Squatters' Rights

Aug 24, 2009

Squatters' rights.

A dandelion poking through the rocks near Nick's Cove on Tomales Bay, in Marshall, Sonoma County, seemed an unlikely host for squatters' rights.

It first drew a tiny bee, barely a quarter-inch long. It was a female sweat bee, family Halictidae, genus Lasioglossum, subgenus Dialictus.

She claimed the dandelion all to herself.

Not for long.

Another insect shadowed the dandelion and swooped down to feed.

It was a hover fly, family Syrphidae. (Probably a Eristalinus aeneus, observed UC Davis pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis.)

So on one dandelion: a fly and a bee.

The fly is bigger. But the bee can sting. The sting, however, is rated only 1.0 on the Schmidt Sting Pain Index compiled by (now retired) entomologist Justin O. Schmidt at the Carl Hayden Bee Research Center, Tucson, Ariz.

Fight or flight?


The dandelion blossom belongs to the fly.

By Kathy Keatley Garvey
Author - Communications specialist

Attached Images:

HOVER FLY, from the family Syrphidae swoops down on a dandelion claimed by a sweat bee. (Photo by Kathy Keatley Garvey)


TWO'S COMPANY--A tiny sweat bee and a hover fly share the same dandelion. (Photo by Kathy Keatley Garvey)

Two's Company

POLLEN-PACKING sweat bee (top) prepares to leave the dandelion to the much larger hover fly. (Photo by Kathy Keatley Garvey)

On the Rim

ALONE, the hover fly nectars the dandelion flower. (Photo by Kathy Keatley Garvey)