Goldenrod crab spider – female and hatchling

2008 September 6

So, once again, I was pushing my bike up the hill to home, looking at what was beside the road. And in the middle of a “Queen Anne’s Lace”[1] blossom, I saw something that looked odd. There was this black wasp that appeared to be trying to stand on its head. So I looked closer, and saw that part of the flower wasn’t actually a flower – it was a crab spider that had grabbed him by the face! Unfortunately, she dropped the wasp before I could get the blossom home to get a picture, but here she is:

This is actually a species of crab spider that I had posted earlier (Goldenrod Crab Spider, Misumena vatia), except the previous one was a male, which looks quite a bit different as far as body size and shape. He was also yellow. At the time, I said that they were reported to be able to slowly change colors between white and yellow. Since this female was hanging out on a white flower, and was white at the time, I figured that if we put her in a jar with some yellow flowers, maybe we’d see her gradually change to yellow. But that isn’t what happened. Instead, about two days after catching her, she laid eggs on the side of the jar, and boy, did she lose weight in a hurry:

Before laying eggs:

After laying eggs (and after eating two flies, which actually bulked her back up a bit):

She then wanted to hang out on her egg case and guard the eggs, so we kept her for about three weeks, with the occasional fly to keep her strength up. The above picture was after the three weeks, and as you can see, she never did turn yellow. So, now I wonder whether they don’t actually change color (maybe there are just two color phases, and some are born white while others are born yellow?), or maybe they lose the ability to change color when they reach adulthood (I wonder whether they have to molt to change color?).

Anyway, on September 1, I noticed that her egg case, which had originally been a tight little cluster of black dots swathed in silk, had turned into a slowly expanding cloud of black dots swathed in silk. Closer examination of the dots showed that they had legs. They had hatched! So, I fished one of the specks out and got it onto a special mount that I’d made for little guys like this [2]. The whole time I was fishing out one of her babies, the mother was rearing up and waving her front legs at me. If I’d been a small insect trying to eat her babies, I’d have been a goner.

So, here’s one of the little tykes[3]:

Like most babies, it has lovely huge eyes:

The new mount has the really nice feature that I can just flip it over to take pictures from either side, making it easy to get pictures of the underside:

So, in this climate, hatching out on September 1 only gives them about a month and a half to grow a bit before the first serious frost. I expect this means that they will overwinter as half-grown spiderlings. So, I put the jar out in the tall grass beside the house with the lid off, and hopefully they’ll all be able to get on with their lives. Maybe I’ll see some of them next spring.

[1] Also known as Wild Carrot. It’s all over the place. It’s not native to North America, and I’ve heard some claims that it is actually descended from domesticated carrots that went feral.

[2] I got the general idea for a new mount for small insects from Notes from the Undergrowth, who describes a nice technique for taking pictures of live dragonflies: take a mouse pad, cut out a hole big enough for the dragonfly to fit in, put the pad on a flatbed scanner, put your anesthetized dragonfly into the hole, close the lid, and scan it! What I’m doing is pretty similar, but on a smaller scale: take two microscope slides and a piece of rubber gasket material, and cut a circular hole out of the gasket. Then just get the small subject (such as a hatchling spider) into the hole, put a microscope slide on each side, and clamp the whole thing together with paper binder clips. Now it is a nice, closed unit, transparent on both sides, the glass is optically flat so you can photograph through it, and the little creature you want to photograph not only can’t get away, but it feels like it is safely inside a secure crevice, and is happy to sit pretty still.

[3] Awwwwww! Isn’t it cute? Who’s a little killing machine, then? Yes you are!

5 Responses
  1. Mary Peed permalink
    September 9, 2008

    Only you could make a little spider look cute… jeez.

  2. September 12, 2008

    Totally cool.

  3. September 14, 2008

    Thanks for the shout out. Love the pics and your project!

  4. ♦crystal♦ permalink
    November 9, 2008

    awwwwwww!!! that is kute!!♥

  5. ♦crystal♦ permalink
    November 9, 2008

    that is a happy kute story!!!♥•♥

Comments are closed.