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:

1. 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.
2. 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.
3. Some spiders are incredibly fast – able to run up to 70 body lengths per second (10X faster than Usain Bolt).
4. 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.
5. 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.

Strange thing, nobody ever says "as green as a green bottle fly."

'Cept maybe an entomologist.

You've heard:

• As green as an emerald
• As green as a lizard
• As green as a gourd
• As green as grass
• As green as bottled glass
• As green as it gets

But as "green as a bottle fly" (or blow fly in the family Calliphoridae)?

No. Most people cringe at the very sound.  They associate green bottle flies with their larvae, aka maggots, which eat rotting flesh. These insects lay their eggs in cadaver tissue. At crime scenes, forensic entomologists can determine the time of death by examining the developmental stage of the larvae.

And, of course, maggots are used  medically in maggot therapy (to consume dead tissue around live tissue).

Then there's Maggot Art, coined by a former UC Davis entomology major, Rebecca O'Flaherty. At the annual UC Davis  Picnic Day, children visiting Briggs Hall (home of the UC Davis Department of Entomology and Nematology) engage in Maggot Art, picking up a maggot with forceps, dipping it into non-toxic, water-based paint, and then letting it crawl on a white sheet of paper! Voila! Maggot Art, suitable for framing! (See Bug Squad, "Me and My Maggot."  Some of the young artists get quite attached to the maggots and ask their parents if they can take them home. Of course, the answer is "Yes!"  (Not!) Want to try Maggot Art? Mark your calendar for April 22, 2017 when the 103rd annual UC Davis Picnic Day takes place.

Green bottle flies can also be beautiful. Have you ever seen an emerald green bottle fly sipping nectar from a red flower, such as Lantana? When the light is just right, this little insect can make you say "Wow!"

Plus, it's a pollinator. It gets a little recognition, but not much, during National Pollinator Week.

Green bottle fly. (Photo by Kathy Keatley Garvey)

It's appropriate during National Pollinator Week to remember that.

We spotted this newly emerged green bottle fly (below) nectaring on lavender last week in our yard.

It seemed out of place among the honey bees, leafcutter bees and carpenter bees working the blossoms.

We didn't recognize it as a newly emerged green bottle fly, Lucilla sericata. But fly experts Martin Hauser of the California Department of Food and Agriculture and Terry Whitworth of Washington State University, did.

Family Calliphoridae.  Genus Lucilla. Species sericata.

"This looks like a Calliphoridae which just emerged, so the wings are still folded," said senior insect biosystematist Hauser.

Said Whitworth, an adjunct professor of entomology at WSU who maintains the websites birdblowfly.com and blowflies.net: "This is a teneral fly, not fully sclerotized. You can see it just emerged and the wings have still not extended so identification can be tough. However, the shot clearly shows three postacrostichals which almost certainly makes it the common, cosmopolitan Lucilia sericata."

Forensic entomologist Robert Kimsey of UC Davis marveled at the newly emerged fly. "Something dead in your yard?" he quipped.

"No," we said. "But the cat caught a rat the other day. We disposed of it quite quickly." Not the cat, the rat.

'Course, flies aren't known for being pollinators. They're better known--and rightfully so--for disposing of carrion and as the key tool in forensic entomology. They're also used in medical science as maggot therapy. And for art: one of Kimsey's former graduate students, forensic entomologist Rebecca O'Flaharty, coined the term "Maggot Art" (trademarked) and that's one of the activities at the annual UC Davis Picnic Day. Graduate and undergraduate students in the Department of Entomology and Nematology show youths how to dip a maggot in water-based, non-toxic paint, place it on white paper, and let it crawl. Voila! Maggot Art! Suitable for framing...

Everything in life--and death--has a purpose. 

"Go ahead, make my day."

So said actor Clint Eastwood, as the character Harry Callahan, in the 1983 movie, Sudden Impact, after a robber grabbed a hostage.

"Dirty Harry" was known for blowing away the bad guys. Clashes and confrontations often ended with blow flies on bad guys.

Recently a green bottle fly that touched down on our daylily "made my day." The rich golden blossom and the red-eyed insect with its emerald-green metallic body seemed to go together nicely.

I know. I know. A green bottle fly (Phaenicia sericata) isn't exactly the poster child of the insect world, but it is pretty.

Pretty on a golden daylily after an autumn rain.