Tuesday, 17 April 2007

#15 A Gem of a Spider

Here's a beaut little spider that is often hanging around my garden well after most other web-building spiders have disappeared with the onset of cold weather.

The Jewel, Spiny or Christmas Spider

Austracantha minax, from family Araneidae, is commonly called the Spiny, Jewel or Christmas Spider. It's a rather cute and fearless little thing, hanging in its web on fences or bushes day and night.

An up close view of the Spiny Spider's 12mm egg sac

The female's body measures about 8mm diameter while the male is similar in appearance but only 3 to 4mm in size. So to appreciate the details of these little beauties, one needs to study them up close. Photography is ideal for this.

The upper-side of the abdomen has a smooth enamelled appearance in black and white patterns with six bulky spines, while the under-side is yellow and black. Although pattern design and colour can vary slightly, the distinctive shape can not be confused with any other spider, making indentification easy.

When disturbed, it will run up its web to shelter on short stout orange legs, looking quite comical.

A defensive pose, projecting its abdomen vertical

According to CSIRO, the Spiny Spider is found in Queensland, NSW and Victoria, and is at home in shrubby woodland.

I have seen this spider in areas of native bushland, but it is more common in gardens and amongst roadside weeds in my area. It can build a web of simple haphazard structure of a few supporting silk strands, or a neat orb web. Massive congregations of Spiny Spiders with overlapping webs are common amongst roadside vegetation.

Spider catches fly

The second picture illustrates the egg sac of the Spiny Spider that is attached to vegetation or structures close to the web. Web silk is thick, white and easily noticed.

The underside of the Spiny Spider

The eye configuration is two rows each of 4 eyes, though this is difficult to distinguish from the image below. Like most spiders, they are not aggressive, and will run for cover if disturbed.

Legs tucked up in an attempt to hide when disturbed

I have found this delightful little spider coated in ice crystals in mid winter in my garden, as well as hanging in full 40-plus degree summer sun, so it is a hardy creature indeed. I have not seen Willy Wagtails or other birds feeding on them, so perhaps they taste nasty. Watch them scurry up their web on short fat orange legs carrying a bright spiky body - they're like charming little cartoon characters!


Evan said...

We've always called the Bird Crap Spiders, and they are very, very common on farm land.

I have also never seen them in natural bushland but I haven't looked and probably wouldn't process it if I did see one. Probably will from now on :)


Gaye from the Hunter said...

hi Evan,

yes, it can resemble bird droppings, but the Celaenia kinbergi (Bird-dropping Spider) does even more so. This is the only one I have spotted in my yard:


Anonymous said...

OMG! I don't mean to offend anyone but I desperately need to get rid of gazillion jewel spiders in my front yard. They are literally killing a medium sized flowering tree in my front yard.There are so many of them nesting in it that if I were to cut out all the 'infected' branches and twigs there would be no tree left to speak off. This would be the second year in a row that we are unable to put any holiday lights because of them spiders! How does one get rid of them? My patience has runeth out! There is a huge spider in our backyard that every night builds its web on the path to our favorite sitting area, and every night we walk around giving it wide berth so as not to disturb its web. but the jeweled cuties have gone too far. Help!

Gaye from the Hunter said...


I can understand your impatience at an over-abundance of one species of spider in a concentrated area. I am unsure, however, how the spiders would be damaging the tree, and once you have culled the invaders, I suggest you give the tree some TLC in the way of appropriate care (that your nurseryman/woman should be able to advise on).

The kindest way to kill spiders (in my opinion) is to simply squash them. Insecticides cause a slow death. I realise this method is necessary if the spiders can not be manually reached.

Using two shoes, one either side of the spider, for a quick snap, is most effective. Sometimes it is difficult to get a shoe or similar firm object behind the spider web, but for such small spiders, it might be manageable.

However,I have seen infestations of the jewel spiders as you mention, and from memory it is just an absolute mass of silk and spiders, so this will be a difficult task. Perhaps if you get a garden rake or broom, and drag a large section of the mass of web at a time down to the ground, then squash the spiders this way. Yes, I would suggest the rake or broom method. Some will survive and take up residence elsewhere, so don't be concerned that you are wiping out the species - you won't be.

I wish you luck, and I would be very pleased if you would like to come back and share your success or otherwise, as I can imagine how these massive infestations can be a problem to remove - your experience with this could be of assistance to others who seek answers to this problem.

Thank you very much for your comment and questions.


Michelle said...

Hi, I am having the same issue with these beautiful creatures as anonymous. Except I am not really concerned about any trees or plants. I have just moved to this property which is farm land, and I cannot put anything in my backyard. My son's swingset, trampolene, bike, our BBQ, chairs or tables etc are covered in these spiders and their webs. I remove them and they are back the next day. If I hang clothes on the line, my clothes and the clothes line are covered in them by the time I come out to get them off. If I don 't drive my car for a day or two, it also ends up with them all over. they are on every bush and structure...in the thousands at least. I can try your methods of killing them (which I'm not keen on)and have removed the webs numerous times. But I would like to know how to prevent them from coming back, at least on my boy's playthings. Seems these spiders are at their most active in December and January and for this reason are sometimes called Christmas spiders - annoying as this is the best time to be enjoying the backyard. We moved out here to enjoy the great outdoors...but seems we are overtaken, please any answers would be greatly appreciated as this is driving us all crazy.

Gaye from the Hunter said...

hello Michelle,

I sympathise with you having this problem and dilemma in knowing how to effectively deal with it.

I am not a fan of professional pest control, but it might be an option. I once got a pest controller to spray for fleas when we moved into a house that obviously had had dogs. The treatment was not totally successful.

The problem, also, with pest control, is that many species are affected, not just the target species. It is a personal choice.

I had an infestation of Red Backed Spiders two summers ago, and I squashed as many as I could. I also resorted to insect spray for the hard to reach places, especially on outdoor furniture and my grandchildren's play areas.

Unfortunately, I don't have any sure-fire answers for you. I would think that if you knocked down the webs every day and killed the spiders in them, and kept this up for several days, that the spiders would get the message and colonise elsewhere, but this is only a guess.

If you look at my blog again and notice the egg sac, I would also suggest hunting for these egg sacs and destroying them, hence reducing next year's population.

I would be very pleased if you could let me know here, how you fare with this problem, as your experience will surely be beneficial to others.

I wish you luck.


Anonymous said...

Hi all,

I am Anita from perth WA. We did found a couple of the jewel spiders in our garden. They sure are beautifull!!
Because we never did see one before and my sister in law (who is an aussie) never did see one also, we were afraid that it would be poisend. So thank you for all the info that you gave us on this blog.

Regards Anita
And have a good 2009!!

Anonymous said...

hi Gaye,
I hate to contradict SGIO but his little gem is also found over here in Perth. I have always loved this spider ever since I was a kid going on long walks in the local bush and still love to see these little beauties when I go orchid hunting..

Gaye from the Hunter said...

hello Anonymous,

I apologise for the delay in posting your comment and responding, as I have been away.

Thank you for leaving your comment here regarding your experience of spider locations. These observations are most interesting to me and to other readers.

Oh, another orchid hunter, hey? An all-consuming and frustrating passion! Enjoy.


Gaye from the Hunter said...

hello Anita,

I apologise for the delay in posting your comment and responding, as I have been away.

Thank you for leaving a comment here. I am glad that the sharing of my nature observations has been of help to you in identifying and learning about creatures in your yard.