I went out yesterday to photograph some California Hedge Nettle (Stachys bullata) on the slope above the gardens. The purple flower spikes are looking lovely massed together. I stopped alongside one plant for a closer look at the flowers, and made a rather fascinating discovery.
When I pulled my eye away from the view-finder, on the far side of the plant, I noticed a bee dangling in a rather strange position. It was very difficult getting in front of the bee, because of some brush and other flowers I was trying not to squash under my feet. I managed to crane my neck around the plant just enough to see that a European honey bee (Apis mellifera), perhaps even one of my neighbor’s bees, was being dined upon by a spider that had it firmly in its grasp!
Every time I’d scrabble around to the other side of the plant, the spider would turn away from me, not willing to let me see (or potentially steal) her prize. Who can blame her, this is quite a catch! I struggled to get a photograph where I could see the spider clearly enough to actually identify it.
The crimson lateral streaks on the abdomen (just barely seen in the photograph below), and overall pale coloration, identify this spider as a female Misumena vatia, also known as the Goldenrod Crab Spider or Flower Crab Spider. This is a rather ubiquitous species that is holarctic in distribution, and is commonly found amidst sprays of goldenrod flowers in the fall.
Well, there’s no goldenrod (yet) blooming in my garden, but this spider seemed quite at home within the flowers of the California Hedge Nettle. This is the largest flower-spider species in North America. A predator that lurks among the flowers in your garden, preying on your garden pollinators. However, before you get too upset, it is a rather remarkable species.
Misumena vatia is a chameleon. This spider can change color to better camouflage itself against the flowers where it lurks!
The Goldenrod Crab Spider changes colors between yellow, white, and pale green. It changes color by secreting liquid yellow pigments (kynurenine and 3-hydroxykynurenine) into the outer cell layers of its body when in its yellow form. If the spider lurks on a white flower the yellow pigment is transferred to lower tissue layers beneath the glands containing white guanine so the white color becomes more visible. If the spider spends an extended period on a white based flower, it will eventually excrete the yellow pigment. Changing from yellow to white takes approximately 6 days. It doesn’t really come through in the photographs, but this spider was more pale green than white. Changing back from white to yellow though takes longer, between 10-25 days, because once excreted, the spider needs to re-synthesize the yellow pigments before it can employ them to change colors.
How amazing is that?