"World’s Smallest Bee" - Perdita minima

Perdita minima.
One of the smallest bees in the world, Perdita minima is rarely seen by the casual observer. Photo by John S. Ascher, Discover Life.

whitemargin sandmat.
Whitemargin sandmat (Chamaescye albomarginata) is one the many wildflowers in the Spurge family (Euphorbiacea) that Perdita minima visits. Photo by Margaret Williams, courtesy Nevada Native Plant Society.

By Steve Buchman
The Bee Works

Native bees come in all shapes and sizes. Many gardeners are familiar with the large black and yellow bumblebees (Bombus spp.) or the equally large, usually all black, carpenter bees (Xylocopa spp.). Honeybees (Apis mellifera) are much smaller, but they are giants compared to many of our nearly 4,000 species of native bees.

One southwestern United States bee is especially petite. Perdita minima belong to a diverse genus of approximately 600 species belonging to the family Andrenidae. Perdita minima are solitary bees, and thus are not classified as social bees as are honeybees. Many bees in this genus are floral specialists and only visit one or a few related species within a single plant genus.

Perdita minima are slightly less than two millimeters long! As a solitary bee, it constructs a diminutive nest in sandy desert soils. Entomologists and naturalists who seek out this tiny pollinator typically look for its passing shadow across the ground rather than the bee itself. This bee is so small that it can easily pass through and escape from the netting fabric mesh of ordinary insect nets.

male carpenter bee on a penstemon flower.
The smallest and the largest: a Perdita minima on a female carpenter bee's head. Photo by Stephen Buchmann.

Perdita minima feed on the nectar and pollen of wildflowers in the spurge family, Euphorbiaceae. In the desert southwest, it frequently visits wildflowers such as small whitemargin sandmat (Chamaesyce albomarginata). The tiny white flowers provide the nectar and pollen needed by adults and larvae of these small bees. Although pollen grains seem relatively large for such small bees to pack and carry back to their nests, the hairy legs of this diminutive bee are capable of being packed very large loads of pollen.