Spiders · Urban Ecology · Biodiversity

Observations of Golden Orb Weavers

It’s getting pretty cold Sydney in the moment, which means that most orb weaving spiders are coming towards the end of their season and I finally have some time to reconcile the work I’ve been doing for the last few months.

Lizzy-with-spider

Some of the Golden Orb Weaving spiders I released for my transplant experiment are still around so I thought I would share some of my (mostly unexplained) observations and questions about these spiders.

Observation 1) How do they die?

We’re really not sure what eats golden orb weavers. They are very conspicuous with their fat bodies and their big webs out in the open, so why don’t they get eaten more often? Maybe they are just not tasty or it could be that their strong 3D web structure is enough to deter most birds (for reasons obvious in the photo below from the telegraph news paper).

Birds must eat some of them because I’ve noticed many of my spiders missing with a large hole in the middle of the web. Also, while I was out releasing my spiders I got to experience a rare predation event first hand as a Kookaburra swooped down in front of me and gobbled one up. So I guess they are tasty!

I also found one very dead looking spider in her web next to a dead bee. The spider must have been a bit too slow in wrapping up her prey and got stung by the bee. Interestingly the next week I went back and the spider was sluggish but alive. She lasted a few more weeks.

Parasitism is probably also a large player. I found this spider dead in the web with a hole in her abdomen:

And I’ve seen a number of spiders parasitised during my trips out in the field, I felt really sorry for this little garden spider!

Observation 2) Reproduction

I placed some of my spiders out in the middle of national parks to see if they survived longer than the ones in the city. I didn’t see any other golden orb weavers in these locations and yet 3 weeks into the trial a male turns up on one of the females webs. There is no way he could have come in with the female so I guess he was just out there waiting and got very lucky? There must be lots of disappointed males out there.

I’ve also seen many females make egg sacks this year, which is a relief because many didn’t survive long enough to breed last year (it was a very hot summer). On many occasions the spider will die after she has created her egg sac, and those that don’t die often move webs. I’m not sure why they would do this, they only move ~5m and I would have thought it easier to go back to their original web.Â

 

Observation 3) Web building and… swapping?

Some of the spiders I released started making their webs straight away, by dropping down on a long thread and drifting to another branch. Almost all of the spiders I found had made their webs after the first week. But one spider, still tagged, showed up over 2 months after I had released her, in a web right next to her release spot. So she must have been sitting around for weeks, with no way to catch food… I wonder what she was waiting for.

I’ve also noticed a few occasions when spiders will swap webs. I’ve never witnessed conflict between two spiders because they usually stay in their own web but maybe the bigger one decides she wants the web of the smaller one sometimes. This also makes it quite hard to keep track of who is who, lucky most of my bee tags stayed on!

5 Comments

  1. Merlin Coughlan's Gravatar Merlin Coughlan
    March 2, 2018    

    I currently have 2 golden orb weaving spiders in my garden – one inside the chook house has a huge fat abdomen, the other outside between a couple of gum trees has the more usual almost hexagonal shaped abdomen – why the difference?
    An interesting side note, in the 10 years I have been observing them in the garden this is the first time I have noticed other spiders colonising the web of the one outside – scores of tiny dewdrop spiders scuttle round the web adding their own little touches.

  2. Andy Behr's Gravatar Andy Behr
    March 25, 2018    

    Good Day, Ms. Lowe,

    I don’t know if you’ll read this, but I hope you do. I live in the United Sates, and I LOVE spiders. I’ve contacted Rick Vetter about an unusual garden orb weaver hanging around my house that I’ve named Love. Unfortunately, orb weavers aren’t his specialty, but he did tell me some info (via email) regarding these spiders that he thought might shed some light on questions I have. I need more answers though.

    Basically, Love has been living in one of the doorways outside my house for over ten months now. When she first arrived, she was not a spiderling. She was immature, but she was growing quite rapidly. Over almost a year now, I’ve watched and studied her when I’ve had the opportunity. She is rather extraordinary in many ways, I feel.

    For one thing, she is still alive. It’s March 25, 2018, and I understand these spiders don’t live much past the early winter if their lucky. We’re in spring. Next, although her abdomen is half its size now compared to when she had a steady diet of prey, Love continues to try and spin webs every now and again. They are only constructed of radial strands as it seems her sticky thread for spinning spiral strands has run out, or she’s saving it (maybe). The webs she has constructed are not complete as well. They are missing spiral strands in different places. I cannot take a picture as her web is too light to show up on my camera. Finally, she seems to have been ‘watching’ her prey as she has spun her webs in locations of the door where many moths seems to congregate during the winter season. Also, she once connected her web to an abandoned cellar spider’s web to perhaps gain some sticky thread. I don’t know, but it was fascinating watching her consume part of her web to another and then sit on the web like a cellar spider would do. By the way, she hasn’t eaten in three months. When she did have a steady diet, she would adjust her web according to the food she needed. Thus, if she was hungry, she’d spin her web lower on the door and more in the light coming from the hallway of the house. The opposite held true if she caught a katydid, whereby she would build her web higher in the doorway, away from the light.

    The final things I would like to mention is that – and I know this is going to sound crazy – but she seems to react to my tapping on the glass part of the door. I won’t say more about that because you’ll probably think I’m a loon. One other thing I noticed is when she goes to sleep in the early morning, Love ‘backs’ into her web. In other words, she takes a few small steps backwards into her resting place. Is that normal? I’ve only seen her do it twice, but I’m not always there to see her go to bed. From what I understand, insects/arachnids don’t move backwards. Anyway, I believe Love has some shown some degree of intelligence as opposed to pure instinct. Am I wrong? Is she exhibiting just typical spider behavior?

    I’m sorry for the long post, but I wish someone could give me some definitive answers. I’ve heard of these types of orb weavers living in captivity until early spring (even then rarely), but they were fed and kept in a warm climate. Love is outside, and I’ve never fed her. I tried once but didn’t have the heart to kill a moth. I hope you can leave me a short reply because I’m beyond baffled by this spider.

    Best,
    Dr. Andy Behr
    California, U.S.A.

    • Lizzy's Gravatar Lizzy
      July 9, 2018    

      Hi Andy, Thanks for your wonderful observations! I’m sorry it’s taken me so long to see this message. Is Love still alive?
      It’s not unusual for orb weavers to be able to survive two seasons if they have had enough to eat and have a nice safe place to live.
      I hope you continue to watch and enjoy these wonderful creatures 🙂

  3. Rachael wilson's Gravatar Rachael wilson
    April 30, 2018    

    My Adelaide golden orb suddenly died with an orange looking protrusion from her abdomen; can anyone tell me what happened?

    • Lizzy's Gravatar Lizzy
      July 9, 2018    

      Orb weaving spiders are often parasitised by wasps! this could have been the case with your spider. did you see if the orange protrusion moved?

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