Monday, September 21, 2009

Argiope aurantia and Egg Case

On the morning of September 13, when we were heading out the door to go to Kansas City to see the last stage of the Tour of Missouri, we noticed that "Mrs. Lady" (our pet name for the Argiope aurantia that has built her web by our front door) had just blown an egg case.

Woo-hoo! As you might recall, we've been tracking our argiope's development since well before she was born. See here for a picture of the egg case she almost certainly hatched out of.

And here is a picture of her (we're pretty sure it's the same one) when she had her web temporarily in our yuccas. (Including a nice view of the, um, posteriormost end of her opisthosoma.)

Anyway, I think it's beautiful to see the cycle of life continue. And argiopes, also known as black and yellow garden spiders, are gloriously big. And they always seem to gravitate toward the tomato plants--they guard them from hopping and flying pests like graceful, tiger-striped protectresses.

For a long time I was quite arachnophobic, but argiopes were one of the first spiders I felt warmly toward; when one or two take up residence in your garden, they stay there all summer and become like strange little friends, miniature pet tigers, pouncing on entrapped grasshoppers, giving them a little sedative to take the "edge" off, then wrapping them up like a burrito to eat later on.

This is the first time, I think, that we have caught an argiope so soon after she's created an egg case.

Her skinniness was almost shocking. And as she hobbled around and around the case, weaving the web structure that will keep it safe through the entire winter, her legs looked wobbly and clumsy. As with all female creatures, giving birth can't be easy on her system, either. She looked exhausted. She looked sore. But she still had to weave the support webbing before she could haul off and rest.

While I was taking pictures of her, she did pause for a few moments on a tomato leaf. I didn't notice it until I looked at the pictures later, but she's actually resting on her pedipalps, using them in addition to her wobbly legs, to support her bod.

Then she got back to work on the scaffolding that surrounds and supports the egg case. No, she wasn't moving very fast at all.

She went around and around.

. . . At this point, a week later, she's back in her lovely orb, catching bugs, and looking fine. Getting her strength back. Getting ready for her next egg case!

I think, like all her kind, she's hoping it will be a good long time yet before the deathly frosts come.


Techuser said...

Interesting post
I'm studying A. argentata eggsacs, they look way different than yours from aurantia

Anonymous said...

I have had one of these lovely ladies in my garden for a few weeks. A couple of days ago I was horrified to find that she had left her web and was nowhere in sight. However, today, I discovered 2 large egg sacs that looked like miniature punching bags in amongst my pole bean vines. I had never seen these before and was hoping they were Miss argiope aurantia's- BINGO- YES! A little later I saw my first hawk moth this summer- it was sipping from hosta flowers.

Julianna Schroeder said...

Thanks for the comment! You know, she was probably in your garden all summer long, though you probably didn't see mini-her as she was growing. Also, juveniles look a lot different--different color pattern, slenderer, and so on.

And I know how disconcerting it is to get up one morning to find her web unoccupied--what happened to her? Usually you can find her, if she's decided to relocate; and if she's merely resting, she'll come back on her own.

We've had times, though, when she hasn't come back, ever, gone without a trace. I chalk it up to predation--garter snakes, perhaps, or a blue jay.

It's strange how ATTACHED we can become to these spiders. Have you seen my post about the end of the line for argiopes--the first hard frost?

Thanks again,

Nicole said...

Thanks for the play by play! I was discussing these spiders with someone, and I also happened to see two of these cocoons in my asparagus today. Now I know what they are, I will be sure to place the egg sacs somewhere safe when I clean up that bed this winter.

Julianna Schroeder said...

Thanks, Nicole, for commenting! It really is fascinating to watch these little animals do their thing each year. I think if you take care of them, they'll help take care of you--and entertain you in the process!