They're ambush predators.
Here you are, a bee, touching down on a flower and little do you know there's a patient and persistent crab spider lying in wait.
Sometimes they're camouflaged, matching the color of a blossom, like a yellow crab spider on a gold coin, or a pinkish-white crab spider on sedum.
But there was no missing this white crab spider on a Mexican sunflower (Tithonia) last weekend. It stood out like a snowy owl perched on a crate of crimson pomegranates.
Crab spiders belong to the family Thomisidae and are often called "flower crab spiders." They're not web weavers or jumping spiders. They're ambush specialists that trap unsuspecting prey.
If you're wondering why some honey bees, leafcutter bees, blue orchard bees or sweat bees don't go home at night, the crab spider is one of the reasons.
It was a bad day for a butterfly.
We stopped by the Ruth Risdon Storer Garden, part of the UC Davis Arboretum, at noon today as triple-digit temperatures climbed to a scorching 103.
We spotted a few cabbage white butterflies (Pieris rapae) nectaring the Verbena (Verbena bonariensis), and a few honey bees on the gaura (Onagraceae).
The cabbage whites seemed to like the Verbena. They fluttered around the blossoms gracefully, touching down like snowy princesses in winged gowns and spiked heels, belying the fact that their caterpillars are pests of cabbage, kale, radish and broccoli, mustard and other members of the family Brassicaceae.
One cabbage white, however, wasn't so lucky.
As we rounded a corner of the garden, we noticed it wasn't fluttering. It wasn't moving. It wasn't doing anything.
There was a good reason why it wasn't going anywhere.
A hungry crab spider.
All that glitters is not gold.
The gold coin flowers (Asteriscus maritimus) planted in our yard attract a goodly number of leafcutter bees and hover flies (aka flower flies and syrphid flies).
But if you look closely, gold coins attract something else--arachnids.
This little crab spider (below) blends in so well that at first glance, it's not easy to spot.
And that's the key. Perfectly camouflaged, it awaits prey.
A golden opportunity...
It was not a good day for a flower fly.
A flower fly, aka syrphid fly, dropped down in a patch of pink roses at the Häagen-Dazs Honey Bee Haven at UC Davis today to sip nectar.
It was a pink-rose kind of day.
Not for the flower fly, though. A crab spider, lying in wait, pounced.
The battle ended quickly, but the syrphid-fly feast was not to be. Not today. The predator dropped its prey.
You can see lots of predator-prey action at the Häagen-Dazs Honey Bee Haven, a half-acre bee friendly garden located next to the Harry H. Laidlaw Jr. Honey Bee Research Facility on Bee Biology Road, west of the central campus.
It's open from dawn to dusk. Admission is free for all--including predators and their prey.
We can learn a lot from insects, especially when a predator ambushes its prey.
An ambush, as defined by Wikipedia "is a long-established military tactic in which the aggressors (the ambushing force) use concealment to attack a passing enemy."
The crab spider is a perfect example of an insect that conceals itself in a flower and waits for an unsuspecting visitor.
The crab spider doesn't build a web to trap its prey. No, too much wasted energy. It capitalizes on concealment, the element of surprise, and the quick assault and rapid kill.
And then, a leisurely meal.
Crab spiders or Thomisidae family (order Araneae) resemble crabs in that they can move sideways or backward.
You rarely notice them.
Neither do their prey--until it's too late.