​New York, Dec 24 (IANS) Studying a diverse group of solitary, desert bees, researchers have reported identification of nine new species of the genus Perdita, including two ant-like males.

These solitary bees are not major pollinators of agricultural crops, but fill an important role in natural ecosystems of the American Southwest, including the sizzling sand dunes of California's Death Valley.

In a study published in the journal Zootaxa, the researchers described curious ant-like males of two of the species, which are completely different in appearance from their mates.

"It's unclear why these males have this unique form, but it could indicate they spend a lot of time in the nest," said entomologist Zach Portman from Utah State University in the US.

"We may find more information as we learn more about their nesting biology," Portman noted.

Portman tracked the tiny elusive bees by watching for their buzzing shadows in the blinding, midday sunlight the diminutive insects tend to favour.

"Their activity during the hottest part of the day may be a way of avoiding predators," Portman said.

"They appear to be important pollinators of desert plants commonly known as 'Crinklemats'" Portman explained.

Crinklemats, flowering plants of the genus Tiquilia, grow low to the ground and feature ridged, hairy leaves and small, trumpet-shaped blue blossoms.

"Like the bees, Tiquilia flowers are very small," Portman said. 

"The bees must squeeze into the long, narrow corollas and dunk their heads into the flowers to extract the pollen," he added.

The scientists reported that the female bees use pollen collected from the flowers to build up a supply to nourish their young. 

Once they have completed a pollen provision, the bees lay their eggs on the stash and leave their offspring to fend for themselves.

Though declines in bee populations have heightened awareness of the importance of pollinating insects to the world's food supply, numerous bee species remain undescribed or poorly understood, the researchers pointed out.