No Bee Is an Island: Hawaii Key to Saving America’s Bees
There are nearly 4,000 bee species native to the United States, ranging from the tiny, two-millimeter-long Perdita minima in the Southwest to the rotund black carpenter bees buzzing under the eaves of houses across the country.
The insects help pollinate more than $15 billion worth of crops annually, produce $150 million worth of honey, and assist in the fertilization of thousands of plant species.
Federal agencies such as the U.S. Fish and Wildlife Service and the Department of Agriculture tout the importance of bees, yet in the 43-year history of the Endangered Species Act, not a single species had been granted protection, despite a huge decline in wild bee populations.
This week, that changed. The Fish and Wildlife Service declared that seven species of Hawaiian yellow-faced bees—so named for the yellow markings on their faces—are endangered.
Yellow-faced bees—from the genus Hylaeus—are the only bees to have naturally colonized Hawaii. Scientists believe that the 63 known species on the islands are the descendants of a single ancestor. The Hawaiian bees comprise more than 10 percent of the world’s total yellow-faced bee species—more than are found in all of North America. They have adapted to virtually every habitat on the islands, ranging from the coastal beaches to elevations over 10,000 feet, pollinating native wildflowers, shrubs, and trees.
For bee advocacy group the Xerces Society, the listing of Hawaii’s bees is a key first step toward protecting other bee species, such as the rusty patched bumblebee.
That bee—named for the small, red-brown crescent on its back—was once common from Minnesota to Maine and south through the Appalachians, but Bombus affinis persists in only 10 percent of its historical range, relegated to a few strongholds in the upper Midwest. Federal officials are expected to determine whether the rusty patched bumblebee deserves endangered status by next year.
“The listing of the yellow-faced bees is a huge step,” said Sarina Jepsen, head of the Xerces Society’s endangered species program. “But the protections these bees get from the listing need to come alongside identifying and designating critical habitat they need to survive. We hope that’s the next step here and that the Fish and Wildlife Service makes those determinations for other bees facing extinction.”
The reasons for listing Hawaii’s bees are numerous, as all 63 species of yellow-faced bees on the islands are disappearing rapidly. In the early 1900s, bees were considered Hawaii’s most abundant insect, but a combination of habitat degradation, invasive species, sea level rise, and agricultural pesticides are suspected culprits.
Bee advocates said University of Hawaii senior researcher Karl Magnacca’s two decades of work have proved crucial to understanding their rapid decline.
“Karl in his previous work had assessed where certain yellow-faced bee populations were,” said Cynthia King, head entomologist at the State of Hawaii Division of Forestry and Wildlife. Magnacca had identified about 20 yellow-faced species he suspected were in danger. In 2014, King and fellow researchers visited a few locations on Oahu where Magnacca had found some of the rarest yellow-faced bee species, including Hylaeus anthracinus.
“We’d go to do assessments and get to the locations where the bees were located just five years ago, and we couldn’t find any,” said King. “That was startling. The bees were declining much quicker than we had anticipated.”
Today, H. anthracinus—one of the most studied species—is only found in two locations on Oahu, and a few small populations have been observed on other islands.
Jason Graham, an entomologist at the University of Hawaii at Manoa, came to the islands in 2014 to study the yellow-faced bees. He researched populations along Oahu’s North Shore, near Turtle Bay, and at the island’s south end, along the Ka Iwi Coast near Honolulu.
He discovered the solitary bees liked to nest in the hollows of certain native coastal plant species or in the holes of coral rocks that had washed ashore.
“That makes them very susceptible to tsunamis, big wave events, and sea level rise,” Graham said. “Last year, we saw that with the Turtle Bay population, where a big wave event wiped out a lot of the bees there.”
The bees compete with nonnative bees introduced to the island by humans. Graham discovered one invasive member of the Hyalaeus bee species originally from India that nests in the same corals and plants as the Hawaiian bees and forages nectar from the same flowers.
“Our bees are really lazy,” King said. “Most bees elsewhere are up at the crack of dawn, but we won’t even start looking for them until after 9 a.m. because they sleep in—they’re not used to the competition for nectar resources that they now have.”
Hawaii’s bees are harmed by ants, an insect that didn’t exist on the islands before colonization. Researchers have found ants will invade yellow-faced bee nests and feast on the unborn larvae.
Over the past year, Graham has been installing artificial bee nests for H. anthracinus—wood blocks with holes drilled in them—that allow bees in but keep ants out.
“We put this nontoxic substance called Tanglefoot along the bottom post to keep ants from crawling up, and it allows the bees to nest and leave the larvae behind,” he said.
In 2010, Graham built artificial nests for a locally rare species of chimney bees in Florida. He filled Tupperware with clay, the bees’ preferred nesting material. When the female bees left the larvae behind, he would move the Tupperware to a new location, and when the adult bees emerged from the nest for the first time, they immediately adapted to the new environment.
He thinks the same concept could work in Hawaii to reintroduce H. anthracinus to areas where it was once abundant.
“Creating diverse populations of these bees in multiple regions is key, and that’s the first step,” Graham said. “The next is determining what is critical habitat for these bees.”
When the Fish and Wildlife Service determines a species is endangered, it often identifies essential habitat that a species needs to survive. Such habitat can include geographic structures (such as corals for the bees to nest in) and plant species types (for the bees to forage).
In its determination that the Hawaiian bees deserved protection, the Fish and Wildlife Service stated it needed more time to identify the insects’ critical habitat.
That determination can’t come soon enough, according to Jepsen at the Xerces Society.
“Critical habitat needs to be designated at the same time of the listing of a species so that conservation actions can begin immediately,” she said.
On the mainland, the Xerces Society has petitioned federal officials to list the rusty patched bumble bee as endangered. The Fish and Wildlife Service proposed in September to add the bee to the endangered species list.
Jepsen was heartened by the proposal, but she fears that the government could delay designating critical habitat for a species already reeling from the impacts of intensive farming and potent pesticides.
She says the species needs its shrinking habitat to be designated and protected so that when development or a new agricultural pesticide is proposed, the impact on the rusty patched bumblebee’s survival must be considered.
“Everywhere these bees are in decline there have been large losses in natural habitat to farmland and increased use in pesticides including neonicotinoids—a known toxin to both commercial and wild bees,” Jepsen said. “If we can get the bees listed under the Endangered Species Act and get them to designate critical habitat, we hope there will be a way to make sure that some areas will remain natural landscapes, free of neonic use.”