A well camouflaged flower spider (Misumena vatia) on a black-eyed susan (Rudbeckia hirta).
I’m not actually referring to sexually transmitted diseases in the title of this post, although pollinators can be vectors for diseases in flowers. I’ll save that for a future post. Today, I want to talk about crab spiders!
If you suffer from Arachnophobia, you are missing out on some of nature’s coolest predators. (Also, if you suffer from Arachnophobia, I’m sorry about the photo above…and the ones below…and future photos with spiders in them. I think that covers all the bases.) People have a natural attraction toward predators…they love the large mammalian and avian carnivores. But for some reason, they become very alarmed in the presence of our little arachnid friends. I can’t say I understand it, although I do try to be sympathetic.
Crab spiders are members of the family Thomisidae. They are featured in my post today because of their interesting methods for catching prey. Most crab spiders do not build the webs you may associate with other members their order (Araneae). They are called “sit and wait” or “ambush” predators because of their propensity toward hiding and leaping out to grab unsuspecting prey items.
Crab spider with syrphid fly prey (my thumb for scale).
Many, although not all, crab spiders like to do their sitting and waiting on flowers (well, wouldn’t you?). One species in particular (Misumena vatia) is known for its ability to gradually shift its colouration until it matches its flower post perfectly. This generally happens over the period of a couple days.
Same species, different flower. Misumena vatia on the plumeless thistle (Carduus acanthoides).
This species is much faster at changing from yellow to white than the reverse because it must build yellow pigment, but to turn white, all it has to do is excrete it. Ah, isn’t biology fascinating?
In the future, vegetarian spiders and common penguin misconceptions!
Great post, I hadn’t realised how they changed colour before. I’ve seen little crab spiders catching bumblebees in my London back garden. As a beekeeper I feel like I should save the bumbles, but also the spiders need to eat, so generally I don’t interfere with nature and wince as the bumbles get pounced on.
Thanks! They are pretty fascinating creatures…don’t feel too bad for the humble bee, though. They have some defenses of their own.
Do you know what species of crab spider you have?
Excellent Post! I just put up a blog on Misumena vatia, so I was curious to see what else was out there. I have not actually seen a goldenrod crab spider with its yellow coloration, but the areas I have found crab spiders all have an abundance of daisies.
I am wondering about the lovely specimen on the thistle. Are the red markings on the abdomen due to it hunting from the thistle. I have seen the red stripes on either side of the abdomen when the crab spiders are hunting from white daisies.
Thank you for the comment! I don’t know the answer to your question, unfortunately, but I can tell you that those red markings on the abdomen are common in the females of this species. Perhaps they are simply more visible when she has dumped her yellow pigment?
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