If you see a caterpillar near a cluster of aphids, don't squash it. It could very well be the larva of a syrphid or hover fly (family Syrphidae) and it's eating aphids.

What do they look like? I happened to capture an image of a  tiny syrphid larva on a rose leaf, and sure enough, it was eating aphids.  

Community ecologist Louie Yang,  who joined the UC Davis Department of Entomology faculty last year, has also photographed syrphid larvae. He recognized this one right away.

If you want to learn more about syrphid flies, be sure to read Flower Flies (Syrphidae) and Other Biological Control Agents for Aphids in Vegetable Crops, Publication 8285 (May 2008), UC Division of Agriculture and Natural Resources. It's primarily the work of UC Davis entomologist Robert Bugg; with expertise offered by Ramy Colfer, chief organic agricultural researcher, Earthbound Farms, Salinas; William Chaney, farm advisor, UC Cooperative Extension (UCCE) Monterey County; Hugh Smith, farm advisior, UCCE Santa Barbara and San Luis Obispo counties; and James Cannon, UC Davis computer resource specialist.

In the publicaiton overivew, Bugg writes that "Flower fly development involves complete metamorphosis, including egg, three larval stages, puparium, and adult. Adults of many flower fly species resemble stinging bees and wasps. This phenomenon is called Batesian mimicry, indicating that palatable organisms resemble or 'mimic' unpalatable models. Worldwide, there are many aphidophagous syrphid speices."

"Adult hover flies require honeydew or nectar and pollen to ensure reproduction, whereas larvae usually require aphid feeding to complete thir development."

Below, you'll see a syrphid larva doing what it does best: eating aphids. 

Last Saturday the rock purslane in our bee friendly garden drew a honey bee, several hover flies and one spotted cucumber beetle.

A hover fly landed on a blossom, only to find a spotted cucumber beetle there first.

Ah, rain!

Ah, liquid precipitation!

Just when we were feeling drought-stressed, the weather forecast turned to rain.

I don't know if "the rain in Spain falls mainly on the plain," but the rain in Northern California fell squarely on our bee friendly garden last weekend.

The honey bees weren't there, but the hover flies, aka syrphids and flower flies (family Syrphidae), were.

Winter is an etching, spring a watercolor, summer an oil painting and autumn a mosaic of them all. --Stanley Horowitz
 

Hover flies do know how to hover.

Like a helicopter with spinning blades, the hover fly lingers seemingly motionless in mid-air over a flower before zeroing down to feed on the nectar.

Sometimes they’re called flower flies. Sometimes syprhids. They’re from the family Syrphidae and mimic the black-and-yellow coloring of wasps or bees. The coloring protects them from predators. Leave me alone! Let me bee!

Last Sunday our rock purslane (Calandrinia grandiflora)  attracted its share of honey bees and hover flies.

In fact, so popular was the rock purslane (which we purchased from Ray and Maria Lopez of El Rancho Nursery and Landscaping, Vacaville), that I immediately wanted to fill the yard with the flower.

Instead I focused my macro lens, shot away, and then, for fun, altered the image in Photoshop with “poster edges.”

For a brief period, the hover fly became my poster child.