didn't put her on glass to photograph. She eventually got enough confidence to unscrunch and run under the table leg on the verandah, as in the first image. But fear not, I can show you a badge. Here's one I prepared earlier... (That's not his web. He's just near a black house spider web on the window).

Spiders on the window are not unusual - they are taking full advantage of our light bringing in dinner. This is the social huntsman, Delena cancerides. In the wild, they will often live in groups under the bark. This is unusual for spiders who tend to be solitary creatures unless they are after sex. Social huntsmen are large and common, up to 22 mm body length. Here is what we see from the loungeroom.

And here he is from outside.

But my favourite huntsman has been a young guy who lived in the house for a few weeks. He was known as Little Friend because he seemed small for a huntsman. Maybe he was a juvenile, because he was hanging around last May. I think he is a young spotted huntsman, Holoconia immanis, but I'm not certain. He would appear from flat openings we hadn't even realised were there, such as this door edge. [Update: May 2013- I finally identified him! He's a Victorian Huntsman, Isopedella victorialis. Thanks]

Mostly he stayed hidden, so we'd go days without seeing him. Then he'd appear. The photo below is on the kitchen ceiling when he decided he didn't want to be photographed - he's rearing up a bit and showing his fangs. I'm underneath him. They have no trouble hanging on when upside down. Incredible creatures!

Some visitors were a bit concerned about his strolling up and down the corridor continuously one day, so I conceded and put him outside.

He strolled across the window ...

... and was soon back inside. I was delighted. I just didn't tell anyone, and he stayed unobserved until the visitors left. He stayed around for a few more weeks, then was gone.

I've been very busy with finishing my doctoral thesis and my new job - a few days a week with the wonderful students at Castlemaine Secondary College. But I have a lot of photos and they will all end up here.

Update on the regulars:

They all disappeared, and I don't think any of the garden orb weavers (Eriophora pustulosa) made it to breeding. How sad is that?

But my golden orb weaver (Nephila edulis) did brilliantly - Welcome's egg sac hatched!!!! I ended up with a houseful of tiny orb weavers. That's a story to tell in the next blog!