Hawaii's yellow-faced bee species in the genus Hylaeus -- the primary pollinators for many of the islands plant life -- has been placed on the United States' endangered species list, the first for a bee species.

Last Sept. 30, the U.S. Fish and Wildlife Service declared seven Hawaiian Hylaeus species endangered, a sad event for a species that was among the most abundant of Hawaiian insects in 1900. This species of bees is essential to Hawaii's produce.

The six millimeter-long bees, which are often mistaken for wasps, are the only bees from Hawaii.

The U.S. Fish and Wildlife Service said it determined endangered status under the Endangered Species Act of 1973 for seven yellow-faced bees: Hylaeus anthracinus, H. assimulans, H. facilis, H. hilaris, H. kuakea, H. longiceps and H. mana.

The species gets its common name, yellow-faced, from a golden mark between the males' eyes. The bees sport black, shiny bodies without that classic bee fuzz or "scopa."

Federal protection of the bees will allow authorities to implement recovery programs, access funding and limit the harm done to them from outside sources.

Sarina Jepson, endangered species program director at the Xerces Society, said the bees are threatened by "feral pigs, invasive ants, loss of native habitat due to invasive plants, fire, as well as development, especially in some for the coastal areas."

Other scientists are blaming the bees' surprising loss in numbers to habitat loss, invasive species and climate change. They said only two known populations of H. anthracinus, one of the most studied species, remain on the island of Oahu. A few small populations are scattered across several other islands.

"What we saw was really alarming--the bees were doing a lot worse than we thought," said Cynthia King, an entomologist with Hawaii's Division of Forestry and Wildlife.

"We should protect the rarest of the rare."

Xerces Society is a non-profit environmental organization that focuses on the conservation of invertebrates considered essential to biological diversity and ecosystem health.