Sometimes you can't see the trees for the forest.
And sometimes you can't see the spider at all in a purple forest.
Such was the case this week when a tiny white crab spider cunningly figured out the best place to prey was in a flowering artichoke.
At first the spider crawled on top of the thistle, as honey bees dived in and out, threading through the petals, foraging for nectar and pollen. Did the bees spot the predator? If they did, they paid no attention. They were acting like kids jumping into a pool on a triple-digit temperature day on the first day of summer.
Then the spider slipped over to the edge of the purple forest and hid in the shadows. There it reigned supreme, Purple Reign. Unseen, and out of the heat.
Crab Spider: 3
Honey Bees: 0
Three sisters became breakfast, lunch and dinner.
Hunger in a purple forest.
Let's hear it for biocontrol.
You've seen lady beetles, aka ladybugs, preying on aphids.
But have you seen an assassin bug attack a spotted cucumber beetle?
How about a crab spider munching on a stink bug?
All biocontrol, part of integrated pest management (IPM).
If you access the University of California Statewide Integrated Pest Management Program (UC IPM) website or more specifically, this page, you'll learn that "Integrated pest management, or IPM, is a process you can use to solve pest problems while minimizing risks to people and the environment. IPM can be used to manage all kinds of pests anywhere–in urban, agricultural, and wildland or natural areas."
Or, UC IPM's more in-depth definition:
"IPM is an ecosystem-based strategy that focuses on long-term prevention of pests or their damage through a combination of techniques such as biological control, habitat manipulation, modification of cultural practices, and use of resistant varieties. Pesticides are used only after monitoring indicates they are needed according to established guidelines, and treatments are made with the goal of removing only the target organism. Pest control materials are selected and applied in a manner that minimizes risks to human health, beneficial and nontarget organisms, and the environment."
Think of biocontrol as beneficial: "Biological control is the beneficial action of predators, parasites, pathogens, and competitors in controlling pests and their damage. Biological control provided by these living organisms (collectively called "natural enemies") is especially important for reducing the numbers of pest insects and mites, but biological control agents can also contribute to the control of weed, pathogen, nematode or vertebrate pests."--UC IPM
Yesterday we witnessed an incredible case of biocontrol in action.
At Bodega Bay's Doran Regional Park, Sonoma County, we spotted a great blue heron stepping stealthily through a thatch of ice plant in the Jetty campground. It was 6:30 in the morning. As campers slept in their recreational vehicles a few feet away, the great blue heron just kept stepping silently through the ice plant. One step. Another step. And another.
And then it happened. Its long sharp beak speared a rodent. Yes, they eat rodents. It crunched the body from head to toe, breaking the bones, and then swallowed it whole.
Not a pretty picture, but a simple case of biocontrol, compliments of a hungry heron.
It was a good day for a crab spider.
It was NOT a good day for a honey bee.
It's early evening and here's this bee foraging on a bluebeard plant, Caryopteris x clandonensis, totally unaware of the ambush predator lying in wait.
The hunter and the hunted.
A venomous bite and it's all over.
These spiders, often called the "white death spider," are camouflage artists. They can turn colors, from yellow to white, or white to yellow. You'll often see yellow crab spiders on golden rod Solidago or a predominantly yellow plant, like blanketflower, Gallardia.
"These spiders change color by secreting a liquid yellow pigment into the outer cell layer of the body," according to Wikipedia. "On a white base, this pigment is transported into lower layers, so that inner glands, filled with white guanine, become visible. The color similarity between the spider and the flower is well matched with a white flower, in particular the Chaerophyllum temulum, compared to a yellow flower based on the spectral reflectance functions."
"If the spider dwells longer on a white plant, the yellow pigment is often excreted," Wikipedia says. "It will then take the spider much longer to change to yellow, because it will have to produce the yellow pigment first. The color change is induced by visual feedback; spiders with painted eyes were found to have lost this ability. The color change from white to yellow takes between 10 and 25 days, the reverse about six days. The yellow pigments have been identified as kynurenine and 3-hydroxykynurenine."
One thing's for sure: everybody eats in the pollinator garden.
What's for dinner?
A crab spider, camouflaged in our lavender patch, didn't catch a honey bee, a butterfly, an ant or a syrphid fly.
No, it nailed a green bottle fly.
We couldn't help but notice. The fly's metallic blue-green coloring stood in sharp contrast to the white spider.
One venomous bite to kill it. And soon the fly, Lucilia sericata, was toast. Milk toast.
Crab spiders don't build webs to trap their prey. They're cunning and agile hunters that spring into action when an unsuspecting prey appears on the scene. They belong to the family Thomisidae, which includes some 175 genera and more than 2100 species. And they're ancient: spiders date back 400 million years ago.
Do you like spiders? You should.
“Spiders are an incredibly diverse group with more than 50,000 species described with probably another 200,000 remaining to yet be discovered,” says spider expert Jason Bond, the Evert and Marion Schlinger Endowed Chair in Insect Systematics in the UC Davis Department of Entomology and Nematology.
It's worth repeating what Professor Bond said about spiders at the Bohart Museum of Entomology open house, “Eight-Legged Wonders,” on Saturday, March 9.
The five good reasons to like spiders:
- Spiders consume 400-800 million tons of prey, mostly insects, each year. Humans consume somewhere around 400 million tons of meat and fish each year.
- Spider silk is one of the strongest naturally occurring materials. Spider silk is stronger than steel, stronger and more stretchy than Kevlar; a pencil thick strand of spider silk could be used to stop a Boeing 747 in flight.
- Some spiders are incredibly fast – able to run up to 70 body lengths per second (10X faster than Usain Bolt).
- Athough nearly all 47,000-plus spider species have venom used to kill their insect prey, very few actually have venom that is harmful to humans.
- Some spiders are really good parents –wolf spider moms carry their young on their backs until they are ready to strike out on their own; female trapdoor spiders keep their broods safe inside their burrows often longer than one year, and some female jumping spiders even nurse their spiderlings with a protein rich substance comparable to milk.
The itsy bitsy spider climbed up the water spout.
Down came the rain and washed the spider out.
Out came the sun and dried up all the rain
and the itsy bitsy spider climbed up the spout again.
It was an itsy bitsy spider.
But it wasn't climbing up a water spout.
It was lurking, waiting for prey, on our Mexican sunflower.
This particular crab spider was quite visible--white on orange. Sometimes they're so camouflaged that you have to look twice to see them. We remember the perfectly camouflaged crab spider on a gold coin flower (Asteriscus maritimus). (See below).
Crab spiders belong to the family Thomisidae, which includes about 175 genera and more than 2100 species. Wikipedia tells us that "The common name crab spider is often applied to species in this family, but is also applied loosely to many other species of spiders. Among the Thomisidae, 'crab spider' refers most often to the familiar species of 'flower crab spiders,' though not all members of the family are limited to ambush hunting in flowers."